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Stupid Energy-Saving Tips

Martin’s roundup of ill-conceived internet tips

Posted on Dec 27 2013 by Martin Holladay

Just for fun, I recently Googled the phrase “energy-saving tips.” I dove deep — all the way to page 7 of the Google results. My research was profoundly discouraging.

Back in 2011, I wrote two articles about bad energy-savings tips. (See More Energy Myths and A Plague of Bad Energy-Saving Tips.)

Since then, is there any possibility that the quality of online advice improved? Not a chance.

Evidently, there is a secret stupid tips network (or stupid tips underground) that shares bad advice. Every now and then, some utility executive or government employee comes up with a new stupid tip, and (worried that the idea might not get the recognition it deserves) immediately sends out a mass e-mail to every member of the stupid tips network, so that the tip can be published widely.

Virtually every list of energy-saving tips on the Web includes some bad advice. The bad advice is so pervasive that I have decided to catalog these tips by category — to create a taxonomy of stupid tips.

The Top Ten List of stupid energy tips

Here’s my top ten list — common tips that show up repeatedly.

1. Fill your half-empty refrigerator or freezer with plastic bottles filled with water. This stupid tip will never save you enough energy to show up on your electric bill. Nevertheless, the advice is provided by the California Energy Commission, an electric utility called NV Energy, Avista Utilities, Wisconsin Public Service, Georgia Natural Gas, an electric utility called National Grid, Connecticut Light & Power, EnergyRight Solutions, and many others.

2. Clean the dust off your refrigerator’s heat-exchange coils. As I’ve noted before, researchers haven’t been able to measure any energy savings resulting from this measure. But a lack of data hasn’t stopped the following sources from advising homeowners to get out the vacuum cleaner: NV Energy, Connecticut Light & Power, and EnergyRight Solutions.

3. Schedule an annual furnace tune-up. As Michael Blasnik has shown, there is no evidence to support the idea that the cost of an annual furnace tune-up can ever be recouped by energy savings. This tip (often referred to as the “make-work-for-HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building.-techs” tip) is trumpeted by an electric utility called WE Energies, Wisconsin Public Service, a New Mexico electric utility called PNM, EnergyRight Solutions, and a utility named Alliant Energy.

4. Change your furnace filters monthly. Monthly? Really? Yes — according to Wisconsin Public Service and EnergyRight Solutions.

5. To reduce the rate of air leakage in your home, start by caulking around windows. Actually, the big leaks are in your attic and basement, not around your windows. That doesn’t stop many sources from offering the “caulk your windows” advice. Among the guilty are the California Energy Commission, NV Energy, WE Energies, the California Natural Resources Agency, Virginia Energy Sense, and a utility called NSTAR Electric & Gas. (The tip from NSTAR even includes a definition of the word “weatherize.” The site advises, “Weatherize your home by caulking and weather-stripping all doors and windows.”)

6. Install foam gaskets under your electrical outlet covers. There are only two problems with the advice: electrical outlets aren’t a major air leakage point, and gaskets don’t stop air leaks at this location. These two small problems don’t prevent the following sources from providing the tip: the California Energy Commission, a gas utility called PSNC Energy, Alliant Energy, and CNN.

7. Run your ceiling fans backwards during the winter. No researcher has ever been able to show that this practice saves energy. This tip may even make you uncomfortable enough to turn up the thermostat, raising your energy bills. But the advice is provided by Duke Energy, Alabama Power, an electric utility called Xcel Energy, and a Sustainability blog on the University of Illinois at Chicago web site.

8. Run your air conditioner and ceiling fans simultaneously. According to a 1996 paper (“Are Energy Savings Due to Ceiling Fans Just Hot Air?”) by P. James, Jeffrey Sonne, R. Vieira, Danny Parker, and M. Anello, “Data from 386 surveyed Central Florida households suggests that although fans are used an average of 13.4 hours per day, no statistically valid difference can be observed in thermostat settings between households using fans and those without them.” In other words, homeowners who run their ceiling fans and air conditioners simultaneously would be better off if they turned off their ceiling fans. This bad advice is provided by WE Energies and a utility called PSE&G.

9. Locate your air conditioner condenser in the shade to keep it cool. This myth was debunked many years ago by researchers at the Florida Solar Energy Center. Yet it still keeps cropping up, most recently in advice provided by PSNC Energy.

10. During the winter, close your curtains at night to save energy. When this advice is repeated, the authors usually fail to mention that you need a way to stop air from flowing between the curtain and the window — or else convection currents will sabotage your efforts to save energy. This incomplete tip is provided by many sources, including Connecticut Light & Power and the website of the National Association of Certified Home Inspectors.


REAL ENERGY-SAVING TIPS

After you've read the bad advice, you may be ready for some good advice. Here it is.

1. Seal air leaks in your attic and your basement. To learn more, see Air Sealing an Attic and Air-Sealing a Basement.

2. Add insulation to your attic if the insulation is thin.

3. Insulate your walls if they are uninsulated. (If you have a wood-framed house, you probably want to insulate your walls with dense-packed cellulose.)

4. Seal the seams of any ducts located outside the thermal envelope of your home, and add duct insulation if the ducts are poorly insulated.

5. Swap your incandescent bulbs for CFLs or LEDs.

6. If your refrigerator, furnace, or air conditioner is old, swap it for a new, high-efficiency appliance. Make sure your furnace blower isn’t on all the time. (It should be set to “auto,” not “on.”)

7. If your house has single-pane windows and you live in a cold climate, install low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor. exterior storm windows.

8. If you live in a cold climate and you heat with fuel oil, consider installing a ductless minisplit heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump. in your living room.

9. If you live somewhere with high electricity rates and decent PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. incentives, install a PV system.

10. Set back the thermostat when you’re not home or when you are asleep.

11. Unplug second refrigerators and freezers.


Tips which may save energy but which cost way too much to implement

A tip fails the cost-effectiveness test if implementing the tip costs more than will ever be saved by lower energy bills. Here are four tips in that category:

Install a backyard wind turbine. This energy-saving tip came from My San Antonio magazine.

Install a ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures.. This energy-saving tip came from U.S. News & World Report.

Install a solar water heating system. This energy-saving tip came from Duke Energy.

Install replacement windows. This energy-saving tip came from NV Energy.

Distractions intended to keep you busy rather than save energy

After the Allies defeated Germany and Japan in 1945, the U.S. government admitted that many of the war-time campaigns urging Americans to gather rags and steel cans for recycling were launched to give citizens a psychological boost rather than because of shortages of rags or steel. Many energy-saving tips have this same flavor: they are intended to keep homeowners busy — too busy to read the meter or pay attention to their actual energy bills.

The tips in this category usually focus on cooking. The basic problem with tips that save cooking energy is that cooking represents only 4% of U.S. residential energy use. So even if you can find a way to save 10% of the energy used for cooking, you will only save less than 1/2 of 1% of your residential energy use.

Clean the reflectors underneath your stovetop burners. Scrub all you want, but this effort won’t show up in your gas or electric usage. Still, this advice is provided by NV Energy and Duke Energy.

Always make sure that you have a lid on your pot when you’re cooking. This tip comes from an electric utility called Reliant, the city of Tallahassee, Florida, the city of Richland, Washington, and Alliant Energy.

Cook with copper-bottomed pans. This tip causes me to shake my head in wonder. It comes from Duke Energy.

Contradictory advice

If you read enough lists of energy-saving tips, pretty soon you will realize that some tips directly contradict other tips.

Close off heating registers in unused rooms — no, wait: leave them open. According to the city of Tallahassee, “Closing off rooms or registers will not save money and may lead to problems.” But Terry Webster from the Minnesota Office of Energy Security offers this energy-saving tip: “Close registers in unused rooms.”

Use a space heater — no, wait: never use space heaters. According to “Energy-Saving Tips” from TXU Energy, “Use Space Heaters. … There are days when you spend most of your time in one or two rooms. That’s when you should consider lowering your thermostat and using a space heater.” But another list — “101 Ways to Save Energy,” a document on an Alliant Energy web page — advises, “Avoid using space heaters, including electric, kerosene or propane models. Not only are they expensive to operate, they’re also very dangerous.”

Wild exaggerations

How good are utility executives at quantifying the energy savings that homeowners can expect by implementing their recommendations? They are really, really bad.

Window replacement. According to NV Energy, replacing “inefficient single-pane windows with energy efficient multi-pane, thermally-broken, vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate).-framed windows,” will “save you another 25% on your monthly bill.” According to Michael Blasnik, the saving in heating energy use that accrues from window replacement in cold climates is on the order of 1% to 4%. In a cooling-dominated climate like Nevada, electricity savings will vary greatly depending on many factors, including how shaded the windows are; but it is highly unlikely that electricity savings will approach 25%.

Choose the right sized pot when you are cooking. According to Wisconsin Public Service, “Just by using the right size pot on a burner, you can save about $36 a year if you have an electric range, or $18 a year with a gas stove.” Or perhaps 48 cents.

Caulk and weatherstripping your doors and windows. According to Virginia Energy Sense, this simple measure “can cut your energy bill by as much as 30%!” Or maybe 1%.

Annual furnace tune-ups. According to Alliant Energy, “A $50-100 annual tune-up can help reduce your heating costs by up to five percent.” Or maybe 0%.

Locating your air conditioner in the shade. According to PSNC Energy, this simple measure can increase the efficiency of your air conditioner by 10%. Or not.

Dangerous or counterproductive advice

This is a fun category: it consists of advice that can make things worse.

Open the vents on your crawl space during the summer. If you follow this advice, you will allow humid outdoor air to enter your crawl space. The humidity is likely to condense on cold surfaces, which can lead to mold or rot. It’s hard to imagine why this suggestion is on anyone’s list of “energy-saving tips,” but it is. It appears on lists posted by an electric utility called Dominion and Alabama Power.

Use a humidifier. This strange energy-saving tip can get you into trouble very fast, since the use of humidifiers is associated with sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. rot. Humidifiers are promoted as a good way to save energy by Georgia Natural Gas and Black Hills Power.

Add more attic ventilation. Unfortunately, homes that perform well without attic ventilation sometimes develop problems when vents are added. But some electric utilities are under the mistaken impression that adding attic ventilation can lower cooling bills, even though no researcher has ever been able to measure such savings. In spite of the lack of data, this measure is recommended by Reliant, PSNC Energy, and Long Island Power Authority.

Include an interior vapor barrier. In most climate zones, this is bad advice. Even in a very cold climate, this measure won't save you any energy. Nevertheless, you can find this tip on lists published by the state of Nebraska and Black Hills Power.

Install a fireplace. This may be one of the worst energy-saving tips ever devised. It comes from an article called “Remodeling Tips to Save Energy At Home” published by Living Green Magazine.

Tips that don’t belong

Sometimes, a list of energy-saving tips includes a few oddball items that were thrown onto the list by a desperate writer battling a press deadline. When you read the list, you wonder, “Now how is this supposed to save energy?”

“Recycle minor things; e.g., reuse empty soda bottles.” That energy-saving tip comes to you from a list on a site called Blackle.com.

“Install countertops made of bamboo.” That tip comes to you from an energy-saving tips list published by My San Antonio magazine.

“Placing a mat at the front and back doors of your home can cut the amount of pesticide residue tracked inside.” That’s one of the “Top Ten Energy-Saving Tips” provided by Goodhousekeeping.com.

Suggestions that are never going to happen

The next tip reminds me of the advice given in the 1950s by parish priests about marital relations: Marital relations happen sometimes, but the act probably shouldn’t involve any pleasure. According to United Power, a Colorado electric utility, it’s possible to save energy if you “set your hot tub heater thermostat to 102º F.” I’m sorry, United Power, but that’s not going to happen.

Another tip in this category is true but totally nuts. According to Duke Energy’s list of “100 Ways to Save Energy at Home,” you should “keep your thermostat close to the outside temperature.”

Yup. That will work.

Bizarre tips

If you read enough of these energy-saving tips lists, you end up with a few that can only be called bizarre.

Here, in its entirety, is an energy-saving tip from PSNC Energy: “Keep your appliances free of dirt and grease (which can reduce operating efficiency).”

So, after spending half a day wiping down my washer and dryer, how much energy will I save?

One useful website has advice for homeowners who want to do a thermal survey of their home, but who can’t afford an infrared thermometerA digital thermometer capable of measuring the temperature of a surface from a distance ranging from a few inches to a few feet. Most hand-held infrared thermometers include a laser to help aim the device; the laser plays no role in temperature measurement. Used as an inexpensive substitute for a thermal imaging camera, an infrared thermometer can detect hot or cold spots on walls, ceilings, and duct systems. or infrared camera. What’s the tip? Use your dogs and kids as sensors!

Here’s the advice from Avista Utilities: “Children and animals love comfort, and they can help us find possible heat loss in and around our homes. If there are areas around single pane windows, doors or vents that your kids avoid, consider checking for heat loss. Conversely, if you find the family dog or other living creatures living on the periphery of your home, it might indicate significant heat-loss coming from your floor into your crawlspace, which can translate to lost energy dollars.”

Finally, here is a tip from an article called “Easy Ways to Save Energy This Winter,” published by The Telegraph. It’s a real head-scratcher: “Curing fish with alcohol: When it’s really cold outside, sometimes cold alcohol-cured fish, accompanied by a strong drink like schnapps, can be a wonderful livener, as the Scandinavians know. Rub two whole fillets of salmon with a mixture of two tablespoons of sea salt, one tablespoon of soft brown sugar, a bunch of chopped fresh dill and a generous glass of vodka or schnapps. Sandwich together and put in the fridge, weighted down by a wooden chopping board and several kitchen weights or other heavy items. You can eat it after three days, and it will be good in a fridge for a week.”

Evidently the energy savings come from the fact that you don’t need to use the stove. Another side benefit: after you’ve had some schnapps, you can turn down the thermostat.

Martin Holladay’s previous blog: “Casey Makes a Bet.”

Click here to follow Martin Holladay on Twitter.


Tags: ,

52.
Jan 2, 2014 11:54 AM ET

Edited Jan 26, 2015 8:19 AM ET.

Response to Gordon Clements
by Martin Holladay

Gordon,
You are in the business of selling cellular window shades, so of course you are in favor of them. They're a good product. GBA has published glowing reports of this type of window quilt before; if you want to read what's been published here, start with these two links:

Insulating Window Shades

EcoSmart Double Honeycomb Cellular Shades

You wrote, "I wish GBA would say more emphatically that homes in cold climate with conventional single or double pane windows, which represent the majority in the US, would benefit from insulating cellular shades that provide a 4 sided seal if they are used appropriately."

It's hard to imagine how I could have written my advice in a way that would have been clearer. I wrote, "When this advice ('close your curtains at night') is repeated, the authors usually fail to mention that you need a way to stop air from flowing between the curtain and the window — or else convection currents will sabotage your efforts to save energy."

It seems that you agree with my advice, since you advocate the use of "shades that provide a four-sided seal" -- in other words, a type of shade that "stops air from flowing between the curtain and the window." I'm glad that we agree, and I'm glad that you sell shades that work.

In general, I think that GBA has presented a balanced view of your product. Cellular window shades are effective, but they aren't cheap. For cold-climate readers who can afford them, they can save energy and improve occupant comfort.

I think the jury is still out on whether this product is cost-effective.


53.
Jan 2, 2014 1:27 PM ET

Response to Martin Holladay (comment #44)
by john walls

This GSHP air handler unit has several zones (ducts going to various places that are individually thermostatically controlled). Each zone has it's own control damper. So, at any one time, the system may be conditioning a different quantity of zones. At some point, there may be only one zone being conditioned, and that zone may have relatively small needs---in fact, possibly so small that there would be insufficient flow across the coil for proper operation. To address this problem, one solution is to install an additional "zone" that "recycles" from the discharge plenum of the air handler unit back to the suction plenum. This "recycle zone" damper would open up only when needed to maintain adequate flow across the coil for proper operation, and to avoid high duct pressures, or any other issues associated with air-handler-unit low flow or restricted flow.
There are other control features to help the situation, like a multi-speed compressor and fan motor, but at some point, the recycle damper will have to engage.
So, the question is----in general, is there a significant efficiency impact (aka wasted energy) when in "recycle" mode? (i.e. one "regular zone" in operation with the "recycle zone" simultaneously in operation). Is the energy hickey simply the extra fan motor usage (higher air flow than needed for the one zone) or are there other factors at play?


54.
Jan 2, 2014 1:52 PM ET

Response to John Walls
by Martin Holladay

John,
My knowledge of zoned forced-air systems is imperfect, and is based mostly on this article by Gary Bailey: Zoning Forced-Air Heating Systems.

Bailey wrote:

"If a furnace was designed to deliver air to 12 duct runs, but only two dampers are open in one zone that’s calling for heat, the furnace would be at risk of damage from heat stress. The ideal way to cure this problem would be to use a multi-stage furnace, where the burner can fire at different rates, but that only makes sense if you’re replacing the furnace.

"When adding zoning to an existing system, the best way to get rid of excess heat is to create a separate “dump zone,” which throws extra heat into an unused part of the house — a basement workshop, for instance, or an upstairs storage room or insulated garage. If the furnace sits in an unfinished basement, there’s no harm in dumping the heat directly to the surrounding air.

"Another way to get rid of excess heat with a Carrier multi-stage furnace is to use a bypass loop between the supply and return trunks. If the airflow falls below a certain level, the difference in pressure opens a simple barometric damper and sends air back to the furnace.

"Many times, we have to combine bypass loops and dump zones to get an acceptable result. Neither of these methods is energy-efficient, but most clients are willing to waste a little heat to gain the comfort a zoned system provides."


55.
Jan 2, 2014 9:51 PM ET

Response to Robert Connor's comment 31
by Jonathan Teller-Elsberg

Robert, I don't think asking "why has no one taken my advice about thinking about and limiting family size?" is the right question. Silence in the comments does not mean that people think you necessarily wrong, only that there is no need to say anything in response. Your comments that people can reduce energy consumption through having fewer children is not controversial. No one is going to rebut your argument and claim, "I reduced my utility bills by having another child." Also, the focus of Martin's blog has been primarily on cost-effective energy savings. Whatever their impact on utility bills, kids are definitely money sinks.


56.
Jan 6, 2014 4:01 PM ET

Tips that save energy but cost too much: Not one-size-fits-all
by Seth Romme

Martin: I like the article, nice job. We've done energy myth buster seminars similar to some of these one-liners for quite some time now. The "Tips that save energy but cost way too much to implement" section is something I think is worth a little questioning. As an example, a ground-source heat pump can absolutely be the the smartest financial decision & save energy (here in Wisconsin). Whether or not that is the case is completely dependent on the heat loads, fuel source you're replacing, and the install cost. As energy advisors, we've financially justified numerous ground-source heat pumps given those 3 home-specific factors.

On top of that, whether or not it costs too much now and going forward is heavily reliant on what predicted energy inflation rate is being used as well as the interest rate of financing. The same principle applies to replacement windows. Sure, replacing windows solely to save energy dollars is an impossible money-saving scenario. However, many many people are replacing windows because they have to (mold, rot, etc) or simply want to (aesthetics). In that case, you definitely can get a return on the incremental cost of energy efficient windows depending on the the other variables of the home: structure, fuel source, loads, etc.

The need for custom analysis on a home-by-home basis is why we started doing independent home energy advising. Each home is unique, which has proven to yield different smart, energy efficient recommendations. We've seen the best financial options be ground-source, while others are typical gas-fired furnaces, or some triple pane windows, others double pane. It truly rarely is a one-size-fits-all situation, but every home has a perfect size with upfront modeling and optimization!!


57.
Jan 6, 2014 4:13 PM ET

Response to Seth Romme
by Martin Holladay

Seth,
It seems that you agree with me about window replacement, since you wrote, "replacing windows solely to save energy dollars is an impossible money-saving scenario." The fact that people do it for other reasons is irrelevant to the topic of my article.

When it comes to ground-source heat pumps, I simply disagree. Ground-source heat pumps are almost never a good investment for owners of single-family homes. For more information on the background of my views, you might want to read Are Affordable Ground-Source Heat Pumps On the Horizon?


58.
Jan 6, 2014 5:53 PM ET

Response to Martin Holladay
by Seth Romme

Martin,
I read your article on GSHPs including a handful of the comments and your responses to them. I enjoy the added perspectives from all around. As an independent energy advisor for both homeowners and builders, I am far from a die-hard GSHP advocate, but I'm weary of using generalities regarding its positive or negative financial impact without the exact home's specifics (fuel source availability, rates, loads, etc). That being said, I don't think the $20k range is that few and far between for an installed GSHP system, at least here in WI. Two different projects that I've consulted on recently have come back with $20k and $21k GSHP quotes from separate installers (before any credits/rebates). The $21k was for an in-floor system on a 1500 conditioned square foot home, while the $20k was for a forced-air system on a ~4,800 conditioned square foot home. In the case of the $20k, my alternative for a LP furnace+AC was about $15k. That $5k cost increase and about 3.1 CoP meant the homeowners would save about $29 the very first year (mortgage increase less energy bill savings) and about $4.5k over 20 years (4.25% interest, 5% energy inflation) with the GSHP.
As close to a generality as I can get at this point, given all the homes I've looked at in WI over the last couple years is that a GSHP cannot be financially justified when the home has access to natural gas, and thus can go with a NG furnace+AC. Reason being, with our current fuel rates the $/mmBTU is: $38 electricity and $7.90 NG. For round number's sake say $40 and $8. That means the GSHP would have to have a COP of 5 to even match the operating cost of the NG furnace throughout heating season...not happening (as you've alluded to). In this case, install cost makes no difference at this point because GSHP is not less than a forced air + AC. Even with this "close to generality," I continue to automatically model the financial viability of it on every NG project to ensure the builder or homeowner sees the facts, specific to their home.
Perhaps these GSHP install costs are a WI thing? Or our fuel rates (elec, LP, NG) are that different than other parts of the country? Very interesting!!


59.
Jan 7, 2014 9:11 AM ET

Response to Seth Romme
by Martin Holladay

Seth,
You are comparing the cost of a ground-source heat pump to a $15,000 forced air furnace. But for some reason, you aren't comparing the cost of a ground-source heat pump with one or more ductless minisplits, two of which can cost $5,500 or $6,000 installed.


60.
Jan 7, 2014 9:46 AM ET

Edited Jan 7, 2014 9:47 AM ET.

Response to Martin Holladay
by Seth Romme

Martin,
We've looked at minisplits and in WI, not only have we seen that they aren't as cost effective, but the market is also saying that. Even the lowest cost homes (the ones who are willing to save a couple hundred bucks by installing elec DHW rather than gas) aren't installing minisplits. The budget systems are always forced air furnace with ACs.
To get the right comfort level in our basements and all other levels and rooms of the home, the minisplits become too expensive. To try and improve comfort, we've looked at ducted minisplits but we then start getting into additional cost issues with the ducting in order to really move the air properly.
The fact is, every home needs its own unique analysis to identify which energy component is the best return. Whether it be the HVAC, the amount of attic insulation, or the performance specs of the windows.
In regards to GSHP and their true CoPs, you may find this home tracker interesting. To stay true to our independent roots and continue to learn from real data, we've been tracking this home that we provided energy advising on for several years now (room by room temps, GSHP incoming/outgoing temps, etc): http://welserver.com/WEL0316/
Thanks for the great discussion!


61.
Jan 7, 2014 11:25 AM ET

Interesting article
by David Profitt

Still not sure if you wrote this just to get responses or if you're serious. About 10% is valid, the rest is, well, varying degrees of not-so-much. As Seth Romme pointed out, every house is different, just like the people who live in them. What is hard fact in one instance is fantasy in another. The Florida based test that determined shading the AC compressor did not increase it's efficiency was, I'm sure, true - in Florida where the humidity is near 100% all summer long. Do that same study in a low humidity climate like Arizona and you'll get starkly different results. Same goes for the ground coupled heat pump. It may not make financial sense in a cold climate line MN, but what about taking that to a humid heating climate like Florida, as ambient humidity is a major factor in an AC compressor's ability to get rid of the heat it's collected inside the dwelling.

The window leakage part was particularly amusing, as old single pane windows (or poorly installed new ones) can be a major source of air infiltration. R-value doesn't matter much if you've got a 5 mph breeze blowing thru on a windy day. Insulation slows the transfer of heat - it provides neither heating or cooling effects. This is not to say it isn't important - it's just only part of the story.

As it's a cold day and I"m stuck inside, just for fun I'll address them briefly:
1. The water bottles in the freeze. Run that one by a physics professional. If he has a sense of humor (not common in that profession, I admit) , he (or she) will find it amusing.

2. The refrigerator coils. These coils sweat in the performance of their job. In a typical house, this will collect dust. The job of these coils is to be a radiator. Dust buildup becomes an insulator. The physics guy can explain this one also.

3. Schedule a furnace tune-up. Furnace burners get very hot, then cold. They sweat. They rust. Then they leak. This is bad. This can happen fairly quickly.

4. Change your filters monthly. Not valid, especially if you still have those leaky windows and other air leaks. A month may be tool long. Change them when they look dirty.

5. Caulking around your windows. If you have a draft coming around your windows, caulk them. Storm windows won't fix this. When you can afford it, get new windows. Complete units, not the "pocket" replacements all the window companies want to sell you. They won't stop air leaks around the window jambs. Especially if you live in an older home. And have had the walls insulated. The space around the window jambs didn't get any.

6. Foam gaskets under outlet covers. If you can feel air coming out of these locations, the gaskets won't fix the problem but will definitely help. You may need longer screws to re-attach the covers. Better still get over size cover plates (and the gaskets) as the the area under the cover plate is frequently cracked or crumbling.

7. Run your ceiling fans backwards. Only if you want the heat down where your body is (that pesky physics thing again).

8. Run ;your AC and ceiling fans simultaneously. This one is iffy on energy savings, but it's big on comfort level. It keeps the air moving, encouraging uniform temperatures. At my house, if my wife feels cold in her sewing room, the thermostat goes up even if I"m warm & cozy in my sun-filled office. Keeping the fans going helps keep the thermostat setting down (or up, depending on the season). There is a cost to running these fans, both in short term electrical costs and long-term wear and tear, but my experience thru the years has proven it to be a wise move.

9. Locate your AC unit in the shade. You probably don't have a choice in this, as the location was determined by many factors that didn't have anything to do with energy efficiency. If you are in an area of high humidity, it won't matter (like Fl). If you are in a low humidity area, shading the unit has been proven to help. Don't take my word for it, do a little poking around on the DOE website.

10. Closing the curtains in the winter. Depends on your windows, the way the window is facing and the weather. On a bright sunny day the solar gain thru a (caulked) 50 yr old window may still be advantageous.

Tips that cost too much. The GSHP and windows will typically increase the re-sale value and the saleability (two different factors) of your home. A well designed SWHS can also help with space heating. Saving energy and increasing comfort are also a plus. Don't understand why that $30k UV array was missing from this list.

Real energy tips:
1. I'm good with that one.
2. Good, but how much is too thin?
3. Good again, but skip the cellulose if you live in one of those high-humidity areas (like FL). Paper, I mean cellulose, is a porous materiel, no matter what it's treated with.
4. Good. Better yet, have a professional do it.
5. Good, maybe. Don't count on energy savings with the LED's just yet, especially in recessed fixtures. They can actually produce more heat at the socket than the incandescent they are replacing.
6. Good idea on the fridge, not so much on the furnace blower.
7. Depends on the house, the climate.
8. A good one-room comfort solution but not in a cold climate. Air coupled heat pumps are better than they used to be but when the temps drop into the 20's they kick in resistance heaters and the meter starts spinning. Good in warmer climates though.
9. Depends on the climate, exposure, cost, rebates and whether the electric companies follow the trend of Hawaii and stop requiring the power companies to buy back the power. Other states are considering this as the resulting power regulation of the grid is a nightmare.
10. Depends on whether you will be home during the day or not. It's that physics thing again....
11. Ok this time of year, put your beer outside.

Contradicting advice:
Close off registers in unheated room. Remember that thing about what insulation does? When you close off these rooms they gradually become outside temp, Now you have an UN-insulated wall between you and whatever the outside temperature is.

Wild Exaggerations
Window replacement. Varies with individual application.

Caulk and weatherstrip. If you have on the best cold weather coat that money can by and you turn your uncovered face into a 10 mph wind does your nose get cold? Anything you can do to stop air infiltration (U value in modern building lingo) will increase comfort and decrease heating and AC costs.

Open crawl space vents in the summertime. Guess what? If you live in a humid area like the south, there will be humidity under your house, vents open or closed, all year round. In the Southern states, many code models prohibits all the vents from being closeable. The best solution is a properly and permanently sealed crawlspace (also permitted under those codes). Or leave the vents open. Air movement (even humid air) will help prevent excessive moisture accumulation.

More attic vents. Improperly placed and sized attic vents do more harm than good. Soffit venting and corresponding ridge venting will promote airflow (physics again), though the reversal of this airflow at night as temperatures cool will allow the moisture laden air to condense on the attic insulation, reducing it's effectiveness. Better alternative: seal the attic space from the outside air with a combination radiant and moisture barrier. Works great! Keeps the insulation dry and keeps the attic space significantly cooler in the summer, prevents heat loss thru convection in the winter.

Instal a fireplace: But they look nice.....

Thanks for the article. It provided some entertainment on a cold boring day stuck in the office. But come on, you weren't really serious, were you???

Engineer-turned-Builder (28 yrs ago). You didn't really think we were all carpenters or MBA's, did you?


62.
Jan 7, 2014 12:33 PM ET

Edited Jan 7, 2014 12:38 PM ET.

Response to David Profitt
by Martin Holladay

David,
You wrote, "1. The water bottles in the freeze. Run that one by a physics professional. If he has a sense of humor (not common in that profession, I admit) , he (or she) will find it amusing."

Q. I'm not sure I understand your point. How many kWh per year will the trick save? Without data, your point is lost. We're looking for tips to save homeowners money on their energy bills. If you replace a volume of air with cold water, you limit the amount of air that spills out of the refrigerator when you open the door. I get it. So what? It's not worth the trouble.

You wrote, "2. The refrigerator coils. These coils sweat in the performance of their job. In a typical house, this will collect dust. The job of these coils is to be a radiator. Dust buildup becomes an insulator. The physics guy can explain this one also."

Yup. Coils get dusty. So hook up your handy watt-hour meter and tell me how many kWh per month your trick saves.

You wrote, "3. Schedule a furnace tune-up. Furnace burners get very hot, then cold. They sweat. They rust. Then they leak. This is bad. This can happen fairly quickly."

So if you are worried about a rusting heat exchanger, by all means schedule a furnace tuneup. Just don't expect that you will recoup your $200 annual payment to the HVAC tech in energy savings, because you won't.

You wrote, "4. Change your filters monthly. Not valid, especially if you still have those leaky windows and other air leaks. A month may be too long. Change them when they look dirty."

You seem to agree with me: change them when they're dirty. So, in your house, is "a month too long"? Are you on the every-two-weeks schedule? Heavens, your house is dusty.

You wrote, "5. Caulking around your windows. If you have a draft coming around your windows, caulk them. Storm windows won't fix this. When you can afford it, get new windows."

You and I agree: if you know where to caulk, by all means caulk. But caulking windows is not a definition of "weatherizing." Weatherizing starts in the attic and basement; windows are way down the list. Any if you want to replace your windows, go ahead. You'll never save enough energy to pay for your new windows, however.

You wrote, "6. Foam gaskets under outlet covers. If you can feel air coming out of these locations, the gaskets won't fix the problem but will definitely help."

So we agree.

You wrote, "7. Run your ceiling fans backwards. Only if you want the heat down where your body is (that pesky physics thing again)."

There is absolutely no evidence that this improves comfort. And it certainly won't lower your energy bills. I believe in physics, like you, but I also believe in comparing pre-retrofit to post-retrofit energy bills. Running ceiling fans backwards during the winter will raise your electricity bills without lowering your space heating bills.

You wrote, "8. Run your AC and ceiling fans simultaneously. This one is iffy on energy savings."

Right. As in, there is absolutely no data to support it.

You wrote, "9. Locate your AC unit in the shade. You probably don't have a choice in this, as the location was determined by many factors that didn't have anything to do with energy efficiency. If you are in an area of high humidity, it won't matter (like Fl). If you are in a low humidity area, shading the unit has been proven to help."

Cite me the study. Website tips don't count.

You wrote, "10. Closing the curtains in the winter. Depends on your windows, the way the window is facing and the weather."

I'm not sure what your point is. Show me the study that documents energy savings.

You wrote, "The GSHP and windows will typically increase the re-sale value and the saleability (two different factors) of your home."

Show me the study.

You wrote, "Saving energy and increasing comfort are also a plus."

I wrote that these tips save energy; they just aren't cost-effective.

Q. "Real energy tips. ...Good, but how much is too thin?"

A. If you have good access to your attic, blow in enough cellulose on the attic floor to meet the minimum R-value requirements specified in the International Residential Code for your climate zone.

You wrote, "Good idea on the fridge, not so much on the furnace blower."

I disagree. Running a furnace blower, which can draw 600 watts, 24/7 can add significantly to your electric bill. Switch it to "auto."

You wrote, "Window replacement. Varies with individual application."

The fact is, it's never cost-effective.

You wrote, "Anything you can do to stop air infiltration (U value in modern building lingo) will increase comfort and decrease heating and AC costs."

I'm a big fan of blower-door-directed air sealing. The work is mostly done in the attic and basement. And by the way, U-value (more accurately known as "U-factor") has nothing to do with air infiltration. U-factor is the mathematical inverse of R-value.

You wrote, "The best solution is a properly and permanently sealed crawlspace (also permitted under those codes). Or leave the vents open. Air movement (even humid air) will help prevent excessive moisture accumulation."

You are correct on the first point, but wrong on the second. If the outdoor air is warm and humid, the more air movement, the wetter your crawl space becomes.


63.
Jan 9, 2014 10:53 AM ET

some comments not already raised...
by Muriel Strand

very interesting discussion.
i don't understand why a ceiling fan would use significantly more energy in one direction than the other?
i think putting lids on pots makes them heat faster, and it's wise to keep the flame (or coil) UNDER the pot not escaping up the sides.
i think my relatively new and wonderful bottom-freezer fridge has the coils covered in back. presumably the mfr. found that keeping the dust off ensured ongoing energy efficiency.

my uncle built a supplementary solar air heater that worked very well for him when the sun was shining. 12-oz cans painted black and fixed to the inside of a plenum with a transparent top, with the plenum slanted up toward the house and a vent at the top of the wall that he closed when it wasn't sunny.

i think ducts are the work of the devil.
fortunately my cottage came with a double-wall gas heater which i replaced with a gas fireplace-stove that's surrounded by some bricks for thermal mass and shielding in back for passers-by in the hall. the stove uses rather less gas than the old furnace, and the same thermostat which i mostly just turn on and off for comfort. and i have ceiling fans in every room tho generally just use the one near the stove. if i had a larger house i would just add more such stoves than install ducts. and of course i can close off a room and save some energy, depending on diurnal timing.

when i had the old gas furnace, i got a lot more condensate from the combustion water getting out into the room air, and i had some humidity problems. but no way could i find a humidifier that would work in cold weather which was what i needed - they were all designed for louisiana summers.

i also find that in my dotage i can forgo bathing longer than in my salad days, when i was green and oily. it's also not that hard to just wash the stinky bits to tide yourself over. and i hope that i'm not shortening the lifespan of my water heater thermostat by turning it up only when i actually want a nice hot shower. or bath.

and i had the foresight to buy a house with large southwest shade trees, so i can get by with a whole house fan. and a wet t-shirt on really hot days, since i live in a mediterranean climate. (i live alone, not an energy saving measure.)

at one point i looked into zoned heat pumps and air-air heat exchanger. they seemed like they would make life a little more complicated, and the latter also uses energy.

about cost-effectiveness: it's dangerous to just look at the money, because money can never be the independent variable. given our fossil fuel addiction, energy conservation is the real independent value. how valuable? it would take a healthy adult a good 100 hours of continuous effort to generate the amount of energy available in a gallon of gas. if memory serves, we're good for about 75 watt. so can we afford ourselves? here are some considerations: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2222988

soon i expect to install one or 2 light tubes, and i would be very interested in your assessment of those.

thanks, muriel strand, p.e.


64.
Jan 9, 2014 11:09 AM ET

Edited Jan 9, 2014 11:12 AM ET.

Response to Muriel Strand
by Martin Holladay

Muriel,
You wrote, "When I had the old gas furnace, I got a lot more condensate from the combustion water getting out into the room air, and I had some humidity problems."

If the moisture from the flues gases produced by your furnace were entering your living space, that means that you either had a cracked heat exchanger or a blocked flue. Both conditions are dangerous. Normally, all of the combustion gases (and their associated moisture) should leave your house through the flue.

You wrote, "No way could I find a humidifier that would work in cold weather which was what I needed."

It's a good thing that you couldn't find a humidifier, because humidifiers cause lots of problems. It's usually dangerous to operate a humidifier. Humidifiers can cause wall sheathing and roof sheathing to rot.

I'm not sure what you mean by "light tubes," but if you are talking about linear fluorescent lamps, they are a good choice. The best fluorescent lamps (T-5 or T-8 lamps) have an efficiency of 98 to 105 lumens per watt. For more information, see Martin’s 10 Rules of Lighting.


65.
Jan 9, 2014 11:24 AM ET

Hot climate resident that saves energy by using ceiling fans
by Linda Foss

Just because some people might not adjust their thermostats when they use ceiling fans does not mean that they are better off not using the fan. The better advice is for them to turn the thermostat up and turn on a fan. And of course to turn off fans in rooms not in use.

I keep my AC set around 80 and am comfortable with the use of a fan in the rooms in use. And of course, I dress right for the climate. That's another thing few people know how to do anymore. The loss of common sense over the last few decades is astounding. I know someone who is a green builder & director of a green building resource center. We toured his home where he has been doing a number of energy & water saving projects. The ceiling fan on his porch was going the whole time, with no one out there. And he was thrilled to share his astounding rediscovery of opening doors and windows on nice days. Saying we all forgot. I never forgot and can't imagine ever having forgotten. The days we can have the house open are the best days of the year.


66.
Jan 9, 2014 11:25 AM ET

postscript
by Muriel Strand

other energy conservation measures include wooden or other solid floor coverings. carpeting requires vacuuming, but throw rugs are easily shaken outdoors. also, manual lawnmowers and rakes offer great exercise. and of course, nobody needs an electric can opener. plus which, canning is not as energy efficient as food preservation by drying.

and there is also the tiny house movement...


67.
Jan 9, 2014 11:34 AM ET

light tubes
by Muriel Strand

light tubes are slightly specialized skylights: http://www.jmjnaturallighting.com/content/show/6931

as for the old gas furnace, i'm quite sure the flue was working. i don't know about the heat exchanger, but the heater seemed to be designed in such a way that the flame was somewhat visible, so i had to be getting some of the combustion exhaust water tho by no means all. it was a standard item, like the sears "Empire Comfort Gravity MV 25000 BTU Wall Furnace - Natural Gas" but dating probably from the 1970s at the latest.

but if a de-humidifier actually worked, there should be no mold hazard?


68.
Jan 9, 2014 11:54 AM ET

Response to Linda Foss
by Martin Holladay

Linda,
I agree with you about ceiling fans -- and so does Carl Seville, another writer here at GBA. For more information, see:

Using Ceiling Fans To Keep Cool Without AC

Ceiling Fans Are Evil


69.
Jan 9, 2014 11:59 AM ET

Response to Muriel Strand
by Martin Holladay

Muriel,
Tubular skylights are a mixed bag. They punch a big hole in your thermal envelope (your insulation layer), so they will raise your energy bills. Some people like the light they produce, however. If you work outside of the home, and you aren't home during daylight hours, you won't be able to take advantage of the light. However, if you work at home, they may slightly lower your electricity bill (while raising your heating and cooling bills).

In Comment #63, you said that you wanted a humidifier. In Comment #67, you said you wanted a dehumidifier. Big difference.


70.
Jan 9, 2014 12:37 PM ET

oops i meant de-humidifier
by Muriel Strand

does the de-humidifier exist that will work in the winter?


71.
Jan 9, 2014 12:52 PM ET

Respose to Muriel Strand
by Martin Holladay

Muriel,
Many people install dehumidifiers in their basements, which are often cool. So, yes, dehumidifiers should work just fine indoors, in rooms that range from 50 degrees F to 80 degrees F.

However, if you want to lower your indoor relative humidity during the winter, you don't want to use a dehumidifier (which is an energy hog). You want to use a ventilation fan.

If you don't have a ventilation system in your house, leaving your bathroom exhaust fan(s) operating for 24/7 will lower your indoor humidity levels pretty quickly -- and will use less energy than a dehumidifier.


72.
Jun 30, 2014 12:32 PM ET

Another tip
by w d

It's refreshing to read a sober and factual assessment of energy saving tips and the amounts that may be saved.

We've reduced our gas and electricity usage by 50% over the last 10 years or so. Numerous projects were involved. Of these, the greatest electricity savings came from installing solar grates. These savings occur when the Utility also benefits because peak demand is reduced. The Utility informs us we are now using 41% less electricity than the 20% most efficient homes of like size in our area. No windmills or PV are in use.

Solar screens and solar grates are similar in their savings effect. Solar screens darken the room some and are recommended for permanent installation to avoid damage in handling. A view is maintained even though the screen is 80% closed. The curb appearance is changed some.

Solar grates are three dimensional and operate to largely absorb infrared while mostly reflecting visible light. This selective reflectivity saves a/c electricity while illuminating the interior (think cool and bright). Maintenance is nil and the grates are designed for seasonal use. The curb appearance is changed. The grate is 80% open and the interior view head-on is good while curtailed at large angles. The view is maintained at night. In winter the grates are stored, allowing the sun to heat the home.

It simply makes no sense to allow the summer sun to heat the home (or other building) and then use the air conditioner to overcome the solar heat gain. Better to absorb the infrared before it passes the window into the building interior (becoming part of the a/c load) and to smile when you get your next utility bill.


73.
Aug 20, 2014 10:08 AM ET

More questionable tips
by Jonathan Beers

The "reverse your ceiling fan direction" tip lives on: http://theenergycollective.com/sbattaglia/452336/diy-friday-5-ways-cut-y...


74.
Aug 23, 2014 12:36 PM ET

Best energy saving tip ever!
by Mark Woodruff

Explode a 100+ megaton thermonuclear warhead in any old volcano. The resulting dust in the atmosphere will not only greatly reduce the global temperature, but the potential extinction of mankind could lead to the largest energy savings ever!

I asked Dr. Evil for most specific figures. He said he didn't have them yet, but was working on it...and would have results soon. Bwa ha ha ha....


75.
Feb 1, 2015 3:36 PM ET

Put a Shine on Lightbulbs - Add to the Keep You Busy List!
by Julie Tolliver

This Old House - 28 Small Steps to Big Savings - "Dirty bulbs emit 30 percent less light than clean ones, according to the U.S. Department of Energy (DOE). If the room is dimmer, you might get the urge to turn on more fixtures. Instead, dust bulbs in lamps and other open fixtures regularly with a clean, dry cloth; just be sure to switch off the lights and let the bulbs cool thoroughly first, as heated bulbs can shatter.

The Payoff: Every additional LED lightbulb you don't turn on for, say, 5 hours a day, saves about $3 a year. Don't switch on seven extra light sources for that amount of time and save about $21 a year."

By the way, as a Home Performance Contractor, I really appreciate this "Stupid Tips" article and all of it's comments. Clients ask me all the time "I heard that...will save me energy'' and this has been a great source to be already familiar with...such things and have ready-rebuttals! Not to mention, it's always amusing!

I turned my LED bulbs off when I started writing this - they should now be cool enough for me to spend the rest of the afternoon dusting! I'm gonna rake in the savings!!


76.
Sep 24, 2015 12:02 PM ET

More questionable energy tips
by Jonathan Beers

Gotta love this one: " 3. Redecorate with more carpeting. More carpet means more heat insulation – and also an opportunity for more homey decor. The rugs are made of heat-absorption material that collects the heat that is normally lost on hardwood floors."

From Arcadia Power's blog, “10 Easy Ways to Save Energy at Home,” posted On 22 Sep 2015.


77.
Sep 24, 2015 12:20 PM ET

Response to Jonathan Beers
by Martin Holladay

Jonathan,
Classic gibberish! "Heat-absorption material" has a nice ring to it.

How about Tip #7? "Move around some furniture." Now that's got to save oodles of energy. I'm going to try it today.


78.
Sep 24, 2015 12:57 PM ET

Love the cookies too! :-)
by Dana Dorsett

http://blog.arcadiapower.com/10-ways-make-home-energy-efficient/

"We know it is tempting to look at the deliciousness – but patience is much more than a virtue here. If you keep your oven door closed you can save a large amount of energy in such a simple way. The oven already takes a large amount of time to heat up, so imagine the amount of energy you release when opening up the oven even once – let alone the five times you already do when baked good are inside."

Don't "....imagine the amount of energy you release when opening up the oven even once..." - calculate it!

Assuming even a very large 8 cubic foot oven at 350F in a 70F room, and assuming that 100% of the air is replaced when you open up the door...

(350F-70F) x 0.018 BTU/degree-ft^3 x 8 = 40.3 BTU, or about 0.01kwh.

Almost all residential range ovens are between 4-5 cubic feet, and, the actual air exchange is probably only ~50-75%, not 100% so you're really looking at about 15 BTU, or 0.004 kwh.

If you check the cookies 5 times with a fully open door for a good gulp of air exchange that's about 0.02 kwh. Even in high priced electricity areas (which is usually WELL over the energy cost of gas-fired oven) where retail electricity costs 25 cents/kwh, that's about 1/2 of one cent.

If you turn the 40 watt oven light for the 10 minutes of baking time (as shown in the picture on that site) it uses 0.040 x 10min/60min= 0.007kwh, so you've saved maybe 0.013kwh. At 25 cents/kwh you've saved maybe 1/3 of one cent.

You'd have to bake one batch of cookies a day for a full year (checking it 5 times every time, with a fully open door each peek not just a crack) for that to add to a buck. At the national average price of electricity it's maybe 50 cents, and if it's a gas oven, less. That's the order of magnitude of the "....large amount of energy..." you'd be saving by not opening the oven 5 times every time you bake a batch of cookies.

If you then calculated the reduction in heat load on the heating system or increased load on the cooling system the net energy use would be even lower still, in most climates.


79.
Sep 24, 2015 1:13 PM ET

Darn it, Dana
by Martin Holladay

There you go again, Dana -- puncturing the balloon of a blogger who wants to "just imagine" by suggestion calculations.

Hmmm... maybe if our schools weren't arresting 9th graders for bringing their science projects to school, we might have more bloggers who knew how to calculate.


80.
Sep 24, 2015 2:13 PM ET

Bloggin's a 'ritin' exercise...
by Dana Dorsett

...an' calculatin' is 'rithmetic.

Some go to Harvard, others M.I.T., but this one doesn't take hard-math. A smart 5th grader good at "word problems" might have been able to come up with the correct order of magnitude with only a small amount of guidance.

Maybe I just don't have a good enough imagination to play in the blogger leagues! :-)

The kid in TX wasn't the first (and probably not the last) case of paranoia over breadboarded electronics- an M.I.T. sophomore was arrested for wearing a home made blinky-blinky-LED pin on her sweatshirt at Logan Airport in Boston several years ago:

http://boingboing.net/2007/09/21/mit-student-arrested.html

http://tech.mit.edu/V127/N40/simpson.html

D'ya think that if it was part of a weapon she might have hid it UNDER the hoodie?

http://i2.wp.com/boingboing.net/images/cfa4827569_20070921device3.jpg?w=315

One has to wonder if the TX kid's name had been Alex instead of Ahmed the local school & legal authorities' presumptions / perceptions of what the thing was might have been different. I don't blame him for not going back to that school.


81.
Dec 10, 2015 10:11 AM ET

Stuffing the fridge.
by Sherwood Botsford

1. Fridge/Freezer.
Whether it will make a difference depends on how often you go to the fridge, and how long the door is open. A fridge or upright freezer that is opened twice at breakfast and 3 times at supper, you are probably right.

A typical north American fridge is 18-22 cubic feet. Call it 18. Let's suppose that it normally has 6 cuft of stuff in it, and that clever use of water bottles, rectangular milk jugs can get it up to 12. So there is 6 cuft of air inside. Let's suppose that 5 cuft of this changes with every door open and shut operation.

With the unstuffed fridge these numbers are 12 and 10.

5 cuft is roughly 1/7 cubic meter. A cubic meter is 1.25 kg. Air has close to the same specific heat as water per kg. So to cool a cubic meter of air from 70 F to 40 F will take 1.25 * 2.2 * 30 BTU = about 80 BTU. And since this is BoE math, we'll call a BTU a kJ. So 80 kJ. A kWh is 3600 kJ So opening the reefer door 7 times a day for 45 days = 1 kWh. So we're talking 8 kWh/year.

Except 7 times? Really. Me:
Morning coffee: open fridge, grab creamer, shut fridge. Pour creamer. Open fridge replace creamer close fridge. I typically do 5 cups of coffee a day.
That's 10
Breakfast cereal. Often two separate operations for milk and for creamer again.
Now we are at 14.
Lunch: Cheese, mayo, mustard. Often 2 openings each.
Now we are at 20.
My wife isn't much different, so we are at 40 before we get to supper.

I don't think that 60 is an unrealistic count. I suspect that families with kids are worse. Now we are talking about 64 kWh per year. At 8 c/kWh (My differential rate -- I have a $60 month line charge) this is close to 5 bucks. For people paying 16 c/kWh this could be as much as $10/year!

The upright freezer isn't opened as often, but the air exchange is more thorough (You often have to look for something.) and the delta T is twice as large.

On the flip side of this: A crowded fridge is open longer to get anything not in front. And maybe my 83% air change on opening is too high.


82.
Dec 10, 2015 10:18 AM ET

Ceiling Fans
by Sherwood Botsford

In a cathedral ceiling we run a ceiling fan 24/7/365 on low. 12 w. We heat with two wood stoves, and the heat tends to stratify.

In the the den where the other stove is, we do reverse the fan in winter. (Sucking up, not blowing down) I don't see it as making any difference in terms of heat distribution, but the perception of 'drying eyes' for people near the fan is far less. In summer when I come in from the field, I will often stand under it and switch it to high for a few minutes.

The backup heating system is hot water baseboards.


83.
Dec 10, 2015 10:34 AM ET

Unplug your second freezer?
by Sherwood Botsford

If I did that, the meat would spoil!

Unplug the second freezer if it's empty, or only used to keep beer cool.

We have two freezers, one upright, used for anything that stacks (wire basket at the bottom for bags of veg) and one chest freezer. The latter is 75% full on average for the year, hitting a minimum before the fall fractional cow comes home. The former is typically about half full. It's fullness is adjusted by things like bags of whole wheat flour which don't require freezer space, but which go rancid if stored for long periods at room temp.

Two freezers for only two people? It's 75 km to the nearest good grocery store. I figure that the Subaru costs us $30 for a round trip. $30 is 375 kWh. A storage unit that saves us 3 trips a year to town (based on an average of 100 kWh/month) is a win. This also allows us to get groceries once a month on First Tuesday (15% off) with a more local trip between for milk and fruit.

One good tip: Put your freezer collection on the porch. While fridges act erratic in unheated spaces, I've had 4 different freezers that lived on the breezeway or on a covered deck. Here we have a strongly net heating climate. The house is cooler than the porch only in afternoons on a warm sunny day. And in winter, the freezer may not come on for days at a time.


84.
Dec 10, 2015 10:45 AM ET

Response to Sherwood Botsford
by Martin Holladay

Sherwood,
Good for you for doing the math to show that the energy needed to run your freezers is less than the energy that would have been used for extra shopping trips with your Subaru. That's the kind of calculation that more homeowners should be performing when making energy decisions.


85.
Dec 10, 2015 10:56 AM ET

Closing curtains at night.
by Sherwood Botsford

While this will not stop convection on the inside of the glass, I would expect it to make a difference to radiation. This assumes that the curtains are close to opaque. If the temp on the window side of the curtains is the average of the window glass temp and the room temp, the radiation looses will be cut by somewhat more than half. (Radiation is proportional to the 4th power of absolute temperature.) Drapes with a back side of aluminum coated mylar should do even better.

With a 100 F differential, a window acting like a black body cavity has a net radiation outward of about 75 w/m2 or about 25 BTU/ft2/hr. Given that an R2 window in this same situation will fllush 50 BTU/ft2/hr, cutting your radiation loss in half isn't that big a deal. Even cutting ALL of it is still only saving 1/3 of your losses. And even here 100 degree differentials aren't THAT common. Because of that 4th power law, at a 50 degree delta T you don't have nearly the loss.


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