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Energy Solutions

Changing Behavior to Save Energy

Follow your grandmother’s advice: turn down the thermostat, turn off the lights, and take shorter showers

I’ve told you a thousand times — turn off the light when you leave the room! Remembering to turn off the lights is easy and it saves a lot of energy.
Image Credit: Alex Wilson

We live in a world of gadgets and stuff. When it comes to saving energy, we look to high-efficiency light bulbs or dishwashers. Or we use the advanced weatherstripping to seal our windows or add insulation in our attics. And hopefully we’ll look at fuel-economy ratings when shopping for our next car.

Those are important things to be doing — and we should continue paying attention with all of our purchases. But we should also recognize that behavior is a big part of our overall energy consumption.

The fact is, you can build two identical homes, right next to each other — with the same insulation levels, the same windows, the same appliances, and the same lighting — and the energy bills for those homes can differ by a factor of two, because they are operated differently.

Operating houses in a more energy-efficient manner

So how can homeowners modify the energy performance of their homes? There are lots of ways — many of them so obvious one might be tempted not to even list them. But we sometimes overlook the obvious.

So here’s a starter list — all of them costing nothing. I’m hoping you will comment at the end of this blog with your own suggestions of other ways to reduce home energy consumption based on how you operate your home — or what you recommend to your clients.

In an upcoming column, we’ll take to the road and look at how decisions we make affect our energy use in getting around.

Turn off the lights

As I write this, I notice that we have two kitchen lights on that aren’t really needed. I’m not without guilt when it comes to failing to carry out this obvious energy-saving strategy.

Some of us want to rely on special devices to ensure that we don’t waste lighting energy — occupancy sensors that turn out lights automatically when people leave a room — but we don’t need anything new to make this happen. Creating a culture of paying attention is the easiest solution, and it doesn’t cost anything and doesn’t break down.

Close off unused portions of your home

Reducing the square footage of a home that’s being heated can save a lot of energy. If you have a couple guest rooms that aren’t used on a regular basis, consider closing them off and adjusting your heat distribution system to deliver less heat to those spaces.

With forced-air heat, this involves closing the air-supply register (which results in more warm air delivery to other rooms). If you have hydronic heat (baseboard hot water), there’s usually a long metal flap on baseboard convectors that can be closed to block the release of heat from these units (and keep most of the heat in the hot-water pipe to reach the next room). Neither of these adjustments blocks off all of the heat to these unused rooms — and that’s usually a good thing, as you don’t want to rooms to get too cold — but these adjustments can save a significant amount of energy.

Turn down the heat

How you set your thermostats can have a huge impact on your heating energy use. Set-back and programmable thermostats help with this (and I strongly recommend them), but you can also adjust thermostats manually on a daily basis. A common rule-of-thumb (that may or may not be very accurate) is that for every degree Fahrenheit a thermostat is turned down, savings of 2% in total heating energy use is realized.

So for example, if you keep the house at a constant temperature, reducing the setting from 72°F to 67°F (five degrees) would reduce your heating bill by 10%. Or, a nighttime (8-hour) setback from 72°F to 62°F would reduce your heating bill by about 7% (20% divided by three since the setback is only for eight hours).

Advanced programmable thermostats allow multiple temperature settings during a 24-hour period so that the temperature can be lowered during the day when homeowners are out of the house and again at night when they are sleeping. These thermostats typically allow a different weekend setting. (Note that with radiant floor heating, setback may not be recommended due to the thermal flywheel effect of the concrete slab; get advice from the installer about operation.)

The same setback argument applies in the summer if you use air conditioning — though in reverse. You can save a lot of electricity use for air conditioning by raising your thermostat setting.

Operate storm windows properly

If you have storm windows, make sure they’re properly installed in the fall. With triple-track models, make sure the glass panels are properly in their tracks and all the way closed.

With old-style wooden storm windows, make sure they’re all back on the windows by the time temperatures drop and ventilation is no longer needed. To simplify the seasonal adjustments with our wooden storm windows, we only remove the storms from those windows we use for ventilation. The other storm windows stay up all year.

Take shorter showers

Heating water is often the second-largest energy use in a home, and in a highly insulated home it’s not uncommon for it to be number-one. Our largest use of hot water is often showering, so by taking shorter showers significant savings can be realized. No big surprise there.

Another showering habit that will save energy is to reduce the flow when shampooing or shaving. For this reason, I prefer shower valves that have separate controls for both temperature and volume so that the flow can be adjusted without affecting the temperature mix. If you have a single lever that controls only the temperature, you can install a showerhead with a cut-off valve that reduces the flow to a trickle, or a valve that’s installed between the stem and showerhead.

Wash clothes with cold water

Another simple and fairly obvious strategy for saving energy is to switch to cold-water washing. We’ve been washing most of our clothes in cold water for several years now, though we still use hot or warm for certain loads. Use a detergent optimized for cold-water washing.

You can also save energy by hanging clothes outside. Some people I know line-dry their laundry, but then put in the dryer for a few minutes to fluff it and remove the stiffness from outdoor drying.

Operate your dishwasher with full loads

Dishwashers consume energy both by using hot water and from the heated drying cycle. If you use the dishwasher less frequently by only running it when it’s all the way full, you’ll save energy.

You can also turn off the electric-heat dry function. With the several dishwashers my wife and I have owned over the past 30 years, I don’t think we’ve ever used the electric drying option.

Other no-cost ways to save energy

I’ve provided here just a few examples of simple ways to save energy in our homes simply by changing the way we do things. There are lots of other examples having to do with cooking, refrigerators, how we dress, and using fans instead of air conditioning. What are your favorite strategies?

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also recently created the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.


  1. JoeW519 | | #1

    Kids learn by watching and through expectations placed on them -- my dad, raised in the Depression, had two mantras, one for lights (If you can turn it on, you can turn it off) and one for doors (You opened it; you shut it). He deducted from allowance and pay (for chores) for each infraction.

    In our neighborhood, outside lights provide security. But there's no reason they have to be on all night -- trigger them with motion sensors.

    Shut the refrigerator door; shut off its "humidity" detector (which heats the case so condensation doesn't form) and wait to see if condensation forms, then use it for just so long as it takes.

    You're running water to clean, not for a massage, nor as a water feature. Just shut it off.

    If you garden, invest in drip hoses.

    In my climate, adjust the ceiling fan before you turn on the A/C. Leave the windows shut to keep out the humidity. If you want fresh air, go outside.

    Yes, I'm cranky, lol. Merry Christmas.

  2. user-946029 | | #2

    Math question
    Is there a math error in the 2nd paragraph of the section titled "Turn Down The Heat"? I understand 20%/3 = 7%, but where did the 20% come from? I thought the savings, per the previous sentence, was 10%.

    Maybe I'm confused.

  3. GBA Editor
    Martin Holladay | | #3

    Response to Mike Collignon
    Here's my understanding of the underlying math:

    Rule of thumb: Each degree F reduction in the thermostat setting for 24 hours a day results in a 2% savings in your heating energy bill.

    A setback of 10 degrees F would therefore result in a 20% savings if the setback lasted for 24 hours a day. If the setback only lasts for 8 hours per day, then your savings are about 7% (about 1/3 of 20%).

    This is rough-and-ready "napkin math." Take it with a grain of salt.

  4. Alex Wilson | | #4

    Set-back savings
    Yes, Martin is correct on the math--and correct that we should take that with a grain of salt. Those assumptions are for an average house. With a highly energy-efficient house, I think the effect would be quite different.

  5. user-1002005 | | #5

    other suggestions
    Turn the heat down a couple of degrees every month and every year - you will get used to 63 degrees pretty easily (though slowly - it might take a couple of years). Wear long underwear and a sweater all the time.

    Turn the heat down to 50 degrees at night.

    Keep your refrigerator and freezer full.

    Slowly train yourself to get used to lower light levels indoors.

    Go to bed earlier.

    Turn the TV and computer off when you're not looking at them.

    Use power strips for computers, TVs, etc. Keep them off when you're not using the device.

    Don't shower if your hair isn't greasy: wash yourself at the sink with a washcloth.

  6. user-946029 | | #6

    I see where I made my error. I read the second set of numbers as 72-67, not as they were written (72-62). Sorry about that.

    That's what I get for speed reading.

  7. user-980774 | | #7

    My first "super" insulated
    My first "super" insulated house twenty years ago, the clients had very high utility bills. I went to trouble shoot the problem and they had the A/C set at 70 and the heat set at 69, one or the other was running most of the time. I realized I needed to "train" clients and discuss expectations.

    In a typical two story with with master bathroom up and DHW in the basement, washing your hands with hot water uses 3 plus gallons of hot water. A little bit of thought and you realize soap and cold water works just fine.

    This time of year when doing my evening walk, I am amazed at the number of houses with bright lights in every room in the house. I've never seen the need to light rooms that are not in use.

  8. Expert Member
    Dana Dorsett | | #8

    Myth busting about closing off registers and setbacks...
    Closing off vents to unused rooms INCREASES rather than decreases energy use, as counter-intuitive as that might seem. Increased duct pressures and lower system balance driving higher whole-house infiltration rates is the culprit. Air sealing ducts & house may lower the magnitude, but not the direction of the change in energy use.

    From :


    According to a 2003 study by the Lawrence Berkeley National Laboratory:

    "Closing registers in forced-air heating systems and leaving some rooms in a house unconditioned has been suggested as a method of quickly saving energy for California consumers. This study combined laboratory measurements of the changes in duct leakage as registers are closed together with modeling techniques to estimate the changes in energy use attributed to closing registers.

    "The results of this study showed that register closing led to increased energy use for a typical California house over a wide combination of climate, duct leakage, and number of closed registers. The reduction in building thermal loads due to conditioning only a part of the house was offset by increased duct system losses, mostly due to increased duct leakage. Therefore, the register closing technique is not recommended as a viable energy saving strategy for California houses with ducts located outside conditioned space.

    "The energy penalty associated with the register closing technique was found to be minimized if registers farthest from the air handler are closed first because this tends to only affect the pressures and air leakage for the closed off branch. Closing registers nearer the air handler tends to increase the pressures and air leakage for the whole system.


    I couldn't find the original LBL study online ("Register Closing Effects of Forced Air Heating System Performance." Walker, I S. ) but it's out there, and widely referenced in other academic research on the topic.

    The overnight thermostat setback issue is also not universal. With modulating heating systems such as ductless mini-splits or modulating condensing boilers under "outdoor reset" control, overnight setbacks force the systems to run at dramatically lower efficiency during the recovery ramp periods, erasing any savings, and sometimes significantly increasing total energy use. (This is not the case with most condensing gas furnaces or non-condensing hydronic boiler systems.)

    Only with setback periods much longer than 8-10hours would any energy be saved with a mini-split air source heat pumps, since running at max-power during a recovery period they only run at 50-70% the efficiency as when modulating with load. This varies with outdoor temp and actual overnight load, but a 30-50% hit in efficiency is a reasonable approximation for most real-world installations. See figure 5 on p.10 (p.18 in pdf pagination) of this document:

    The lower heat loss due to the lower temperature in the house over night is nowhere near as big a gain as the hit in recovery efficiency when warming it back up- it's a net loss. "Set and forget" is a much better strategy with these systems unless you're taking off for the weekend.

  9. GBA Editor
    Martin Holladay | | #9

    Response to Dana Doresett
    I agree with you. GBA already reported on that study in a previous article: More Energy Myths.

  10. JonathanTE | | #10

    Use winter to pre-cool leftovers
    Another thought... before putting leftovers into the refrigerator, let them cool down. We are in the happy situation of living in a quiet, small town, so we will put a pot of hot leftovers on the stoop in cooler weather to chill it before moving it to the refrigerator. (I wouldn't have done that when I used to live in Washington DC, even assuming I had the get-up-and-go to walk down 5 floors to the apartment building front door.) When the food in question has been cooked and is still in our pressure cooker (which has a locking lid), we'll just leave it on the stoop all night in winter. The basically air-tight lid prevents odors from attracting animals--at least, we've never seen evidence of animals trying to get in.

    Pressure cookers! If you have one and don't use it, then that there is a great behavior change to aim for. They'll save you energy while you cook, and as we've learned with the trick above, save you more when the food is finished and ready to store.

  11. JonathanTE | | #11

    Fill dead air space in freezers/refrigerators
    A comment above recommended keeping a full refrigerator or freezer. If you find you often have a fair bit of free space, consider downsizing your fridge/freezer. In the meantime, you can fill empty space with either jugs of water, empty shoe boxes or similar, or bags full of styrofoam peanuts that you otherwise have no use for. All of them help by preventing large volumes of chilled air from falling out of the appliance (assuming an upright model) when you open the door, so that the appliance doesn't have to chill new, warm air. It's possible that the jugs of water help the most by adding a thermal mass advantage.

    We have a second freezer in the basement which gets loaded up in autumn with garden surplus. As the winter goes by and it starts to empty out, in go the shoe boxes to take the place of the veggies.

    UPDATE: oops. I just followed Martin's link and (re)read his More Energy Myths post from a year ago. It lists filling up refrigerators as one of those energy saving myths. Alas.

  12. JoeW519 | | #12

    reply to Jonathan
    Letting the weather be your friend when it's as cool outdoors as it is in your refrig makes good sense but the notion of pre-cooling when warm food is brought down to room temp on the kitchen counter can become a medical issue, as once the food holds a temp that will allow bacteria, etc to flourish, you may create intestinal issues, maybe serious!

    I once had a neighbor raccoon decide the goodies cooling on my porch were really appetizing .... but that's another story.

  13. watercop | | #13

    Thermostat setback math, dishwashers, clothes dryers
    I agree with Dana's comments as to the efficiency of various types of heating systems operating at higher outputs during recovery periods. Some systems are more efficient if this is avoided, others, particularly constant output systems, do better with long on-cycles, somewhat like highway driving.

    Then there is the issue of savings from the setback itself. Setback only saves after the home has partly or wholly cooled down to the setback temperature, reducing the temperature gradient across windows, doors, and exterior walls. A tight house may not cool much during the first few hours of a setback, so will not deliver much savings.

    A note on dishwashers - many have a "quick wash" cycle that takes just 30-40 minutes and uses far less energy than a full 90+ minute cycle. Ours delivers satisfactory results with the quick cycle if the machine is 2/3 - 3/4 full. In other words, it'll clean a half load for 1/3 energy, so we come out ahead using that mode.

    OTOH, clothes dryers seem to work differently. I'm gathering experimental data on loads of laundry - I have a TED monitoring channel on our clothes dryer and I'm using a refrigerant cylinder scale to weigh wash loads before and after drying so as to calculate pounds of moisture removed per kiloWatthour.

    Preliminary data suggests the dryer runs most efficiently (upwards of 2.0 lbs / kWh) with fairly heavy loads using the "casual" (between "normal" and "delicate" temperature profiles). A couple of times I've combined two medium sized wash loads in a single dryer cycle, which has yielded best efficiency without significantly lengthening drying time or lint production.

  14. sunstone | | #14

    Would using task lighting
    Would using task lighting instead of lighting up the entire room be more efficient?

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