cooling

Choosing a Base Temperature for Degree Days

Posted on March 29,2015 by ab3 in cooling

Degree days are a combination of time and temperature. We looked at their uses and where they come from in Part 1 of this series, and now it's time to go a little deeper. The temperature enters as a temperature difference, ΔT (delta T), but it's not the ΔT between inside and outside of the building. It's the difference between the outdoor temperature and the base temperature. But what is this thing called base temperature?

Why Is My House So Hot?

Posted on March 29,2015 by ScottG in air conditioning

When Jeff Watson realized that the insulation on his attic floor was rated at R-11, he did what any energy professional would have suggested: he added more insulation. He air sealed the attic floor, added ventilation baffles where necessary, and blew in a thick layer of R-60 insulation. But he isn't entirely satisfied at the results. "As expected, the temperature in the house doesn't fluctuate as much," Watson writes in a Q&A post at GreenBuildingAdvisor. "However, I feel as if I'm using AC more.

High-Tech Ceiling Fans for Low-Tech Cooling

Posted on March 29,2015 by AlexWilson in Ceiling fan

Winter has barely ended in Vermont, but as I write this the forecast is for 82 degrees tomorrow. This makes me think about strategies for keeping cool in the months ahead. I’m looking forward to trying out the high-tech ceiling fans we installed in our two upstairs bedrooms. I’ll get to those fans in a minute, but first I’ll explain why I like ceiling fans so much.

How to Buy an Energy-Efficient Ceiling Fan

Posted on March 29,2015 by ab3 in air flow

A little over a decade ago when I was building a house and buying a bunch of ceiling fans, it wasn't so easy to figure out which fans were energy efficient and which weren't. That's not the case anymore because every ceiling fan now has a label on the package that tells you how much air movement you can expect for each watt of electricity you put into the fan.

A Post-Passivhaus Paradigm for Energy-Efficient Design

Posted on March 29,2015 by user-1018844 in cooling

Last night, I enjoyed an intense conversation with my friend Bill Updike. Bill, who has been closely following the developing partnership between PHIUS and Building Science Corporation, is the green building specialist at the Washington, D.C. Department of the Environment. We were talking about cost-effective energy-efficient design, and Bill tossed off a comment that the key to any design — at least in our mixed-humid climate here in Maryland — should be the latent load of the building. When he said that, my mind lit up like a pinball machine showing three cherries.

Does More Wall Insulation Reduce Cooling Costs?

Posted on March 29,2015 by user-1048334 in cooling

Adding insulation reduces heat flow. That’s what insulation does. But how much does wall insulation impact the heat flowing into your house during the summer? And is adding wall insulation the most effective way to reduce your cooling bill?

Ceiling Fans Are Evil

Posted on March 29,2015 by CarlSeville in Ceiling fan

I can’t count the number of times I have walked past a neighbor’s home and seen the porch ceiling fans running with no one there to appreciate them. All the fans are doing is wasting electricity and contributing a little heat to the outdoor air. I am tempted (although I have never acted on the impulse) to pull the chains and turn the fans off or leave the neighbors a note.

An Epidemic of Duct Disease and Enclosure Problems

Posted on March 29,2015 by ab3 in AC

When an air conditioner breaks down in hot weather, homeowners reach for their phone. The HVAC company then sends someone out to the home with the immediate goal of getting the AC running again so the occupants will cool off. The thing is, though, that most homes have problems that run deeper than the cause of the broken air conditioner.

A 3-Ton Air Conditioner Will Rarely Give You 3 Tons of Cooling

Posted on March 29,2015 by ab3 in ACCA

Today I'm going to give you three reasons why your 3 ton air conditioner isn't really a 3 ton air conditioner. Of course, there are more than three reasons, starting with the fact that it's not 3 tons in weight. That unit refers to cooling capacity and harkens back to the days of ice.

Climate-Specific Air Conditioners

Posted on March 29,2015 by user-756436 in air conditioner

If you live in a humid climate (for example, in Florida), you need an air conditioner that does a good job of dehumidification. But if you live in a dry climate (for example, in Nevada), dehumidification is almost irrelevant, because the outdoor air is so dry. In Nevada, all you need is an air conditioner that lowers the temperature of the air in an energy-efficient way.

A Chat With Henry Gifford

Posted on March 29,2015 by user-756436 in cooling

Most builders and designers involved with green building have heard of Henry Gifford. Energy efficiency experts admire his deep knowledge of heating systems and his straight talk about the unacceptably high number of HVAC problems in run-of-the-mill new buildings in the U.S. At the headquarters of the United States Green Building Council (USGBC), on the other hand, he is something of a pariah — due in part to his 2010 lawsuit that accused the USGBC of making “deceptive marketing claims.”

The Difference Between Air Conditioners and Dehumidifiers

Posted on March 29,2015 by user-1048334 in air conditioner

There’s a great Patton Oswalt bit where he contemplates meeting George Lucas in 1996 (gotta love the oblique intros). After slobbering over the original Star Wars trilogy and just about suffering an aneurysm over a possible new trilogy, his enthusiasm tapers off dramatically. He finds out what the new movies will be about, namely all the background filler behind his favorite characters and moments — which he hasn’t the palest interest in. To paraphrase, we don't care where the stuff we love comes from; we just love them.

The Magic of Cold

Posted on March 29,2015 by ab3 in air conditioner

With the recent heat wave that set all kinds of records across the US, including an all-time high of 106° F here in Atlanta, air conditioning has become quite the topic of conversation. Why, just yesterday I overheard two little old ladies* on a park bench debating thermostatic expansion valves versus capillary tube metering devices — and almost coming to blows over it!

Keeping Cool

Posted on March 29,2015 by AlexWilson in Ceiling fan

Welcome to summer. Burlington, Vermont hit a record 97°F the other day, and my place in West Dummerston reached 93°, with high humidity. What’s the best way to stay comfortable in weather like this — assuming that you’re not using mechanical air conditioning? First, it’s important to understand that the goal isn’t really about temperature; it’s about comfort. Some very simple strategies can help you remain comfortable even with high air temperatures.

Window-Mounted Air Conditioners Save Energy

Posted on March 29,2015 by user-756436 in air conditioner

Window-mounted air conditioners (also called room air conditioners) aren’t particularly efficient; the best available models have an EER of about 10 or 11. Central air conditioners (also called whole-house air conditioners or split-system air conditioners) are significantly more efficient; it’s possible to buy one with an EER of 14 or even 15. So if you care about energy efficiency, you should use a central air conditioner, not a window air conditioner — right? Well, not necessarily.

Calculating Cooling Loads

Posted on March 29,2015 by user-756436 in air conditioning

A few decades ago, residential air conditioning was very rare in colder areas of the U.S., and cooling load calculations were usually unnecessary. These days, however, new U.S. homes routinely include air conditioning equipment, even in Minnesota, so most U.S. builders are faced with the need to calculate cooling loads.

Resilient Design: Natural Cooling

Posted on March 29,2015 by AlexWilson in AC

Over the past month and a half, my blogs been focusing on resilient design — which will become all the more important in this age of climate change. Achieving resilience in homes not only involves keeping them comfortable in the winter months through lots of insulation and some passive solar gain (which I've covered in the previous two blogs), it also involves keeping them from getting too hot in the summer months if we lose power and our air conditioning systems stop working.

Using Ceiling Fans To Keep Cool Without AC

Posted on March 29,2015 by user-756436 in AC

When I was a young backpacker traveling through India, Sri Lanka, and Thailand in the 1970s, I couldn’t afford air-conditioned hotels or restaurants. In these tropical conditions, I became quite accustomed to the benefits of Casablanca-style fans.

7 Steps to an Energy-Efficient House: 5. Mechanicals

Posted on March 29,2015 by Betsy Pettit in air conditioner

Editor's introduction: With energy prices rising again, many homeowners are planning energy-efficiency improvements to their homes. But most people are unsure of where to begin, and even seasoned builders don’t always know which priorities should rise to the top of the list. Betsy Pettit, an architect at [Building Science Corporation](http://www.buildingscience.com), recommends starting where you can get the most bang for the buck. Step 5: Replace your furnace, boiler, or water heater

Air Conditioner Basics

Posted on March 29,2015 by user-756436 in air conditioning

What does a Vermonter know about air conditioning? I live so close to the Canadian border that half of the radio stations are in French. If my house needs cooling, I just let the fire in the wood stove die down. When I first began reporting on air conditioning topics over a decade ago, I felt out of my element. Impelled by the certainty that there’s no such thing as a dumb question, I’ve managed over the years to badger a few air-conditioner experts, all of whom contributed to my education. So now I finally know the difference between an evaporator coil and a condenser coil.

Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!

Syndicate content