The most recent blogs at Green Building Advisor

The Achilles’ Heel of Zoned Duct Systems

Posted on August 6, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Last week I wrote about what happens when you try to save energy by closing air conditioning registers in unused rooms. In the end, I recommended not doing it because you won’t save money and you may create some big problems for yourself, like freezing up the coil and killing your compressor.

At the end of the article, I mentioned that zoned duct systems do close off registers, and that doing so can be OK with the right kind of equipment and design. But there’s one thing often done in zoned duct systems that’s rarely done well.

Choosing Kitchen Appliances for a Passivhaus

Posted on August 5, 2014 by Andrea Lemon in Guest Blogs

After living in our house for 1½ years, I finally have enough distance to evaluate the many decisions that went into building it. I plan to write a series of "Hindsight" posts, speaking frankly about what worked and what we'd do differently if we had to do it all over again.

To start the series, I'm going to keep it simple and talk about our kitchen appliances. Don't worry, I'll cover all the hairy Passivhaus details eventually, but I'll start at the shallow end.

Running Our House on Prius Power

Posted on August 4, 2014 by Paul Honig in Guest Blogs

On Sunday morning June 30th, we experienced our first prolonged power outage since moving in to our new passive house in Connecticut. A tree came down on one of the power lines around the corner and power was out for about six hours. It was time to see our inverterDevice for converting direct-current (DC) electricity into the alternating-current (AC) form required for most home uses; necessary if home-generated electricity is to be fed into the electric grid through net-metering arrangements. in action — the inverter that we bought from Converdant Vehicles to turn our Prius into a backup generator.

A Canadian Editor Questions Passivhaus Dogma

Posted on August 1, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Today's brief blog — a departure from my usual practice of writing in-depth articles — was inspired by a recent editorial by Richard Kadulski, the editor of a Canadian newsletter called Solplan Review.

Is It OK to Close Air Conditioner Vents in Unused Rooms?

Posted on July 30, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Your air conditioner, 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., or furnace probably uses a lot of energy. Heating and cooling makes up about half of the total energy use in a typical house. For air conditioners and heat pumps using electricity generated in fossil-fuel fired power plants, the amount you use at home may be only a third of the total.

Multifamily Green Building Certification Still Has Issues

Posted on July 29, 2014 by Carl Seville, GBA Advisor in Green Building Curmudgeon

Much of my work these days involves certification of multifamily buildings, and, thanks to a boom in apartment construction, my partner and myself are staying occupied.

The one major contrast from single-family residential work, with which I am most familiar from my days as a contractor, is the long lead time. I still find it amusing that I sign a contract, have an initial start-up meeting with the developer and contractor, and often don’t see the project for another year or more, when the builder is ready for our insulation and air-sealing inspections.

Heat Losses Are Way More than Planned

Posted on July 28, 2014 by Scott Gibson in Q&A Spotlight

Bob Holodinsky was hoping for a better outcome from the heat loss calculations he received for his new Peterborough, Ontario, home — calculations that appear to have upset his plans for heating with a ductless minisplit. "I thought I was on the right track," he writes in a Q&A post at GreenBuildingAdvisor, "but now I am not so sure."

What Should I Do With My Old Windows?

Posted on July 25, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

If you’re trying to lower your energy bills, you have probably plugged many of your home’s air leaks and have added insulation to your attic floor. Now you may be wondering, “What should we do about our old windows?”

Unfortunately, there is no clear answer to this question. Sometimes it makes sense to leave old windows exactly the way they are. Sometimes it makes sense to repair the windows’ weatherstripping and add storm windows. And sometimes it makes sense to replace old windows with new energy-efficient windows.

A Call for Guest Blogs

Posted on July 24, 2014 by GBA Team in Green Building Blog

GBA loves guest blogs. Our readers are smart. Many of you post long, thoughtful comments on GBA every day. So it's time for some of you to send us a guest blog. We'd love to publish what you have to say.

What's a guest blog? Sometimes it's nothing more than three or four paragraphs and a good photo.

Did you see something funny at a job site today?

Did you drive past an ugly house yesterday?

Are you an inspector who can't believe what you see?

Did you just invent a great detail?

How Duct Leakage Steals Twice

Posted on July 23, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Duct leakage is a big deal. It's one of the top three energy wasters in most homes (air leakage and cable TV set-top boxes being the other two). Researchers at Lawrence Berkeley National Lab found that duct systems leak on average about 10% of the supply air they move and 12% of the return air. (Download pdf and also see Dana Dorsett's comment below, #1.) In far more homes than you might suspect, the main culprit is a disconnected duct, as shown in the photo at right, but a typical duct system has a lot of other leaks, too.

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