How Energy Efficient Is Your Ceiling Fan?
I was in one of the big box home improvement stores yesterday and thought I'd take a look at ceiling fans while I was there. Ten years ago when I was building a house and buying a bunch of ceiling…
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Does a Geothermal Heat Pump Count as a Renewable Energy Source?
Here's another rant that goes in my Drives Me Crazy category of articles. I'm in good company, too. Green Building Advisor ran an article this week about making the choice between an air-source heat pump and a ground-source (aka geothermal)…
How to Grade the Installation Quality of Insulation
Six years ago, RESNET published a major revision of the HERS Standards, called...wait for it: the 2006 National Mortgage Industry Home Energy Rating Systems Standards. One important new feature in the standards was the grading of insulation installation quality. Before…
A Sword through the Ribs of the Building Envelope
The title of this article refers not to the two framers charging the house with a large timber but to the framing timbers already installed above the porch. Home designers, builders, and framers aren't used to thinking about the building…
The Easy Way to Convert between Celsius and Fahrenheit
Converting between temperatures on the Celsius and Fahrenheit scales is easy. I've been doing it in my head for over a decade now. Yeah, I know I'm a weirdo, using the metric system here in the US when no one…
You Don’t Need a Vapor Barrier (Probably)
If there's one building science topic that confuses more people in construction than any other, I think I'd say it's the purposes and properties of the various control layers. I'm talking about the materials that are meant to control the…
Why I’m Not a Fan of Positive Pressure Mechanical Ventilation
We want our homes to be airtight. It saves energy. It helps keep water vapor from getting into places where it can cause problems. It keeps bad air from moldy crawl spaces and contaminated garages out of the house. It…
Two Open Doors to the Attic – A Building Science Nightmare
Take a look at this first photo. If you've got any building science training at all, I really don't need to say anymore. Sure, I could fill you in on some of the details, but I'm betting you already know…
A Fun Visualization of Air Leakage During a Blower Door Test
In our last home energy rater (HERS) training class, we saw something very interesting on one of our field visits. We were doing a Blower Door test on a new house, and one of the bedrooms upstairs had plastic taped…
The 3 Rules of Air Leakage (Plus a Bonus!)
Here's the thing. If you have anything to do with houses (home builder, remodeler, HERS rater, trade contractor, homeowner...), you probably ought to understand these three fundamental principles of air movement. Then you'll have a better chance of knowing how…