Air has weight. Air can move things, like giant wind turbine blades. Air can also crush things. I first got to see the power of air in my introductory physics class in college. The professor, Dr. Jeffrey Trahan, showed the…
If you've ever seen frost in the attic in winter, it's pretty to easy to understand why it's happening. It's the same thing that causes morning dew on the grass, frost on the exposed half of my car, or water…
It's that time of year again. The cold weather has begun here in the Northern Hemisphere, and people are talking about raising the humidity of the indoor air. I'm certainly no fan of bone-dry air, having experienced too much of…
Where to put the air barrier may seem obvious, but this question has many dimensions…literally. Let's look at the question of air barrier location from three perspectives. First, building assemblies are three-dimensional. The air barrier can go on the inside,…
The COVID-19 pandemic has changed a lot of things, including my view on higher ventilation rates. A few years ago, Joe Lstiburek of Building Science Corporation pushed hard for lower ventilation rates. He believed ASHRAE's residential ventilation standard (62.2) resulted…
Building enclosure control freaks know that a good exterior sheathing can make a huge difference in performance. Controlling the flows of moisture, air, and heat requires good control layers. A lot of materials and methods will get you there, but…
Sizing a heating or cooling system should start with an assessment of the heating or cooling load. Nowadays, we know the physics behind heat transfer, so we can come up with fairly accurate predictions of how much heating and cooling…
Let's talk about one of my favorite subjects: air. Because of the global COVID-19 pandemic and the novel coronavirus (SARS-COV-2) that spreads it, the indoor air quality (IAQ) community—researchers, mediators, manufacturers, bloggers, groupies—is having a moment. This must be the…
Have you ever lived in a home where you just couldn’t feel warm even though you had the heat cranked way up? How about one where you have to turn up the volume on the TV when the air conditioner…
Ever have the smell of your fireplace inside your home? It's not uncommon. Here's a question I got from a reader named Rob last month:We always have a smoke smell from our fireplace, more on some days than others. I…