Can Cold Surfaces Wring Moisture From Dry Air?
Cold air is dry air, right? Think about the humidity in your house in winter compared to what it is in summer. If you're in a humid climate, it's going to be drier in winter. Even in dry climates, it's…
attic
A Frosty Heat Loss Puzzler
My house exhibits an interesting phenomenon on occasion. A lot of people who understand building science sometimes jump to the wrong conclusion when they see it. Hey, I did the same thing myself at first, too. The puzzle lies in…
Is Wind Washing Reducing Your Insulation R-Value?
You'd think that after more than 12 years and a thousand-plus articles, I'd have mentioned all the major building science terms by now. Yet, here we are. I just did a search of all the articles in this blog and…
What Is a Cold Roof in a Hot Climate?
For those of us who live in warm or hot climates, this question about roof temperature is confusing. A lot of people talk about cold roofs and hot roofs, and unfortunately, it's not just about the time of year, current…
4 Ways to Fix Your Duct System
I've written a lot of articles about ducts here, but I haven't yet addressed today's topic: common problems with ducts and how to fix them. This one is for homeowners or renters who want to save money and be more…
Air Sealing an Attic Access the Right Way
Attic access points can be a mind-blowing thermal liability. If you don't believe me, open the pulldown stairs or scuttle hole and go into an attic on a cold day. Then turn around and look down through the hole. You'll…
Frost in the Attic Has an Obvious Cause
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…
The 3 Safest Ways to Insulate the Top of the House
I recently finished writing the chapter on the interaction of structure and control layers in my book. The last part was on the various ways to insulate the top of a house. The most common, of course, is to have…
How to Insulate a Short Attic Kneewall
Back in my home performance contracting days (2004 to 2007), I spent a lot of time in unconditioned attics and crawl spaces. First, I was there to find problems. Then, if the homeowners hired me, I'd go in and do…
Is It Ever Helpful to Use a Powered Attic Ventilator?
It's time to revisit one of my favorite topics: the powered attic ventilator. Ten years ago I wrote an article titled Don’t Let Your Attic Suck - Powered Attic Ventilators Are a Bad Idea. It's got 169 comments and would…