Are You Making This Mistake with Humidity?
I want you to think about humidity today. Look at the photo above. What do you see? Dew drops on blades of grass. Where did that water come from? Out of the air. What was it about the air that…
moisture problems
The Pen Test — A Control Layers Tool for Architects and Contractors
I listened to the IAQ Radio podcast a couple of weeks ago when they interviewed Lew Harriman and Terry Brennan, who were discussing the new moisture control guide published by the EPA last year. Brennan is the lead author of…
A Line in the Sand — The Dew Point Duct Duel
A line in the sand has some significance for Texas, the state where I was born. Colonel William Travis used his sword to draw such a line in the waning days of the Battle of the Alamo. As General Santa Anna…
The Great Ventilation Debate – Live at Affordable Comfort!
Last week at the Affordable Comfort Conference (also known as ACI), I co-moderated a panel called The Great Ventilation Standard Debate.1 Duncan Prahl of Ibacos proposed the session and rounded up a collection of some of best building science folks…
What Happens When You Put a Plastic Vapor Barrier in Your Wall?
A lot of people have heard advice about vapor barriers and vapor retarders. Many of them have walked away confused. A big part of the problem, I think, is that they've been told what to do—"Put it on the warm-in-winter…
Solving a Crawl Space Water Mystery
When I started Energy Vanguard in 2008, I didn't know how it would evolve and had thought early on that I may get back into home performance contracting. I did a couple of jobs, the last one being a crawl…
![Dead Possum Lying Next To A Disconnected Return Duct In A Nasty Crawl Space [Photo Courtesy Of E3 Innovate]](https://www.energyvanguard.com/wp-content/uploads/2020/05/crawl-space-return-duct-dead-possum-e3-innovate-900-annotated.jpg)
4 Ways a Bad Duct System Can Lead to Poor Indoor Air Quality
Indoor air quality (IAQ) is a big deal. It doesn't get near as much attention as energy efficiency or green building programs, but it should be one of the highest priorities for anyone who lives in a home. It's actually…
Frost on Indoor Walls – A Dramatic Insulation Failure
Not long ago, Erik Henson an energy auditor with HD Engineering and Design in the Kansas City area, posted the photo below on LinkedIn. As you can see, frost has formed on the walls and ceiling inside the house. It's…
Air Barriers, Vapor Barriers, and Drainage Planes Do Different Jobs
Is housewrap a vapor barrier? What's the purpose of building paper? Who'll stop the rain? I've covered this topic in various forms before, but the confusion about what the different building materials do is so widespread that I have to…
6 Materials That Drain the Rain on the Plane and Keep A House Dry
Are you ready to take the next step in being a building enclosure control freak? You already know about the 4 types of control layers, so let's go further now and look at the one that controls liquid water. But…