One of the points of contention in the great ventilation debate is whether a home's occupants should control their own ventilation systems. The issue came up again in my article last week, Does a Gas Furnace Dry Out the Air…
I get asked from time to time if a gas furnace dries out the air in a home and makes a humidifier necessary. I've written about humidifiers and psychrometrics before, but it's still worthwhile making this point explicitly. Even some…
They say you can't fix stupid. They're wrong. When it comes to ice dams, we know how to fix what is the most common cause.† If you know a little building science, you can look at the photo below and…
If you want to do something really stupid with the ducts for a heating and air conditioning system, put them in an unconditioned attic. In cold climates, designers, builders, and contractors know this and, for the most part, avoid it.…
We're a few days into 2014 now. A lot of homes got built last year, and a lot got renovated, too. Quite a few homes got home energy ratings, and even more had blower door tests. Spray foam attics and…
2013 is almost history. Just a few short hours left before the giant possum drops into the bonfire to ring in 2014. (That's the New Year's party I go to each year, and it's always a lot of fun.) So…
I saw the photo below on the Structure Tech Facebook page recently. (They're a home inspection company in Minnesota that appreciates building science.) In this case, everyone can see one of the problems. Even if you know nothing about building…
I've been on the road this week. I flew to Chicago on Tuesday and gave two presentations at the Better Buildings: Better Business conference put on by the Energy Center of Wisconsin. After I was done there on Wednesday, I…
Relative humidity is what everyone likes to talk about. It gets the attention, but it can be confusing, especially when the temperatures drop. The truth is that, despite a high relative humidity, cold air is dry air. For example, at…
A new study from Lawrence Berkeley National Laboratory (LBNL) makes a bold claim that increasing ventilation rates can cut the number of student absences related to illness. The lead author on the paper, Mark Mendell, is quoted by LBNL's News…