An Air Conditioner Does at Least 4 Jobs
The most noticeable thing about an air conditioner is that it blows cool air into the house. When you come indoors after doing yard work on a hot summer day, that may be all that matters to you. But air…
dehumidification
Building Science News & Trends for 2025
Several years ago, I heard something really interesting at a talk by a self-described futurist. It's an interesting "Futurists," she said, "look at weak signals and try to figure out which ones will become strong signals." I hadn't thought…
10 Ways to Reduce Your Indoor Humidity
With our changing climate, more people are having to deal with higher humidity for longer periods of time this summer. I'd say this has been probably the worst summer for humidity since I moved to Georgia in the summer of…
Hotels Have a Humidity Problem
If you travel with a hygrometer, as any seasoned traveler should, what I have to show you here is nothing new. But if instead you've never measured the relative humidity in a hotel room, I've got something interesting for you…
5 Tips for Sizing an Air Conditioner
So you're getting a new air conditioner! Well, what size should you get? Unfortunately, too many contractors use only one input for sizing an air conditioner. Yup. To them, it's just a matter of floor area. Forget the windows, the…
4 Ways to Duct a Dehumidifier
Humidity control is becoming a bigger deal than it used to be. As Joseph Lstiburek, PhD, PE said to me one time, "the gap between stupid and hurt is narrowing." Building codes and best practices are getting better, which is…
Living With a Heat Pump Water Heater
It was two years ago this week we had the nasty old fossil gas natural draft water heater removed. (That's it in the photo below.) Outside of running a gasoline powered generator inside a house, this kind of water heater…
Measuring the Efficiency of a Room Dehumidifier
A few months ago, I wrote about the confusing world of dehumidifier capacity. That quantity tells you how much water a dehumidifier will produce in a given amount of time. Here in the US, we use pints per day, but…
Building Science Term of the Week: Grains of Water
Every area of building science has its jargon. And I'm not just talking about the acronyms, initials, and abbreviations that get thrown around casually. I've been making a list of the most interesting, useful, or stupefying BS terms and giving…
The Confusing World of Dehumidifier Capacity
Dehumidifiers have one job: to turn water vapor into liquid water by moving air over a cold coil that's below the dew point. The capacity, or size, of a dehumidifier is just the rate at which it does that conversion. …