Why Do Air Conditioning Vents Sweat?
Back in the summer of 2005, I got a call to figure out a moisture problem in a new house. The homeowners took me into the master suite, where the first thing to catch my eye was the towel folded…
The Energy Vanguard Blog
Humidity, Health, and the Sterling Chart
The classic chart demonstrating the importance of keeping to the middle of the relative humidity spectrum has been shown to countless attendees of classes, conference presentations, and webinars on building science, indoor air quality, moisture problems, and health. I can't…
My Duct Systems on Low-Static Mini-Split Air Handlers
I've written about the load calculation and equipment selection process I went through for the new Mitsubishi* ducted mini-split heat pump in my house. Now let's take a look at the design and performance of the duct systems for the…
My Low Pressure-Drop, MERV-13 Filters
Filtration is on the minds of a lot of people lately. Because of the coronavirus pandemic, most of us would prefer not to breathe in air that contains any hint of the SARS-COV-2 virus that's been spreading the illness known…
My Undersized Ducted Mini-Split Heat Pump
Last year my wife and I bought a 1961 ranch-style house, and I've been having a lot of fun fixing it up. I wrote about the problem with the spray foam in the attic not covering the top plates and…
Understanding Filter Ratings: MERV, FPR, and MPR
As much as I've written about filters and filtration in this blog, I have to confess there's one aspect of filter efficiency I've resisted learning about. Every article I've written that mentions filter efficiency talks about only one rating scale: …
Do UV Lamps Really Improve Indoor Air Quality?
I used to be a smart-ass who would say things I thought were clever but really were just annoying. When I learned the basics of quantum physics, for example, I had a clever/annoying answer for anyone who asked me, What's…
A House Needs to Breathe…Or Does It?
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…
Can Your HVAC System Filter Out Coronavirus?
Yesterday I gathered with a few of my friends and colleagues from the building performance community for a virtual happy hour. During our chat, Steve Byers of Energy Logic posed the question: Compared to BC (before coronavirus), how will you…
Can You Use HVAC Filters in Coronavirus Masks?
Back in 2018 I wrote a series of articles on indoor air quality and filtration. One of those articles, The Unintended Consequences of High-MERV Filters, has seen a flurry of activity in the comments over the past three weeks. It all…