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 flow
The Ol’ Beer Can Pressure Crunch
Air has weight. Air can move things, like giant wind turbine blades. Air can also crush things. I first got to see the power of air in my introductory physics class in college. The professor, Dr. Jeffrey Trahan, showed the…
Building Science Term of the Week: Flux
At first glance, the word “flux” looks like it may not be appropriate in polite company. In fact, though, it’s a word used in physics all the time. Flux comes from the same Latin root that gives us “flow.” The…
Air Change Rates and IAQ
Let's talk about one of my favorite subjects: air. Because of the global COVID-19 pandemic and the novel coronavirus (SARS-COV-2) that spreads it, the indoor air quality (IAQ) community—researchers, mediators, manufacturers, bloggers, groupies—is having a moment. This must be the…
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…
17 Steps to Better Duct Systems
If a 12 step program is good for helping people deal with addictive behaviors, then a 17 step program ought to be better, right? Or maybe it's just a random number that fits the number of tips that popped into…
Busting a Myth About Low-Static Ducted Mini-Splits
I like mini-split heat pumps, especially of the ducted variety. And because I don't like to pay for a lot of excess power, I prefer to use ducted mini-splits with smaller blower motors operating at a low total external static…
The Best Velocity for Moving Air Through Ducts
The first thing to know about the velocity of air moving through ducts is that the slower you get the air moving, the better it is for air flow. That was the main point of my last article. In fact,…