It's time to revisit one of my favorite topics: air conditioner sizing. Many contractors use rules of thumb to decide what size cooling equipment to install. Usually, the rule is based on the amount of conditioned floor area, and contractors…
The humidity is returning for the summer here in the southeastern US. And as you may know, I don't use relative humidity to gauge how humid the outdoor air is. Why? For starters, the humidity can get up to 100%…
Gary Klein, a guru of efficient hot water delivery, has been pushing for change in hot water distribution systems for a long time. In recent years, he and his colleagues have developed a great tool for quantifying the efficiency of…
Heat pumps are riding a wave of demand and curiosity lately. With all the talk of electrification and decarbonization, heat pumps are in! We specify heat pumps in most of our HVAC design jobs at Energy Vanguard. We've got them…
When can doing something good for your house turn into something bad? Hmmm. There are way too many answers to that question, so let me narrow it down. Is it possible to make your ducts more airtight, a good thing,…
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…
Sometimes a house just needs a lot more air conditioning than building officials want you to put in, right?* It's better to be safe than sorry, so having extra heating or cooling capacity can be a good thing. Today I'm…
Oh, the controversies of duct design. Standard versus high-efficiency filters. Radial versus trunk and branch. Central versus dedicated return vents. Flex versus sheet metal ducts. But there's another duct debate that centers around the location of the filter. In our…
The quote below is a classic from the 1893 book, Ventilation and Heating, by John Shaw Billings. The imagery of wearing someone else's dirty underwear may shock you, but Billings makes a compelling point. We essentially do something worse whenever…
I taught Manuel about sealing the holes in air barriers, ducts, and crawl spaces. He taught me how to face my fears by sticking my arm into holes in the ground. Manuel was my best worker when I did home…