Are you confused? In my last article, I said buried ducts are at risk for condensation. Now I'm telling you they'll be allowed in the 2018 code. What's going on here? The answer is simple. Yes, when you bury ducts…
Water vapor from the air condenses on air conditioning ducts in humid climates. It's as normal as poorly insulated bonus rooms making occupants uncomfortable or cigarettes causing lung cancer†. Condensation on ducts is most common in crawl spaces and basements,…
"You know where this is going, right? Codes will eventually require balanced ventilation." I've heard people say this more than once in the past year or so. As someone who has been attending the semiannual meeting of the ASHRAE 62.2…
Some people love flex duct. Some people hate it. Some of us are OK with it if it's done right. As I've documented here numerous times, many flex duct installations leave a lot to be desired. They sag. They're kinked.…
If you want to build a superinsulated, airtight house, you run into some difficulties. How do you deal with the extra thickness of your walls and ceilings when you add all that extra insulation? What's the best way to ensure…
Everyone knows about the impact of burning fossil fuels on global warming. Maybe not everyone believes it, but scientists first started focusing attention on increasing carbon dioxide levels way back in 1827. The impact of insulation on global warming, however,…
At the North American Passive House Conference in Philadelphia in September, I gave a presentation on the global warming impact of insulation, an issue I've been discussing off and on since Alex Wilson wrote his paper on the topic back…
It's that time of year when heating systems start coming out of their summer hibernation. (Except maybe in Vermont. Michael Blasnik's Nest data showed that Vermonters are about the last to start heating their homes in Fall.) Then everyone starts…
Supply and demand are two different things. When you think of an energy code, say the International Energy Conservation Code (IECC), you probably think of demand, not supply. Conserving energy, after all, means reducing demand. It's related to supply only…
You can go into just about any introductory physics classroom and you'll see that the students learn the same stuff no matter which school they attend. They study forces and motion, momentum and energy, electrostatics, and a host of other…