Understanding Manual J Occupant Loads
People complicate things. If, say, you want to sell a motorcycle, you place an ad and interested potential buyers come check it out, maybe take it for a little ride, and then one of them buys it. But every once…
heating & cooling
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…
My New Project: A 1961 House With Home-Performance Angst
Let me tell you the story about a poor, young country boy who broke the law and launched me into my new project. Back in February, I was driving home from work one evening when a driver T-boned me. The…
Two Ways to Change the Heat Pump Balance Point
So we've looked at a simple way to estimate the heat pump balance point. If you also read the comments of that article, you should be aware that there's more to the actual balance point than what I wrote in…
A Simple Way to Calculate Heat Pump Balance Point
As the outdoor temperature drops on a cold day, a home's heating load increases. At the same time, decreasing temperature means less heat in the air for a heat pump to pump indoors. And at one special temperature, the capacity…
The 3 Types of Heat From Heat Pumps
Since more people are using heat pumps these days, even in cold climates, let's spell out the three different types of heat that conventional heat pumps provide. Why not! We've just recently covered the three main sources of home heating…
3 Sources of Heat for High-Performance Homes
Earlier this week I wrote about the three main sources of heat in homes. At the end of the article I threw in a fourth one, solar energy, but then I dismissed it as something that people tried in the…
The 3 Main Sources of Home Heating
It's wintertime in the Northern hemisphere and that means we're heating our homes. The new year started off a bit on the warm side, with the temperature at nearly 70° F (21° C) here in the Atlanta area. In terms…
Does Fiberglass Attic Insulation Really Lose R-Value?
When you get into the world of building science, it's inevitable that you'll hear about the study that proved fiberglass insulation loses half its R-value because of convection within the insulation. Or it could be you're a homeowner who's been…
The Unintended Consequences of High-MERV Filters
What is a hair's breadth? A strand of the finest human hair is about 20 micrometers (also called microns) in diameter. Take a piece and slice it in half. Then take one of those halves and slice it in half…