Ductless Mini-Splits Can Get Nasty Inside
Have you ever used a flashlight to look up into the part of a ductless mini-split where the air blows out? I should have done that a lot sooner than I did. It turns out these heat pumps can get…
heating & cooling
To Zone or Not to Zone…and How?
Unless you have a simple, small home, you probably want more than one thermostat to control the heating and cooling. That lets you control the conditions separately in different areas. And that's where zoning comes in. A common example is…
Will a Heat Pump Work With Your Existing Ducts?
OK, you're thinking of replacing that old furnace in your home with a new heat pump. But you have doubts. You've heard that heat pumps don't heat as well as furnaces. (Wrong.) Or that they'll jack up your electricity bills…
Going Deeper With Control Layers
Controlling the flows of heat, air, and moisture is where building science begins. This is so important that I devoted more than a third of my book to the building enclosure and control layers. As much as I love discussing…
The Achilles’ Heel of Heat Pumps
Air source heat pumps are a great way to keep a home comfortable. On the cooling side, they're exactly the same as an air conditioner. In heating mode, though, they have a limitation that other types of heating equipment don't…
What’s the Correct Air Flow for an Air Conditioner?
Air conditioning is a wonderful thing. Now that warm weather is returning here in the northern hemisphere, ACs are getting turned on and cranked up again. The air in a house gets warm because of the heat coming in through…
What Happens to the Frost on My Heat Pump?
This is the fifth winter since I've been heating my house with a Mitsubishi* heat pump. And finally I got to see something I've missed every time it happened until last week. Yep. I'm talking about seeing frost on the…
Fireplace Building Science – Pros and Cons
Ah, who can resist the ambiance of a crackling fire! Well, it turns out quite a few can. Whether to use a fireplace or not is a controversial topic in building science. The main problem is that a typical wood-burning…
How a Heat Pump Gets Heat From Cold Air, Part 2
Everyone's talking about heat pumps. These machines for heating buildings can exchange heat with the outdoors in multiple ways, of course. Ground-coupled heat pumps pull heat out of the ground or water and send it to heat the building. But…
Heat Pump Basics
Whether you're thinking of getting a heat pump or you already have one, knowing these heat pump basics can help you get the right heat pump and operate it properly. The Inflation Reduction Act (IRA) here in the US has…