How To Electrify A Home In Any Climate
Every day we hear more about the idea of “electrifying everything” as one of the clearest paths to eliminating our carbon emissions. Combine clean renewable power with efficient all electric appliances and you have a recipe for a carbon neutral, comfortable home. But what about those of us living in the northeast and midwest? Is it really possible to electrify a home in any climate, even cold ones?
To answer this big question, I talked with one of the patron saints of electrification, Nate Adams, otherwise known as Nate the House Whisperer. Nate is based in Cleveland, Ohio and knows both snow and old houses and is an evangelist for smart electrification, or as he calls it, “HVAC 2.0.”
Nate thinks that electrifying homes in cold climates is both doable and necessary, but that it can and should take thinking and planning. “Doing electrification projects is not unlike getting married,” he said. “You don’t walk into a bar and ask someone to marry you. You know that’s just not how it works, electrification is more of a relationship building exercise.”
Insulate & Test Your House
With homes in colder climates, Nate finds that insulation and air sealing are key to enabling electrification. “The basics of it are pretty simple. you just have to get a house tight enough so that a heat pump will carry the heating.” How do you know if your house is tight enough? You need a blower door test, which measures how leaky the house is. Once insulation levels are above a minimal level, air leakage is usually the biggest factor in how much it takes to heat a home.
“Doing a heat load calculation will figure out how much it takes to heat a house on the coldest days of the year.” A heat load calculation is where you calculate how much heating and cooling your home will need and put in factors like how big your home is and how much insulation you have. They really only become accurate if they are “trued” to both a blower door leakage test as well as energy use, otherwise they can easily be off by +/- 50%, leading to selecting the wrong HVAC. Doing load calculations with both blower door and energy use is part of an HVAC 2.0 Comfort Consult, which makes it very electrification friendly.
Nate has found that approximately half of homes in colder climates he’s worked with will be immediately ready for electrification, and the other half will need some air sealing and insulation work. The problem with insulating an older house is that unfortunately, you might not get a full financial return on that investment for a while (if ever).
“The critical thing that isn’t talked about enough is if you do a substantial shell retrofit you’re very likely to get nothing for that when you sell the house. That’s burning wealth and that’s a bad thing. It’s not scalable. As much as possible when we spend money we want to do it in a way that lets it be recycled and come back to us.”
Insulating a house will lower utility bills and increase a family’s comfort level dramatically, but Nate’s point is that it should actually increase the value of the home as well, and if it did, it would make insulating homes more common and the expense more justifiable. He pointed to a couple of cities (Washington D.C. and Chicago) that disclose a home’s energy use to a buyer, which adds value to homes that are better insulated. Regardless of return on investment, a reasonably tight home is essential to go all electric in cold climates.
Heat Pumps Work Almost Anywhere
Image courtesy of Electrify Now
If step one toward the all-electric home in cold climates is to check out your home’s shell (where inside meets outside) and insulate as necessary, step two is to figure out what heating and cooling system to put in. The good news is that heat pumps will work pretty much anywhere.
“Heat pumps used to really only be good down to about freezing,” Nate said, “now they’re good to about minus 20.” Nate is confident that regular heat pumps work in climate zones 1-4 (see map below) and that the cold weather heat pumps work in all of climate zone five. According to Rocky Mountain Institute – “Leading products are now capable of performing well below -10°F and operating at more than double the efficiency of electric resistance or gas systems below zero.”
So that means most of the United States, which is located in zones 1-5, could heat their homes using heat pumps and still do so really efficiently. What about zones 6 and 7? According to Nate, “to do all-electric in climate zone six and run heat pump only, you’ve got to have your house pretty tight and use a top of the line heat pump, but a hybrid heat pump plus furnace will work all year long.” In the small areas of climate zone 7, you may need a hybrid heat pump gas/system.
Image courtesy of PNNL
Hybrid Heat Pump + Gas
Another option for heating in really cold climates is to buy a hybrid heat pump + gas furnace. Think of a heat pump like a 2-way air conditioner, as it can heat as well as cool. They are the same piece of equipment as an air conditioner, and they just have a few extra parts so they can run in reverse. Most ACs have a heat pump version and the wholesale cost difference is $300-600.
These “dual fuel furnaces” have a heat pump that sits directly on top of a gas furnace and provides all the heating and cooling a house needs down to a certain temperature that the owner sets (typically 5-45 degrees Fahrenheit). Then, when the temperature drops below this mark and the heat pump can no longer carry the heat load, the natural gas kicks in. Depending on the temperature you set, you could end up using fossil gas as a backup only on the coldest days of the year.
Hybrid or Dual Fuel Heat Pump + Gas furnace – Image courtesy of Rheem
Nate has studied several projects in Cleveland and found that if you use a gas/heat pump furnace and set your heat pump to provide all the heating until it gets below 25 or 30 degrees Fahrenheit, it will reduce your gas usage by about 90%. Reductions of 40-90% are common in climate zones 5-7, and zones 1-4 often see 100% reductions using hybrids. The likely outcome of that, according to Nate, “is that’s going to kill the gas utilities. Because they’ve got all this pipeline and distribution to support and then we’re going to cut their sales by 90%. This is going to make their meter fees go up and very quickly having a gas furnace is going to be more expensive than having a heat pump.”
While heat pumps alone work for most of the country, hybrid heat pump + gas furnaces are an important transitional tool for homes in the colder climates (zones 5 – 7), allowing homeowners to get nearly full electrification for less cost and do so immediately.
Nate is currently pushing to get a law passed where all gas furnaces have to come with heat pumps instead of air conditioners so that everyone gets to experience the comfort and efficiency of a heat pump for heating and cooling, and we begin to electrify on a massive scale.
Selling People On Comfort
Heat pumps are more efficient than other forms of heating, but due to rock bottom natural gas prices they may not save people lots of money. So finances aren’t a big selling point. Nate also worries about people pushing electrification for environmental reasons in the heartland of the US. He says that argument works for “a handful of wealthy liberals,” but won’t move the needle on mass adoption.
The way to sell heat pumps to homeowners and contractors, according to Nate, is “comfort.” He thinks that those of us pushing electrification should be focusing on the message that “electrification makes people happy.” Heat pumps and the insulation required to make them work well, provide a comfortable source of heating and cooling that avoid the blasting, dry air of a gas furnace and the cold air coming in from a leaky house.
Whatever the selling point, after talking with Nate, it’s apparent that heat pumps are the clean heating/cooling systems of the future and that with a little preparation they will make people more comfortable anywhere, even in the coldest climates.
If you would like to take a deep dive into home electrification, Nate created a free Electrify Everything Course that will bring you up to speed on both the ways to talk about electrification to your mainstream friends and on all the nuts and bolts you need to know about electrifying your home. It’s a dozen emails and videos over several weeks.
I’ll be hosting a webinar on ductless heat pumps with the all-volunteer non profit Electrify Now on July 14. Ductless heat pumps are key to electrifying in any climate. Register here for the webinar.
