Q&A | Heat pumps and how they work, explained by a sustainability expert
Carl Duivenvoorden says 50 per cent of homes in N.B. now equipped with a heat pump
As the cost of living continues to rise, people are looking for ways to reduce their consumption of gas and electricity — especially in the midst of some especially frigid weather.
The New Brunswick government has introduced rebate programs to help homeowners afford upgrades that make their homes more eco-friendly and less costly to heat.
About 50 per cent of homes in the province are already equipped with a heat pump, according to speaker, writer and sustainability consultant Carl Duivenvoorden.
Duivenvoorden, who claims heat pumps are the "king" of all heat alternatives, recently spoke with CBC Radio's Information Morning Fredericton. This conversation has been edited for length and clarity.
Q: How do heat pumps actually work?
A. Heat pumps are wonderful devices that are taking the world by storm. They offer tremendous opportunities for us to reduce our energy costs and to lower our emissions.
If you can imagine, a heat pump is basically a device that extracts heat from outside and brings it inside. And, maybe a good analogy would be — it's like a refrigerator turned inside out.
We already have heat pumps in our homes in the forms of air conditioners, freezers and fridges. If you think about your refrigerator, the fridge works to keep the inside cold and then somewhere on the outside, whether on the back or the bottom, that heat is expelled.
Well, that's the heat that the compressor in the fridge got from inside the fridge and it's releasing it out into your kitchen. Now imagine a refrigerator inside out. And it's not a refrigerator, it's your home. So now all of a sudden there's a portion outside that is taking heat out of the outside air. It sounds counterintuitive, but it can even do it when it's cold outside, like a January day.
Q: How is that possible… Where is that heat to pull?
A: It is really counterintuitive, but heat pumps would basically take outside air that might be, let's say –5, and they suck that air in. They take the heat out of it, and they might blow it out and then it's –15.
So they actually wrung a bit of heat out of that outside air, even though it doesn't feel warm to us, and then they bring that heat inside again, the inside-out refrigerator. They expel the heat indoors.
Q: What are the different types of heat pumps that you can get?
A: There's three different kinds. The original heat pump, I suppose, would be geothermal heat pumps.They have a coil or a well… and they get heat from underground. They're great for comfort, they're reliable and they're super efficient all-year-long. They tend to be really expensive to install, something that you'd only install when you're building new because they're really tough as a retrofit.
Second would be air source heat pumps that are for your whole home. You would have a system of ducts through your home and you have a unit outside in the yard — these big boxes sitting in the yard with fans on them spinning — and then a unit inside the house that takes the heat brought in from outside and it blows through ductwork through the entire house. They're quite common, too. Super efficient, but tough to retrofit into a home, so best installed when you're building new.
The third kind is really taking the world by storm. They are called ductless air source heat pumps or mini-splits… and they will have a small outdoor unit, often on a little stand or pedestal, and then a wall-mounted indoor unit that doesn't have any ductwork. It just blows heat right into the space where it is.
All heat pumps are super-efficient. If you imagine, historically, a lot of New Brunswick has been heated with electric baseboard heaters. They would use one unit of electricity to produce 1 unit of heat, right? But the efficiency of heat pumps means that they can use one unit of electricity and produce as much as three or four units of heat.
Do the math on that and you can see what that could do to your heating bill.
One thing to remember — usually when you're installing heat pumps as a retrofit in your home, you've already got a heating system. It's probably a good idea to leave it there. So you've always got that in the unlikely or rare event that it gets really, really cold and it's getting beyond the limit of your heat pump.
Q: When you're thinking as a homeowner about what kinds of systems to bring in, if you're not building new, should you just lean toward a mini-split?
A: I would say for most of us, that's probably true. Because mini-splits are such an easy retrofit in most homes. I remember when they were installed at my mom's place, it was a one-day installation for two heat pumps. I'm guessing that's still the case now.
And, typically they're inexpensive and you can get advice on sizing and location from an energy auditor if you're going through one of the programs or also from your installer who would know their stuff. It's good to do that versus, let's say, going online and buying a heat pump... because it's important to size your heat pumps in accordance with your heating loads.
Q: How can homeowners get help paying for a heat pump?
A: There are excellent programs here in New Brunswick. I recently saw a report card that suggested New Brunswick is one of the best provinces in the country in terms of energy efficiency programs.
Now over half of New Brunswick homes have heat pumps in them — mostly mini-splits — and so to your point, there are excellent programs out there from the province under the banner called Save Energy N.B. There is a program called the total home energy savings program that offers rebates for all kinds of upgrades that you might make to your home. For a mini-split, you can get $400. There's a stepped-up scale where you might get more depending on what type of system you put in. For central ducted systems $1,500, for geothermal $2,000. But, the big thing is first call or register online and get yourself into the program.
It starts with an energy audit. You get a report and then you implement the upgrades. Keep your receipts and you have about nine months and it's flexible.
Then when you're all finished, you get a second audit that confirms the upgrades. You apply for your rebates and get money back that way. But there's a really good second program that's formerly known colloquially as a low income program. It's been renamed now for any household where the total household income is $70,000 or less — those households qualify for a free energy audit. And then a lot of the suggested upgrades would be free as well. The only downer to that one is, as you can imagine, a lot of interest in that program. So there's quite a waiting list.
There are federal rebates for if you happen to be in a home heated by oil to convert it over to heat pumps.
Outside of this low income program that I mentioned, there is also a federal Greener Homes Loan and it's an excellent program too. It is an interest-free loan for up to $40,000 repayable with no interest over a 10-year period. It's a great program and it dovetails nicely with the provincial program.
Q: So even if you're doing a heat pump, and that's the only job, is it worth it to apply for this loan?
A: It probably is. You want to think a little bit about your circumstances. I mean, $40,000, that's enough to do a ton of upgrades to your home. One nice thing too is, as I've mentioned before, when you've done everything that you can to reduce your energy consumption, then go for something like solar. Solar is eligible under both the provincial program for rebates and also under the federal loan program.
Q: What about putting insulation in your basement, would you be able to do a few different jobs like that under this loan program? Like get them all done?
A: Yes, absolutely. Anything that comes back from your audit as a recommended upgrade — insulate the attic, air seal, insulate the basement, install heat pumps and put on solar panels. Any of those, you can do them and keep your receipts and you can get that interest free loan from the feds.
The beautiful thing, is if you do things that have a really good rate of return, which is the whole idea of making energy upgrades really, the savings will essentially make the payments on that loan. You know once the loan is paid, you still get to keep the savings.
Q: Why, of all the home heating options or home energy options, are heat pumps king?
A: Just because they are so convenient, they give such nice heat, and they're inexpensive. They're so efficient. Remember earlier I mentioned how much heat they give per unit of electricity? Nothing else gives a kind of heat unit return like that.
With files from Information Morning Fredericton
