Cold Climate Heat Pumps (Podcast)

7 months ago

In this podcast, we look at cold climate heat pumps. The owner of Cape Cod Heat Pumps, Jared Grier outlines the benefits of cold climate heat pumps and explains how they work. Learn why their variable compressors help improve efficiency, while also enhancing the comfort of your home.

Cape Cod Heat Pumps · Cold Climate Heat Pumps

John Maher: Hi, I am John Maher. I’m here today with Jared Grier, owner of Cape Cod Heat Pumps, an HVAC contractor in Marstons Mills, Massachusetts on Cape Cod, specializing in ductless heating and cooling technology and focused on detail, quality and professionalism. Today our topic is cold climate heat pumps. Welcome, Jared.

Jared Grier: Hi, John. Thanks for having me.

What Is a Cold Climate Heat Pump?

John: Sure. So Jared, what is a cold climate heat pump and how does it differ from a traditional heat pump?

Jared: That’s a great question, and quite frankly, I get that all the time. Back in the 1980s when we had the oil embargo, electric heat and heat pumps were all the rave. But the heat pumps we have today are nothing like what we had 40 years ago.

Those heat pumps, the more traditional style heat pumps, once we get below freezing, they really start to drop off in their capacity. Cold climate heat pumps, rather, we have full capacity. The LG RED product that we use, Mitsubishi Hyper Heat, those products, they have full capacity at five degrees and will continue to operate down to negative 13.

So being here on Cape Cod, where the average winter day is about 40 degrees, my system’s going to perform perfectly and work great in this climate here. And we’re able to do that with the technology that’s built in this equipment. It uses what’s called the variable speed compressor. So we can spin that compressor really slowly to give you just a little bit of heat to maintain your temperature, and then we could spin that compressor really quickly.

So that’s allowing us to remove or absorb that heat at those very low temperatures outside, although (and I get this question a lot) it’s cold outside. Well, yeah, we’re human beings. We’re trying to keep a 98 degree core body temperature. But refrigerant, there’s still heat in the air and there’s still heat that it can absorb and transfer into the house, and it can do that very effectively at low temperatures.

Misconceptions About Heat Pumps

John: Okay. So for homeowners that might still harbor some doubts about heat pumps handling these cold New England temperatures, can you debunk some of the common myths and misconceptions about cold climate heat pumps and explain how they’ve evolved over the years?

Jared: Yeah, the first thing I’d say is if these didn’t work, I wouldn’t be owning a business right now because this is our primary work. The other thing I’d mention is last year in 2023, we had some unprecedented weather come February last year where it was about negative 15 degrees for almost an entire weekend. That weekend, we only had three service calls, and I will tell you, not one single one of those customers was a heat pump customer.

So these systems, they do work, they work very well. The one thing we do tell people when we get into those really cold temperatures is just make sure you leave the system on and maintain a temperature. It might have a hard time recovering, but it’ll absolutely heat your home. So these systems, they do work, they work very well, even at very low temperatures.

John: So it might have a harder time, say, if the heat went out for a few hours or a day or something like that, and your house got really freezing, and it was still minus 15 degrees outside, it might have a hard time heating the whole home from a cold state. But maintaining the temperature that it already has in the house, that’s not as hard for it, and it would do that very well.

Jared: Yeah. When we go out to a home and we’re designing a system, we’re doing a Manual J, that’s a heat gain, heat loss calculation. So we’re going to basically say, on the hottest day that we might expect, what are we going to need to cool your home? And on the coldest day of the year, what are we going to need to heat your home?

The smallest furnace that I can buy, a conventional style furnace, is 40,000 BTUs. The largest LG RED heat pump that’ll operate down to negative 13 outside I can buy is 48,000 BTUs. So you can imagine with a home that maybe we’re pulling out a 100,000 BTU furnace, which is oversized, because we’re going to do that low calculation, we’re putting in a 48,000 BTU, which is going to be much more appropriate and more efficient for the home.

But yes, it’s going to mean that that recovery might take some time. It was similar to when high efficiency boilers first came out that modulated their temperature. So we’ve just gotta have that same mentality when it comes to these heat pumps and cold, cold weather.

Winter Temperatures in Massachusetts

John: Another thing to consider too is that, as you mentioned last year, we had those couple of days where it went down to minus 15, but that doesn’t happen very often. We go years before something like that happens where we get that cold, and then actually the number of hours that we average below even 20 degrees or 10 degrees here in Massachusetts is actually very low.

We think of these winters in New England as being pretty harsh, but in reality, if you look at the number of hours that it actually is very, very cold, it’s not that many, right?

Jared: No, it’s not. As I said, the average winter day around here is 40 degrees or warmer. The other thing I’d mention on that whole point is, one of the largest markets in recent years for heat pump systems has been Maine. And Maine gets cold. So now the big push for them up in Maine is because they’re so remote out there, everybody’s got electricity for the most part, but you might have oil, propane, coal heat, wood, things like that.

So there’s a big push up there to get rid of those fossil fuel systems and put in clean electric heat pump systems. And quite frankly, if it could work in Maine, it could work on Cape Cod.

Efficiency of Cold Climate Heat Pumps

John: Absolutely. So how efficient are cold climate heat pumps in the extreme cold, and where does that efficiency drop off below a certain temperature? I think you mentioned that you get that 100% of the efficiency down to, what was it, five degrees? And then below that you start to lose a little bit of efficiency?

Jared: Yeah, so there’s a couple of things we’ve got to kind of un-pack here. There’s a difference between efficiency and capacity.

John: Okay.

Jared: We just talked earlier about a 40,000 BTU furnace. So a 40,000 BTU furnace could provide you 40,000 BTUs while it’s 50 degrees outside or it’s five degrees outside. It’s a 40,000 BTU furnace. Because of how heat pumps work, instead of creating heat, they’re moving heat. As it gets colder outside, there’s going to be less heat available so their capacity does go down as the colder it gets. But as you just alluded to, LG RED systems, they have 100% capacity at five degrees, which is well below our normal temperatures here on Cape.

John: Mm-hmm.

Jared: When it comes to efficiency, heat pumps are rated on a COP. I think that’s the most ideal way to read these systems. So coefficient of performance. Above 40 degrees, our COPs are over four. So that means for every kilowatt of electricity that we’re using, we’re creating four times the amount of heat that that electricity that we’re using would produce.

So when we get into the colder temperatures, those COPSs will get down to two. But as you alluded to, we’re not at those temperatures very often, and it might just be for a few hours overnight, but then by the time that it gets warm outside the next morning, we’re going to be nice and efficient in heating the home.

Features and Functions of Cold Climate Heat Pumps

John: Okay. Can you talk about some of the additional features and functionalities that cold climate heat pumps have to enhance comfort, such as smart controls, dehumidification options, and other features that might enhance winter comfort and energy savings?

Jared: Yeah, one huge inherent benefit and feature that you get with a lot of these systems is a lot of zones. There are a lot of common installations too. We’re doing wall units, floor mount units, things like that. And each one of those individual indoor units is its own zone. It can act independently of the rest of the system.

So what’s really nice is if you’re just in the bedroom at night watching TV, you can make it a little bit warmer there and leave the rest of the house a little bit cooler. So that’s a really nice feature for some energy savings and just overall comfort as well. A lot of these systems, they’ve got smart features that allow you app control from remote and us being here on Cape Cod and a lot of these homes being second homes, that’s a real nice feature for people to be able to just check on their home, but also be able to maybe turn the system up before they get here.

One beauty of these systems is that inverter compressor, that inverter compressor that instead of giving you everything it’s got and shutting down is going to try to find that sweet spot. The analogy I like to make is kind of like the cruise control on your car. When you’re in stop and go traffic, that’s a more traditional system, you’re going to hit the gas pedal, you’re going to heat up the house, then you hit the brake and we’re going to shut down, and then the house has got to cool down. And so you get this sine wave effect of being hot, cold, hot, cold.

The mini split, these variable speed heat pumps, the way they operate, that compressor, as I said, is kind of like cruise control. It’s going to try to just run at the bare minimum to maintain your temperature or if you ever felt the pedal, when you’re on cruise control, you’re just fluttering the gas there ’cause you’re just trying to maintain your speed. And that’s how these work as well.

John: And as we know, you get better gas mileage on the highway when you’re going 55 miles an hour and you’re just keeping the pedal down at a certain level. It’s not all the way to the floor. It’s not braked either. You’re not stopping. That’s why we get better gas mileage on the highway than we do driving in the city when we’re constantly stop and go. So it’s like that.

Greater Efficiency, Improved Comfort

Jared: Yeah. And what that’s going to directly translate to your home environment, it’s going to be more comfortable. It’s not going to be hot and then cold and hot and cold as your thermostat is on off on off. The other thing it’s going to be great for is in the summer months when we have those much longer run times on the more mild days, we’re going to do a much better job dehumidifying and drying out your home. So if we’re able to remove that humidity more readily, you could actually turn up the temperature at home and feel just as comfortable because often it’s not the heat that we’re fighting down here, it’s that humidity.

John: Right. So you could leave it, you don’t have to have the temperature at 68 or 70 degrees. 75 in the summer might be totally fine as long as it’s nice and dehumidified in the house.

Jared: Yeah, I’ve been in a ton of homes where you’re walk in and it’s going to feel cold, but it’s also going to be feel cold and clammy. And that’s just because that system is so oversized or just hasn’t had enough runtime that it’s able to wring out that moisture. I personally, I have this technology at my house. I keep my house at 75 degrees in the summertime and everybody kind of looks at me crazy, but it’s so comfortable when you’re able to keep that humidity at a more appropriate level and a more comfortable level.