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Heat Pump vs furnace in Toronto

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  • Jan 30th, 2022 11:38 pm
[OP]
Sr. Member
Dec 23, 2012
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RICHMOND HILL

Heat Pump vs furnace in Toronto

Hello, the new rebate program has a $5,000 grant for new cold climate air source heat pumps. I currently have an old (27 y/o) ducted AC system that works okay but I was thinking this is a good opportunity for a replacement. However, when I looked at heat pumps in the past you still needed supplementary heat (electric or gas) in the winter. I was wondering if this is still the case, or have new heat pumps evolved to the point where they can handle -20 celcius?
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Deal Addict
Oct 19, 2020
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Yes there are systems that can maintain full capacity down to -20c and below, but efficiency still drops. What they call cold climate. Loaded with proprietary electronics.
Much more airflow is needed to supply the same amount of heat compared to a furnace and ductwork is a limiting factor, can still end up needing supplemental heat.

Go furnace in toronto, electricity is too expensive.
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Jun 16, 2009
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Woodbridge
Short answer - Heat pumps in GTA are not worth for one single reason and that is after sale service. Not only part availability can be a issue, finding an expert will not be easy and cheap in comparison to regular gas technicians.
Mosho1 wrote: Hello, the new rebate program has a $5,000 grant for new cold climate air source heat pumps. I currently have an old (27 y/o) ducted AC system that works okay but I was thinking this is a good opportunity for a replacement. However, when I looked at heat pumps in the past you still needed supplementary heat (electric or gas) in the winter. I was wondering if this is still the case, or have new heat pumps evolved to the point where they can handle -20 celcius?
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Jan 2, 2012
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KINGSTON,ON
My last house in Toronto had an air source heat pump with a supplemental electric furnace. It was 1945 era bungalow, typical of huge swaths of East York, with a double brick wall and 3/4" air gap as the only insulation other than the attic. The heat pump could not keep up with the demand of anything below -10C.
It was probably ten years old when I bought the place, (so early '90's build), but that doesn't mean technology has improved to the point of defeating the laws of thermodynamics. Heat pumps work best in more moderate climates, especially when thermal loss through the building envelope is less rampant.
Sr. Member
Dec 6, 2020
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Mosho1 wrote: Hello, the new rebate program has a $5,000 grant for new cold climate air source heat pumps. I currently have an old (27 y/o) ducted AC system that works okay but I was thinking this is a good opportunity for a replacement. However, when I looked at heat pumps in the past you still needed supplementary heat (electric or gas) in the winter. I was wondering if this is still the case, or have new heat pumps evolved to the point where they can handle -20 celcius?
The answer to all heat pump questions is 'it depends.'

Mitsubishi publishes performance tables for their cold weather heat pumps on their technical resources page. Their 42,000 BTU nominal unit produces 48K BTU/hr at -15, but output drops rapidly to 36.5K BTU/hr at -30.

If you do have a well insulated house (2x6 wood construction, double-glazed low-E windows, etc), consider getting a load calculation done to estimate if a heat pump will work for you without backup heat. If your house is not well insulated then a heat pump will not be viable in Toronto unless you install two heat pumps, or have supplemental heat for very cold days.

Keep in mind that you can replace your AC with a heat pump and keep your existing gas furnace for use in extremely cold weather. If the cost difference between a plain AC unit and a heat pump is not much, it's probably worth your while to get the heat pump. A heat pump will be more cost effective than gas down to at least freezing, and may well earn back the price premium over plain AC on a reasonable timescale.

Finally, be aware that a generator can run a gas furnace but can't run a heat pump. This is a disaster preparedness issue if you don't have an auxiliary heat source that will work during a power failure.
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Oct 19, 2020
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MrFrugal1 wrote: My last house in Toronto had an air source heat pump with a supplemental electric furnace. It was 1945 era bungalow, typical of huge swaths of East York, with a double brick wall and 3/4" air gap as the only insulation other than the attic. The heat pump could not keep up with the demand of anything below -10C.
It was probably ten years old when I bought the place, (so early '90's build), but that doesn't mean technology has improved to the point of defeating the laws of thermodynamics. Heat pumps work best in more moderate climates, especially when thermal loss through the building envelope is less rampant.
With supplemental heat cycling on and off, it should have kept up - installer/contractor error. Unless I misunderstood and you meant it kept up down to -10 without supplemental heat.

Most conventional heatpumps sized for a/c in gta won't keep up without supplemental heat below 0c, or even higher when the house has no insulation.

Cold climate models are is a very different and they do indeed maintain capacity very well by use of specialized compressors which ramp up to compensate. There is plenty of heat in the air even at -20c, it is far from absolute zero.

The efficiency may only be 150% (1.5kwh of heat for every kwh consumed) or so at that kind of outdoor temperature, but still beats the heck out of electric elements.

When natural gas is not available, and the alternatives are high dollar oil, propane and straight electric - it actually makes great sense to get a hp instead of a/c in southern ontario, even if a conventional model is used which needs supplemental heat or fossil fuel furnace to take over entirely.
This is if a/c is being added anyway.

Heatpumps are a very broad category of equipment with different style units available; there are good and bad applications.
As far as I'm concerned, one advantage is that they they weed out mediocre contractors who would have nothing but complaints if they installed them; they can get by dealing with furnaces because a furnace will still supply enough heat if poorly installed, incorrectly sized, and totally out of whack when it comes to setup.

In the OP's case though, it doesn't make sense to get one.
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[OP]
Sr. Member
Dec 23, 2012
506 posts
499 upvotes
RICHMOND HILL
Thanks for the answers!

I actually have an update, I double checked and while the A/C is 27 years old, the furnace (goodman) is only 10 years old. So maybe I can have a new heat pump installed with the old furnace as backup?
Sr. Member
Dec 6, 2020
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Mosho1 wrote: So maybe I can have a new heat pump installed with the old furnace as backup?
A heatpump with gas heat for very cold weather is a really common setup.

Unfortunately, high-end heat pumps that can work at -20 (such as Mitsubishi's Zuba) generally require matching air handlers/furnaces. As far as I'm aware, heatpumps that can be installed alongside a standard furnace can only provide enough heat to be useful in a Toronto climate down to zero degrees. If you go this route, plan on using your heat pump for heat only in late spring and early fall.
Sr. Member
Feb 27, 2007
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middleofnowhere wrote: A heatpump with gas heat for very cold weather is a really common setup.

Unfortunately, high-end heat pumps that can work at -20 (such as Mitsubishi's Zuba) generally require matching air handlers/furnaces. As far as I'm aware, heatpumps that can be installed alongside a standard furnace can only provide enough heat to be useful in a Toronto climate down to zero degrees. If you go this route, plan on using your heat pump for heat only in late spring and early fall.
That's no longer the case; as a example MITS Air makes a cold climate unit that's designed to be used with your existing air handler/furnace. I know of at least one or two in the field I've seen that goes down to around -17 to -20 deg. C in a modern 2500 sq ft. bungalow on the Bruce Peninsula before requiring aux. heat. Mind you it's a 3 ton unit, but with the invertor drive it still runs as you'd except as an ac in the summer.
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Mosho1 wrote: Thanks for the answers!

I actually have an update, I double checked and while the A/C is 27 years old, the furnace (goodman) is only 10 years old. So maybe I can have a new heat pump installed with the old furnace as backup?
To get the rebate, the heatpump would have to be a approved match for the heatpump, and a 10 year old goodman won't be.

I minimum I believe to get a rebate ($4000 for a not cold climate heatpump) is 10HSPF, and won't hit that on paper without matching furnace.

Further, very few cold climate style ($4000 rebate) heatpumps are available to be matched with furnaces.

You can get a basic regular one, not high efficiency or cold climate and run it in the spring and fall, automatically switch to gas with a high end thermostat when it doesn't keep up. BUT - it is cheaper to heat with gas in the gta. New power plants have been gas and the price of electricity in ontario b4 subsidies has more than doubled over the last 10 years.
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Oct 19, 2020
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von Monster wrote: That's no longer the case; as a example MITS Air makes a cold climate unit that's designed to be used with your existing air handler/furnace. I know of at least one or two in the field I've seen that goes down to around -17 to -20 deg. C in a modern 2500 sq ft. bungalow on the Bruce Peninsula before requiring aux. heat. Mind you it's a 3 ton unit, but with the invertor drive it still runs as you'd except as an ac in the summer.
Thanks for this information.

I looked it up and it is controlled with a regular thermostat, no mention in the manual of how it modulates - using algorithm or otherwise. No sequence of operation info.

The spec sheet does not show heating capacity at lower temperatures.

Seems they don't like to publish much info.

Not efficient enough to qualify for rebates.

Bosch has one that maintains capacity better than regular and can be used with a regular thermostat and they published much more info to really get an understanding of how it works.
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Jun 24, 2015
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who actually lives in these houses with heat pumps? every house ive seen is furnace, older homes were radiator
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Sr. Member
Feb 27, 2007
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insertname2020 wrote: Thanks for this information.

I looked it up and it is controlled with a regular thermostat, no mention in the manual of how it modulates - using algorithm or otherwise. No sequence of operation info.

The spec sheet does not show heating capacity at lower temperatures.

Seems they don't like to publish much info.

Not efficient enough to qualify for rebates.

Bosch has one that maintains capacity better than regular and can be used with a regular thermostat and they published much more info to really get an understanding of how it works.
The brochure lists the SEER, COP, and the HSPF5; you can do some math from there if you wanted - but I agree they should have more information on their website. They definitely used to to have a nice chart with cold weather performance on it but the website has been resigned since the last time I was on it. You can also get a bit more information on the unit by looking at the specs with the matching air handler - https://www.mitsair.com/wp-content/uplo ... re-7-1.pdf

The modulation is controlled by the interface box - it's a Midea unit (same as the outdoor unit; and to my eyes it looks identical to the units they sell Carrier) - but I can't seem to Google this morning and am only coming up with the mini-split interface board. It will be a proprietary algorithm based on internal (return air) and external temps with some 'secret sauce'. I'm not aware of any company that discloses how it's algorithm works; in any case using a dumb tsat it runs the pump until it no longer is able to keep up with heating and then swaps to AUX; with a smart tstat you can set lock outs and more directly control whether to use the pump or AUX, you just can't set the heat pump invertor.

Oddly enough they've moved a pile of information into their 'training course' which is weird, but I'm guessing a lot of these are installed by people without a large amount of heat pump / dual fuel experience.

Also the rebates are only eligible if it's on the Greener Home rebate list - these Mits Air units are not, but very similar model Midea units are so an email will likely lead you to the eligible Midea unit; on the flip side both units I've seen installed were more than the rebate less than the Carrier/Trane/Lennox equivalents.
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Feb 27, 2007
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GoodFellaz wrote: who actually lives in these houses with heat pumps? every house ive seen is furnace, older homes were radiator
insert :not sure if serious: meme picture I guess?

Pretty much anyone without access to natural gas is much better off with either a full geo or air-air heat pump.
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Oct 19, 2020
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von Monster wrote: The brochure lists the SEER, COP, and the HSPF5; you can do some math from there if you wanted - but I agree they should have more information on their website. They definitely used to to have a nice chart with cold weather performance on it but the website has been resigned since the last time I was on it. You can also get a bit more information on the unit by looking at the specs with the matching air handler - https://www.mitsair.com/wp-content/uplo ... re-7-1.pdf

The modulation is controlled by the interface box - it's a Midea unit (same as the outdoor unit; and to my eyes it looks identical to the units they sell Carrier) - but I can't seem to Google this morning and am only coming up with the mini-split interface board. It will be a proprietary algorithm based on internal (return air) and external temps with some 'secret sauce'. I'm not aware of any company that discloses how it's algorithm works; in any case using a dumb tsat it runs the pump until it no longer is able to keep up with heating and then swaps to AUX; with a smart tstat you can set lock outs and more directly control whether to use the pump or AUX, you just can't set the heat pump invertor.

Oddly enough they've moved a pile of information into their 'training course' which is weird, but I'm guessing a lot of these are installed by people without a large amount of heat pump / dual fuel experience.

Also the rebates are only eligible if it's on the Greener Home rebate list - these Mits Air units are not, but very similar model Midea units are so an email will likely lead you to the eligible Midea unit; on the flip side both units I've seen installed were more than the rebate less than the Carrier/Trane/Lennox equivalents.
The bosh modulates to maintain consistent head pressure in heating mode and suction in cooling mode.
For that one, can stage the indoor fan and the outdoor unit follows, and also has compensation for cold weather.
Could be similar.

I'm leery of companies that don't share much information.
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Feb 8, 2014
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A lot of replies are actually about not liking heat pumps on principle. Many work well down to -30C. But you have to buy the right model.

That said get many quotes and ask questions, how are parts availability, what are the most common repairs, what is the efficiency at different temperatures and so forth.

If you can pair it with your existing furnace that is a huge bonus and gives you excellent flexibility.
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Dec 6, 2020
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GoodFellaz wrote: who actually lives in these houses with heat pumps?
I have one. They're pretty common here on the west coast.
Newbie
Oct 23, 2009
2 posts
Hi everyone.

I’m in East York and building new home and really are debating between a gas furnace + AC VS Hear pump.

We are planning to put 2 system to heat
-upstairs
-main + basement.

The all house will be isolated by foam.

Thank you for your options and suggestions.

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