Heating and Cooling in Ontario

Brad Barbeau · April 2022

I haven’t posted for years but continue to lurk and enjoy the discussions. Looking for some advice/thoughts about

I am moving to a new house this summer, about twelve years old, well insulated good windows etc. (coming from something 180
years old…).

We are in a location without natural gas and currently the house is heated with two propane furnaces (90%). One furnace is 80k and the other 60k. I have not seen the heat loss that was done when it was built yet but that seems likely to be oversized to me (maybe cut those in half?) - have to do the math on that though. The furnaces are 12 years old and so is the AC.

If you were going to improve operating efficiency or reduce costs, would you do any of the following or even a combination:

1) hydro air with one boiler
2) leave the furnaces for now, cold weather air source heat pump, maybe add solar PV too
3) do nothing at all, replace furnaces for like when they die

Would solar thermal ever be a reasonable addition for to option 1 maybe? Or is that dead as some are saying?

Just starting to think and would like at the very least to be efficient to operate and green.

hot_rod · April 2022

Do everything you affordably can to improve the shell of the home. That is you best return. A load calc, blower door and infrared scan are good starting points.

You have a very strong A2WHP industry in Canada. Products built in, and designed for your climate in Canada. Keep an eye on those. Electricity seems to be the most stable energy cost. LP probably the least stable. In the right application heat, cool and DHW at 2-3 COP.

I don't suppose you can tie into that Enwave DLWC deep lake water cooling district system?

Hot_water_fan · April 2022

If you can get it, ask for historical gas usage. That’ll help with sizing. Or you could wait one winter and know for sure.

Option 1 doesn’t have much merit - the best you could do is match a high efficiency furnace.

Option 2 makes the most sense for potential financial and environmental savings depending on electricity rates. Hybrid setups are common and well understood. You’ll replace the AC one day anyway, so there’s a small upcharge going from AC to heat pump. There’s a chance you won’t need the furnaces ever, but if they’re installed may as well keep them.

Option 3 is expensive but could work, though sizing is probably off. Doesn’t get you AC, so it’s doubling up spending. It’s not green.

Solar PV might make sense independent of heating decision. The benefit of going with a heat pump is that you’d install a larger array, which generally is cheaper. Some areas let you buy clean energy from your utility, so it’s not required to install the panels yourself.

Switching to electricity will be the greenest option most likely (depends on the grid). It may or may not be the cheapest, depends on rate structure.

Solar thermal is a lot of hassle for little gain. Electricity is more valuable than warm water.

Hot_water_fan · April 2022

Air-to-water heat pump plus hydro air would be another great option, @hot_rod is right

Brad Barbeau · April 2022

Thanks for those thoughts!

Hot rod - no, no lake close by unfortunately. Could potentially do wells but would need to run the numbers on that and make sure there is space too.

hot_water_fan - Quite right, I should have said I was intending to verify and improve the envelope first. I’ve got access to a blower door kit through a friend so that gives me some freedom to do that carefully.

I think it might be the case that we could run 98% of the winter without ever needing the furnaces. It is rare that it gets below -5f here, around 5f would be low.

My only thinking with hydro air was that one modulating appliance might be more efficient than two oversized but electric costs are way more stable. I do have their costs for the previous winter and could reverse engineer that to get an approximate usage (we have the same supplier and rate).

Hot_water_fan · April 2022

My only thinking with hydro air was that one modulating appliance might be more efficient than two oversized but electric costs are way more stable.

Air-to-water would allow superb modulation with hydro air, provide cooling and switch to electricity, so you’re on the right path. Adding a boiler for that was the issue. Maximum expense for limited gain.

hot_rod · April 2022

some good info on heat pumps here
https://www.caleffi.com/sites/default/files/file/idronics_27_na.pdf

Jamie Hall · April 2022

I'd go with option 2, but unless you have a very large lot skip the solar PV, at least as a power source for the heat pump. A good 50K heat pump will draw about 7KW of power, which would require at least 35 square meters of array -- in direct sunshine. You can get that much heat from a window with an area of 7 square meters (that's direct solar, which is far from dead -- just not glitzy). If you account for the minor problem of nights and clouds, in most of Ontario it would be prudent to have 840 square meters of collector, and about 500 KW-hours of battery storage.

[deleted]

Now to the comment that solar thermal being a lot of hassle -- that's quite true if one decides to try and do it with solar collectors and pumps and storage tanks and all. Passive or semi-passive solar, however, is simply a matter of intelligent architecture for new construction, at little or no additional expense (as a retrofit on an existing building, it is indeed a hassle). But that, really, is another matter.

Hot_water_fan · April 2022

@Jamie Hall this divisiveness isn’t helpful. Solar PV is not green signaling- those kWh are real and they displace dirtier kWh. Utility scale solar is more cost effective than residential scale, but that’s a separate discussion. Similarly, solar PV does not need battery backup, yet you insist on mentioning it. It might be desirable for some, but it’s totally unnecessary at this point for the vast majority of grid connected homes in the US and Canada. If battery backup was required, then it would also apply to passive solar too.

Jamie Hall · April 2022

I have deleted the offending paragraph, and I hope that those who were offended will accept my apologies.

Brad Barbeau · April 2022

Thanks, lots of good stuff here and the Caleffi doc is great, just working through it now. There are some government grants (PV or HPs) available in Canada right now too.

So, air to water rather than air to air? It seems that the water option would allow more flexibility with the two air-handlers/furnaces (assuming to keep those in place) since one HP could feed both?

hot_rod · April 2022

Correct, moving and storing energy is much better accomplished with water. Certainly a fan coil could be added for cooling moving some air for filtration, humidity, etc.
As for PV really no need to have an array large enough to cover the entire HP load. I suspect you will stay connected to the grid? So the PV like ST is to offset some of the load.

Plenty of RE naysayers or haters out there, most have never lived with PV or ST. Do the research, find the facts based opinions, decide what is right for you and your family.

Heating and Cooling in Ontario

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