Home heating and cooling are huge issues, and huge drivers of climate change (and no, I’m not going to bore you with statistics to prove facts that most of us are on side with).

This is mostly addressed to homeowners who might be replacing a heating/cooling system in the near future.

I’ve been grappling with this myself; I currently have an oil boiler *hangs head in shame* (the house came with it), but I couldn’t think of a really good alternative; natural gas is somewhat better, but is still a fossil fuel (and it would cost me about 10 grand to switch over), electric heat doesn’t use fossil fuels in Ontario; we have hydro and nuclear sourced electricity, but it’s expensive! I thought about geothermal heat pumps, but that would mean digging up my tiny backyard, ripping out all my trees (all 3 of them), and would cost about $30,000, and would have to be replaced in about 20-25 years.

What to do?!

About a year ago, another type of heat pump appeared on my radar; an air source heat pump. They run off of electricity, like a furnace does, but electricity is not the source of the heat, so they are cheaper than electricity, and cheaper than gas and oil in most places (a big check mark in favour right there), they are clean, if your electricity source is clean, and can run off of solar panels, and in my case, they will probably cost between $3,000 and $5,000 to install. Another big check mark.


As soon as I heard about them, they started popping up all over; my neighbour across the street has them, someone on the next street over installed them last fall, some friends of friends installed one at their vacation property, etc ...

Oh, and did I mention that they’re air conditioners as well?

Here’s the page from the Government of Canada’s Ministry of Natural Resources page;


They generally last about 15 years, which is comparable with most other heating systems.


Mitsubishi, Fujitsu and Daikin seem to be the big manufacturers, and Mitsubishi has a model which heats down to -25 Celcius (-13 Fahrenheit). Below that, and you need a supplemental heating system. I’ll tell you though, we didn’t get below -20 Celcius this winter in Toronto, and that was only a couple of times.

Generally, they are designed on a “mini-split” ductless system, which is ideal for older homes, like mine, that have no furnace ducting; there is an external compressor which can either be attached to the outside wall, or sit on the ground, if you have room. The interior units (and you don’t need one in every room), consist of “heads”, which are located near the ceiling, ceiling vent units which blow warm or cool air down, or floor units, which look a bit like modern radiators. They can also be used in radiant floor heating systems. And they can be used with an existing ducted system. Here’s a link to the Mitsubishi page;


A downside is that they use refrigerant; remember my first post on refrigerant management? Yeah; you need to have them installed and serviced properly to avoid refrigerant leakage. On a more positive note, there are less damaging refrigerants coming on the market, and there is also research in how to use C02 as a refrigerant, which would be a two-for-one benefit; not producing a green house gas, and in fact, sequestering C02. This might be “next generation”.


For anyone interested in looking at other articles, I suggest searching “air source heat pumps” in Green Building Advisor


And in CleanTechnica;



I’m probably going to be switching over in 2020, as I’m doing a twice daily check of the oil tank for leaks, and that’s getting old. If I switch to this newer tech, I can get rid of the oil tank, the boiler AND the cast iron rads that take up a huge amount of wall space.