In Ontario, heat pumps are fast becoming the technology of choice for both home heating and air conditioning. Why is this the case, and why is a heat pump the best choice for the Mindemoya Old School? Before answering that question, what exactly do heat pumps do?
Heat pumps do the work of heaters as well as air conditioners. They heat homes by moving heat from outdoors to indoors. How does that work? First, heat pumps consist of two pieces of equipment, one inside and the other outside. The unit that’s outside might be underground or it might just sit beside the building. They are called ground-to-air or air-to-air heat pumps.
Heat pumps work like air conditioners or refrigerators. It’s not magic, it’s just using the idea that heat always moves from hot to cold. Think of a refrigerator that moves heat from inside the refrigerator into the kitchen, even though the inside of the refrigerator is colder than your kitchen. The coils in the fridge contain a liquid that’s colder than the air in the fridge, so the liquid warms up and then it’s pumped out the back and warms your kitchen. Stand behind a refrigerator when it’s running and you can feel the warmth.
Heat pumps use the same idea. They draw heat from the air outside and feed it to the inside of the building. The refrigerant is colder than the one used in a refrigerator — say at -35℃. As long as the temperature outside is higher than that, heat automatically moves from the air into the coil. In practice, heat pumps these days can work at temperatures down to -25℃. In the depths of winter, when the temperature may dip below that, back-up heating like regular electric heaters is needed. On Manitoulin Island, an average year has only five to seven days with temperatures below -25℃, and the climate is getting warmer.
Why are heat pumps better than other heating and cooling systems?
Unlike most other systems, they are dual-purpose: Heat pumps work both as heaters and air conditioners.
Heat pumps are much more efficient than the old baseboard heating -- up to three times more efficient. Heat pumps stop when outside temperatures are below their design temperature..
Propane furnaces produce a lot more greenhouse gas emissions than heat pumps. Propane and natural gas are fossil fuels that are less polluting than oil when burned, but far more polluting than electricity in Ontario. In general, burning propane emits about seventeen times as much greenhouse gas emissions as heat pumps. In practice, these numbers vary a bit depending on the particular equipment.
Aren’t Heat Pumps Expensive?
As with most measures that save energy and reduce greenhouse gas emissions, the upfront costs are higher. Insulating your home costs more than not insulating, LED light bulbs cost more than incandescent, EV’s cost more than vehicles that use gas, and so on. The savings are in lower operating costs, and homeowners may qualify for grants for reducing their greenhouse gas emissions. But they pay for themselves over time.
My own home on Manitoulin Island is one example. In 2019, I installed a heat pump as my main source of heat, with my old oil furnace as backup for cold winter days. My oil expenses fell from $2600 in 2018/19 to $500 the following year, even adjusting for slightly different winter weather. The cost of electricity and oil in 2019/2020 saved me $1479.70 in heating costs. Using current costs, I estimated a payback period of less than six years — by the winter of 2025/26 it will have paid for itself! Meanwhile, newer heat pumps are even better, working efficiently at lower temperatures than mine. I figure the heat pump in my home reduces my carbon dioxide emissions by a whopping 72%, dropping from 6.5 tonnes to just 1.1 tonnes of carbon dioxide in the first year. Newer heat pumps can reduce carbon dioxide emissions even more.
Greenhouse gas emissions from three energy sources
Propane: 39 litres are required, releasing 61.15 kilograms of greenhouse gases. |
Heating oil: 25.8 litres are required, releasing 68.37 kilograms of greenhouse gases |
Electricity using baseboard radiators: 277.78 kilowatt-hours are required, releasing 6.94 kilograms of greenhouse gases (25 grams per kWh in Ontario) |
Electricity using heat pumps with 250% efficiency: 111.1 kilowatt-hours are required, releasing 2.77 kilograms of greenhouse gases. |
The above comparisons are extrapolated from the B.C. report: 2020 B.C. Best Practices Methodology for Quantifying Greenhouse Gas Emissions.
Jan McQuay
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