Our Furnace is an Accessory Now

As one of the first participants, under the Greys for Green initiative “Heat Pump Pilot Program”, in Briarhill, we recently replaced our air conditioner with an Air Source Heat Pump. The installer told us that the furnace was now connected to the “accessory” wire on the thermostat. This means is that we will switch the thermostat to Accessory mode when the outside temperature drops below -8C, or if the house doesn’t feel warm enough. The main job of heating and cooling belongs to the Heat Pump, and our furnace is now an accessory device. It is the back up heat source, not the primary source.
We installed a heat pump to reduce our carbon footprint. Natural gas is a prime source of carbon emissions in most Canadian homes. Switching to a heat pump is our way of trying to be part of the solution to the climate emergency. While we are reducing our use of fossil fuel, it turns out that we will save money along the way too.
In 2021, based on historical temperatures, if we had had a heat pump, the furnace would have run for 667 hours when the temperature was below -8C. The rest of the heating (2,823 hours with temperatures between -8C and 18C) would have been done by the Heat Pump. That’s 80% of the total heating hours. The savings – 590.2 cubic metres of natural gas and $705 in both electrical and gas bills. More importantly, we would have reduced our carbon emissions by 2,994.6 Kilograms! Of course, the future impact on savings will be affected by future increases in carbon pricing, electricity and natural gas and changes in weather.
The furnace deserves its “accessory” title.
Next spring, we will let you know the results of the pilot in terms how the Heat Pump worked through the winter season and how it met our above expectations.

Here is what it looks like.

SEER: Seasonal Energy Efficiency Rating (Cooling Efficiency)
HSPF: Heating Seasonal Performance Factor
The above hours have accounted for the Time of Use (TOU) price of Electricity and Efficiency Factor of the heat pump.

This article was also published on justayincaledon.com. View full article here.