Should I use a furnace for auxilliary backup?
I live in Ottawa and we’re in the process of getting quotes for both a full electric heat pump system (Mitsubishi Zuba) and a hybrid system that will keep us on natural gas. One of the companies quoting scared us away from the full electric system, saying we could be paying up to $1200 per month in hydro during the cold months, which would basically triple our annual heating costs.
I’m just wondering how much of your hydro costs have been offset by your solar panels. We don’t have solar panels so wouldn’t benefit from that. And we live in a colder climate than Toronto. Do you think our operating costs with a full electric system will be significantly higher than we’re currently paying with our natural gas furnace? Thanks for any insight you may have.
Answer from Green Energy Efficient Homes
I recommend going with a full electric heat pump system including auxilliary backup heat (resistance heating element).
I’m finding many HVAC companies try to scare customers away from heat pumps without really knowing what they’re talking about. In some cases they just pan heat pumps generally because they would rather sell you a furnace.
The figure they gave is a worst-case scenario where a polar vortex covers Ottawa for the full month and it’s -30C the whole time.
I’ve adjusted the settings on my heat pump so that it stays 100% on heat pump heat down to about -15C, which is still more efficient (in modern heat pumps – not so much in the 10+ year old vintage) than resistance heat. I do see “HP + electric” on my thermostat at times, usually when it’s below about -8, which means the resistance heater is running along with the heat pump. The heat pump occasionally has to switch the electric on for short periods to heat the outdoor coils to defrost them. Once it’s down below -15C it always says “HP + electric” and below about -23C it just says electric. But the number of days where it stays below -15C is limited and it hasn’t had a big impact on my operating costs.
With this setup, if I look at my utility bills from before and after I switched all my appliances from fossil gas to electric (furnace, hot water heater, dryer all switched to heat pump equivalents) my total energy bill has gone from $1956 the last 12 months I was fully on gas, to $1980 a year later and $2215 two years later. And that’s with the heat being on during the workday after the switch, due to the pandemic, whereas before we were all out during the day and kept the heat lower. So roughly a 10% increase while also increasing the amount of time running ful heat. Bear in mind that if you had stayed on fossil gas, you’d be paying increasing prices every year due to the carbon tax, so you’d probably see an equivalent or greater increase if you stay on that.
And I can’t describe how wonderful it feels to have moved our house to carbon neutral.
One last point – in my case the solar panels have nothing to do with my hydro bills, because I’m on the MicroFIT program, which was put in place by the Ontario Liberal government and cancelled by Doug Ford as soon as he came to office. The program pays me a set rate (in my case, $0.39 per kwh) for what I generate, independent of what I consume. (I have two power meters, one for generation and one for consumption.) The MicroFIT program was put in place to encourage people to install solar power systems. Since the cancellation of the program, the new option is Net Metering, where you have a single meter that goes backwards when you generate and forward when you consume. The only catch is any excess of production over consumption in a calendar year is zero’d out, so you never get money from the power company for what you generate, but it can offset your bill.