Mitsubishi sells heat pumps that produce 14kw of heat output all the way down to 5f at a COP of 2.3.
Resistive heat has a COP of 1, by definition.
Do you know the size of your oil burner? It's likely over 20kw output.
It's not that pumping heat cannot work sufficiently at cold temperatures, it's that you are expecting the electric car rated 100 horsepower to go as fast as the gas car rated at 300 horsepower.
An oil burner sized to the same output as the heat pump also would not keep up.
If you installed two of those Mitsubishi heat pumps (which would require two independent 240v circuits), you would be at 28kw output and would not need resistive heat strips. These units also claim 75% rated capacity at -13f so that would be about 21kw of heat output even when very very cold.
If your resistive heat strips activate at any point other than extreme weather events or emergencies, your "system" is not sized properly. They are a massive waste of power and money.
A big part of the problem is that the contractors who are essentially the point of sale for these systems are just obscenely dumb about them. They will sell you utterly undersized units or sell units that aren't rated for cold, as well as just install things so poorly that they drain condensate into your walls and cause mold issues. They had similar problems with Oil burners, but at least those they tended to upsell bigger systems so their ignorance didn't matter. They seem very bad at doing the planning or design required to actually spec out a system, so you have to be your own engineer.
>and that is what the industry needs to work on.
I don't know how the industry is supposed to force contractors to read their very very clear documentation, or follow the very clear instructions (of boiler manufacturers no less) of "You must measure heat load to accurately size a heat appliance".
Mitsubishi sells heat pumps that produce 14kw of heat output all the way down to 5f at a COP of 2.3.
Resistive heat has a COP of 1, by definition.
Do you know the size of your oil burner? It's likely over 20kw output.
It's not that pumping heat cannot work sufficiently at cold temperatures, it's that you are expecting the electric car rated 100 horsepower to go as fast as the gas car rated at 300 horsepower.
An oil burner sized to the same output as the heat pump also would not keep up.
If you installed two of those Mitsubishi heat pumps (which would require two independent 240v circuits), you would be at 28kw output and would not need resistive heat strips. These units also claim 75% rated capacity at -13f so that would be about 21kw of heat output even when very very cold.
If your resistive heat strips activate at any point other than extreme weather events or emergencies, your "system" is not sized properly. They are a massive waste of power and money.
A big part of the problem is that the contractors who are essentially the point of sale for these systems are just obscenely dumb about them. They will sell you utterly undersized units or sell units that aren't rated for cold, as well as just install things so poorly that they drain condensate into your walls and cause mold issues. They had similar problems with Oil burners, but at least those they tended to upsell bigger systems so their ignorance didn't matter. They seem very bad at doing the planning or design required to actually spec out a system, so you have to be your own engineer.
>and that is what the industry needs to work on.
I don't know how the industry is supposed to force contractors to read their very very clear documentation, or follow the very clear instructions (of boiler manufacturers no less) of "You must measure heat load to accurately size a heat appliance".