That doesn't math all that well. The coefficient of performance of a heat pump is better when the outdoor temp is higher - did you mean the temp outside is -above- 20F?
You're also assuming time of use billing, I assume.
I don't disagree, btw - gas is cheaper than a heat pump for me also, which makes me sad. My only point was that you have to compare against them and not resistance heating. (That's slightly wrong - if I were to use a heat pump during the shoulder season and my boiler when it's colder it would be cheaper in operating costs but lose on capex)
You're also assuming time of use billing, I assume.
I don't disagree, btw - gas is cheaper than a heat pump for me also, which makes me sad. My only point was that you have to compare against them and not resistance heating. (That's slightly wrong - if I were to use a heat pump during the shoulder season and my boiler when it's colder it would be cheaper in operating costs but lose on capex)