In my area it's about 2.6x so a heat pump only needs to have a COP of about 2.4 to equal the cost of natural gas per unit of heat delivered when compared to a 9

In my area it's about 2.6x so a heat pump only needs to have a COP of about 2.4 to equal the cost of natural gas per unit of heat delivered when compared to a 90% efficient gas furnace. These modern air source low temp heat pump can maintain a 2.4 COP down to about 17F. Note my area is pretty warm (FL) so even though I have natural gas to the house for cooking and hot water I do not use for that as my air heat pump works very efficiently in the cool temps here. I have resistive heat as a backup and it never turns on. Geothermal heat pumps can maintain 3-4 COP year round in any temp then your easily surpassing natural gas even at 3x the cost.