How is a heatpump more economical than natural gas? I am in bay area and it can cost anywhere from 15-20 cents a kwh for electricity.
Heat pumps are 3-4 times as energy efficient as a gas furnace. However, PG&E charges 7-8x as much per kWh of energy in electricity form as it does in fossil gas form.
When you have your own solar and storage, it can be as cheap as $0.04-$0.07 for the solar. And depending on the storage vendor these days, it can be anywhere $0.05-$0.15 per kWh that gets stored and discharged. At those rates, it can be cheaper than gas.
This depends totally on the outside temperature. Larger, more expensive heat pumps can stay efficient down to lower temps. However, they all have a point where they become less efficient than resistive electric heat.