[BorgHunter]

Modern heat pumps can work in very cold weather, but they're much less efficient, which is reflected in their COP numbers. In my house in Chicago, we have a hybrid system--the heat pump works down to 20F or so, and we have a natural gas furnace for colder times. Natural gas is very cheap here, so this is the most cost-effective solution at the moment. I'm very eager to electrify and remove my dependence on natural gas, but I think it will be at least a few more years unless there's some breakthrough in cold-weather heat pump efficiency, or an enduring spike in natural gas prices--last time I did the math, the breakeven point for electrification here is around a COP of 4, which no heat pump can do at typical Chicago winter temperatures.

If I were building a brand new house, I probably would do it 100% electric. But most people here already have natural gas furnaces, and when they reach end-of-life they're usually replaced with another natural gas furnace. Hybrid systems like mine are catching on, but it will be a while before 100% electric is commonplace here.