> In many places, natural gas is still more cost efficient, even if it isn't as efficient in terms of physics. As page where you can enter some numbers: * htt

> In many places, natural gas is still more cost efficient, even if it isn't as efficient in terms of physics. As page where you can enter some numbers: * https://www.heatpumpswork.com/cop-target https://www.heatpumpswork.com/cop-target Also, given a US zip code, how often the temperature may drop below 15F / -10C (which is a cut-off for many units): * https://www.heatpumpswork.com/cold-days https://www.heatpumpswork.com/cold-days A good HVAC contractor will create a design based on your building and location, and it will cover 99% of average days efficiently for heating and cooling: * https://www.greenbuildingadvisor.com/article/design-temperature-vs-degree-days https://www.greenbuildingadvisor.com/article/design-temperat... * https://www.airequipmentcompany.com/2021/what-does-design-day-really-mean/ https://www.airequipmentcompany.com/2021/what-does-design-da... For the remaining 1% it will basically have to run all the time to keep up. (In any given year you may not even get below/above the average outlier 1%.)