“a good furnace turns about 95 percent of the energy in the fuel it burns into heat for the house. A heat pump uses its input energy to move about 200 to 300 percent as much energy into the house in the form of heat.”
“You put 100,000 BTU of fossil gas energy into a furnace, and you get 95,000 BTU of heat delivered to the house. You put 100,000 BTU of electricity into a heat pump, and you get 200,000 to 300,000 BTU of heat in the house.”
“In the case of electricity generated by burning coal, the efficiency at the plant is 35 to 40 percent. Factor in the losses as the electricity goes from the plant to your house, and you’re down to about 30 percent efficiency. Gas-fired power plants are better but still only about 50 percent efficient”
“When you use that electricity in a heat pump, you get about three times as much heat as electrical energy used. That brings the net efficiency back up to the 90 to 100 percent range. And that’s about the same as a high-efficiency furnace.”
“Another big difference is that the rates utilities charge for electricity and gas are different. Even when you have a super efficient heat pump going up against an old, inefficient furnace, the furnace may win on cost. That’s because gas rates in many places are really low.”
https://www.energyvanguard.com/blog/is-a-heat-pump-more-efficient-than-a-furnace/
100,000 btu’s in, get 300,000 btu’s out? That blog is pumping something but I’m not sure it’s heat.
Your points on heat pump efficiency are entirely accurate, but you didn’t include an important limitation of heat pumps. As the outdoor temperature nears freezing, frost can form on the outdoor heat exchanger. This reduces air flow and decreases the efficiency of the unit. At some point, it will cease to work. There is a built in defrost cycle in newer units, but all of the defrost energy further reduces the efficiency. When this happens, backup resistance heaters turn on but these are much more costly to run than the heat pump alone.