The article doesn't say just how much more expensive heat pumps are when comparing to gas furnaces. I live in one of the states at the top of that picture and just replaced my 20+ year old furnace and AC compressor. I specifically asked about heat pumps and they were reluctant to even price it out for me. It was over twice the cost. In addition they said the area I live in would almost certainly require an aux heat source, which they recommended gas for because direct electric heat is so horribly inefficient. I ended up going with the 98.5% efficient gas furnace, which also came with incentives and rebates from the power company.