On top of that, the maximum theoretical COP for a cold source at -30c and a hot side at 35c is 4.7. Real world heat pumps usually get half of that, possibly eve

On top of that, the maximum theoretical COP for a cold source at -30c and a hot side at 35c is 4.7. Real world heat pumps usually get half of that, possibly even less for this extreme delta t, so around 2. Natural gas tends to cost less than half per unit energy compare to electricity, even less typically, so you'll never make back the capital costs. Of course if this technology matures to the extend it's much, much cheaper and you tend to have milder winters and hot summers it's good enough and possibly worth it, but we haven't gotten to maintenance and installation costs yet, as the 35c hot temp assumes underfloor heating or tons of fancoils which have their own issues, the fact that the heat pump must be massively overspectd to output enough heat in peak conditions etc.