But is it more efficient overall? Gas to elec, infrastructure losses, etc. vs just gas to heat?

Sure. A heat pump only needs to be 170% efficient to make back the generation losses. As for infrastructure losses, natural gas distribution has leaks as well.

Also, if the power plant is integrated into a CHP system to heat nearby households then generation gets back some percent.

Good point.

Methane leaks are much more environmentally damaging than often appreciated because methane is such a potent greenhouse gas.

Heat pumps are dramatically more efficient. A good gas furnace is 95% efficient. Meanwhile, a ductless heat pump can be 300%. They more more energy than they consume. That's the huge advantage.

Converting gas heat to heat pumps, even if they have a gas heat backup for worst case days in northern latitudes, would still be a big win in the net environmentally.

can heat pumps use underground sources as a cold (summer) / hot (winter) source?

Yes, of course if they're bi-directional. And theoretically, you can also use excess renewable power to heat up the soil in summer and draw on that stored heat in winter.

Yes, but at that point it's like running an AC during a hot Summer day. The compressor will be working very hard to keep up with -20.

Our leaders have lost their minds pursuing green purity. It's a religion at this point.

-20 - at which point the COP of the heat pump I linked to is still well above 1 - is equal to the coldest temperature on record in the locations I mentioned. Not the coldest daily maximum. The coldest temperature ever recorded, and the heat pump still wouldn’t require any backup system. Yes, it’s probably working hard at that point, but so? We’re talking exceptional conditions for the location.

And for the other 99.99% of the time the heat pump is so much cheaper to run it’s not funny - and in the long run you save even more when you’re not paying for all that gas infrastructure to be installed and maintained.

So you have all the heat pumps going on full blast on the coldest days, all together. It's a huge spike in energy demand. As long as the grid can deliver it fine, but when it doesn't the potential is catastrophic. Natural gas heating is far less grid dependent. Even if you lose power you could run a gas furnace with a small generator. Not the case with a heat pump.

Rationally speaking we can only turn the ship as fast as it can turn. Rushing and forcing things to happen that do not have a solid foundation (i.e. a suitable large and reliable grid) are just going to cause problems.

> So you have all the heat pumps going on full blast on the coldest days, all together. It's a huge spike in energy demand. As long as the grid can deliver it fine, but when it doesn't the potential is catastrophic.

Repalce heat pumps with gas furnaces and you have an equally true sentence, if "the grid" is the gas grid.

Gas usage also spikes on those cold days. You know what people do to prevent this being an issue? Storage. Nothing you couldn't also do with electric power.