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Gas to electricity efficiency is low so you loose more then half the energy when producing electricity from gas. Using a 90 percent efficiency furnace to heat water directly with gas is the better solution.

Assuming your electricity comes from gas plants.

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Heat pumps can have COPs above one so if your entire electrical grid was gas fired then youd need a COP of around 3 to break even which is doable.

The grid is getting greener which means you win by even more if you electrify everything.

That's what I've seen. Heat pump water heaters cost about the same to run as gas units. And yes the advantage is they don't fundamentally use natural gas so they are 'green' as the grid they are tied to is.

However if you heat with heat pump you are getting more than 3 times more heat than electrical energy you used. So despite getting only 0.5 energy by turning gas into electriciy you are getting 3*0.5 = 1.5 of heating and you could go in reverse and get the cooling when you need it.

If you have a gas line to your home the most efficient way of heating would be to have co-generation gas turbine than makes heat and electricity and then use the electricity produced to power heat pump.

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