Renewables became the second-most prevalent U.S. electricity source in 2020

Re:Renewables became the second-most prevalent U.S. electric... by agurk on Thursday July 29, 2021 @07:00AM (#27995041)

A key point to understand about a heat pump is that it can move a lot more (heat) energy than the equivalent it consumes. One joule of pumping could get up to six joules of heat moved[0] - so it could be represented as being 600% efficient. Burning gas can only generate a maximum of one joule of heat for every joule consumed (i.e. 100% efficient).

Getting six joules requires favourable conditions and a good setup, but the normal expected efficiency is considerably above 100%.

Gas is (normally - I'm on a variable tariff and being paid to consume electricity at the moment) cheaper than electricity per joule, but not so much that it works out cheaper than a heat pump to achieve the same effect.

[0] https://www.eec.org.au/for-energy-users/technologies-2/heat-...

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Re:Renewables became the second-most prevalent U.S. electric... by zbrozek on Thursday July 29, 2021 @07:56AM (#27995391)

Much depends on where exactly you are and who you pay for electricity and when. For me, under PG&E pricing, the running cost for heat pump heating ends up higher than with gas. And the equipment cost is much higher.

I'll end up getting it anyway when I get an AC system someday, but it'll have to run off solar to be worthwhile.

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