this post was submitted on 27 Jul 2023
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Sales are growing so quickly that some installers wonder whether heat pumps could even wipe out the demand for new air conditioners in a few years and put a significant dent in the number of natural gas furnaces.

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[โ€“] Space_Can@lemmy.blahaj.zone 15 points 1 year ago* (last edited 1 year ago) (1 children)

Mechanical engineer here!

What the OP is referring to as "Efficiency" is what's known in the industry as COP (coefficient of performance).

A system's COP is equal to the amount of useful heat energy supplied or removed by the system divided by the amount of energy used to do that work.

If your heat pump uses 10 Joules of electrical energy to move 40 Joules of heat energy from the outside into your house, that heat pump is operating at a COP of 4 (or 400%).

Only heat pumps can have a COP of >1, due to conservation of energy. A traditional gas or electric heater uses combustion or electrical resistance to lossily convert electrical or chemical energy into heat energy.

[โ€“] Rodeo@lemmy.ca -5 points 1 year ago (1 children)

So he's not talking about efficiency.

Please explain to the down voting morons why 100% efficiency is impossible.

[โ€“] Space_Can@lemmy.blahaj.zone 7 points 1 year ago (1 children)

If everyone in the world had an engineering degree the distinction might have been important, but complaining about it in this context is just pedantic.

[โ€“] Rodeo@lemmy.ca 0 points 1 year ago (1 children)

I really don't agree with that. "Baseboard heaters are 100% efficient" is an objectively false statement. And efficiency is a very common and basic concept that doesn't require a degree to understand.

I think instead of just dismissing it as pedantic, people could learn something.

[โ€“] nebula@lemmy.ca 1 points 1 year ago* (last edited 1 year ago) (1 children)

Maybe try looking it up.

Electric resistance heating is 100% energy efficient in the sense that all the incoming electric energy is converted to heat

[โ€“] FullOnElectric@mstdn.ca 1 points 1 year ago

@nebula @Rodeo

Hereโ€™s how to compare baseboards to heat pumps.

Baseboards create heat through resistive loads. As all the energy creates heat, you can say they are 100% efficient, but that is misleading if you take that to be good.

Heat pumps simply move heat, in either direction, to heat, or cool, and they do this using 1/3rd the energy.

Todayโ€™s heat pumps work at much lower air temperatures, can also use ground loops, or exchange heat from water bodies. #HeatPumps