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Is it likely cheaper to use a space heater than full central heating if you literally dont even use much of the space in the house that you never like go anyway? (lemmy.world)

submitted 1 year ago by cheese_greater@lemmy.world to c/asklemmy@lemmy.ml

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[–] Deconceptualist@lemm.ee 4 points 1 year ago* (last edited 1 year ago) (2 children)

Some highly efficient central heating can have greater than 100% efficiency

How's that supposed to work? What values are being compared? As a general engineering principle, I thought all transformations include at least a little loss.

[–] LastYearsPumpkin@feddit.ch 4 points 1 year ago (2 children)

Because in the most efficient systems, you aren't creating heat, you're moving heat.

https://youtu.be/7J52mDjZzto

Just as a made up example - with a space heater, you could get 1000 watts of heat from 1000 watts of electricity, or you can move 1500 watts of heat with 1000 watts of electricity with a heat pump.

It's pretty neat.

[–] Junkers_Klunker@lemmy.world 4 points 1 year ago

The heat pump in my home has an SCOP of 4.9 under perfect conditions and ~3.5 under normal conditions, which means 1kW of electricity in equals 3.5-4.9kW of heat out.

[–] Deconceptualist@lemm.ee 1 points 1 year ago

Ohh okay, well yeah if you count heat pumps that's another story. I was only thinking in terms of energy generation (usually from burning something or electrical resistance).

Thanks for the video, I think I saw that channel once and it was interesting so I look forward to watching it later. It's been a long time since my thermochem course so it'll be good to revisit some concepts.

[–] ImpossibilityBox@lemmy.world 3 points 1 year ago

If they are speaking about heat pumps then they are technically correct. A heat pump uses energy to move heat from one location to another instead of converting heat from form to form. It's the conversion that causes inefficiency.

I'm not nearly smart enough to properly explain the physics of it but there are plenty of articles and YouTube videos available if you want to go down that rabbit hole.