[jackcarter]

A heat pump warms a home more efficiently than using the same amount of electricity for resistive heating. It can do this because it's not generating the heat from scratch; it's moving heat from outside to inside.

https://en.wikipedia.org/wiki/Heat_pump#Performance

[xattt]

A local company has developed a heat pump with a thermal energy storage system. Not sure how they do this, but I imagine there is some sort of insulated cinder blocks on a secondary loop that shuttles heat/cold to where it needs to go.

(1) https://stash.energy/en/product/

[folmar]

They try very hard not to be specific, but the industrial heat accumulators are usually just water.

[xattt]

> … heat accumulator

Thank you for helping me learn a new HVAC term!

[OJFord]

I know. It's only >100% 'efficient' if you ignore the input of 'outside heat'. That is not a normal calculation, and not really called 'efficiency'.

It's desirable for multiple reasons, of course, but it's not efficiency.

[pmoleri]

Unfortunately by that metric other electrical heaters tend to 0% efficiency because they are not making use of the virtually unlimited energy outside the buildings.

The 400% metric let's you compare with other heaters, the 100% is kind of useless.

[OJFord]

They're not using them as an input, so.. obviously they're not included in the input/output calculation?