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Comment by phreeza | Hacker News Reader

Is that really geothermal, or is it a heat pump? A heat pump just uses the thermal mass of the earth to provide more efficient electric heating and cooling, it doesn't heat using geothermal power.

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Ground source heat pumps are generally considered to be “geothermal”.

You're not wrong; however that is an unfortunate misnomer since ground source bore holes (along with horizontal soil collectors and lakebed collectors) on the order of 100-300 m deep are still utilizing heat from the sun stored in the ground, and not heat produced from Earth's core.

I'd say it's a pretty good idea to not conflate the two by using more precise language, even if not doing so might be "technically correct".

Not in English.

The manufacturers of ground source heat pumps use the term 'geothermal' in English: https://www.waterfurnace.com/residential/products/geothermal... https://enertechusa.com/geothermal-product-catalog/ - the term is confusing though

I installed a ground sourced heat pump a couple of years ago, and my heat pump manufacturer refers to it as geothermal: https://www.waterfurnace.com/switch . Most people don't think of this as 'geothermal' however so I avoid using the term.

It's a mix of geothermal energy (extra heat), and insulation/thermal mass abitrage. Several hundred tons of rock/stone/soil are a great insulator, and are going to be consistently above freezing, which means you get a munch higher starting temperature for heatpumps if the alternative is freezing air.

In summer the ground is much cooler than the air, so it outperforms an air source heatpump for cooling the house too.

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