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One unfortunate situation is that the word “geothermal” is overloaded for personal use. On one hand you have geothermal power, which is as you describe. On the
by ashtonkem 5y ago
One unfortunate situation is that the word “geothermal” is overloaded for personal use. On one hand you have geothermal power, which is as you describe. On the other hand you have water source heat pumps which are often described as geothermal, but which are completely distinct from the form described in this article.
Water source heat pumps work everywhere, and they seek to use ground-water temperature anti-freeze in a closed loop as the output from a heat pump. So rather than having an AC dump heat outside (or cold for outside for reversible systems), heat is extracted from or dumped into the ground. Expensive to install ($30k seems a common mark), but very efficient and viable everywhere.
- zrail 5y agoWe have a ground source heat pump at our house. It has a bit of a learning curve vs a traditional ac but it's very efficient. The 26% federal tax credit and low interest state-supported financing take a bit of the sting out of the project but it's still not cheap.
- ashtonkem 5y agoWhat learning curve?
- zrail 5y agoPrimarily that it can hold temperature extremely well but its significantly slower at changing temperature than a conventional AC system. Our early attempts to use setbacks resulted in more energy usage as it shifted into more intense stages more often. At this point we basically touch the thermostat once per season change, when we shift from heat to cooling or vice versa.
- skybrian 5y agoInteresting. Why is it less responsive than an air source heat pump?
- zrail 5y agoThis is actually more of a problem with heat than cooling. The system doesn't output really hot air like a gas-fired furnace, it's generally closer to the temperature that the thermostat is set to. If you set the temperature differential more than a couple degrees the system will kick in it's auxiliary heating source (usually electric heater strips) which are so much less efficient than the heat pump that any energy savings you gained by setting the temperature back are almost immediately lost.