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Geothermal system?

Posted by gpaintjr (My Page) on
Sun, Dec 13, 09 at 19:42

We had a geothermal system put it our house in October so this is our first winter using it. Last week the temps here in N. Georgia got down to the low 20's and our system could not seem to get above 65 degrees. We set it back to 62 during the day and it comes back on at 5:00 p.m. to 68 degrees but it could never reach that temp. Is this normal???? We have LP gas as auxiliary but it is set to come when temps reach 10 degrees. Any help is appreciated.

Follow-Up Postings:

RE: Geothermal system?

No this is NOT normal!

In order to help you need to provide as much detail as you can about your system including design temperature, type, capacity, ground loop specs, flow rate, EWT & LWT etc. etc.

Wheres your installer in all this?


RE: Geothermal system?

Hi - this is our first winter using our geothermal system as well, so I am by no means an expert. However, our installers told us before we even put the system in that with a geo system, you need to get out of the habit of turning down your thermostat. The reason is that the air coming out of the vents is not nearly as hot as with other systems. It is a lower, more constant temperature. This is actually a more comfortable heat delivery than the hot blowing, followed by cold, followed by hot blowing.

However, because the air is not as hot as with traditional heaters, it is not designed to raise the temp quickly. Therefore you should not lower the thermostat when you are out of the home the way you do with a traditional system. They said you have to break this habit. This is a hard habit to break! We have been keeping our house constant for the fear that if it got too cold, we wouldn't be able to bring it up.

I will be curious to hear what other geo owners/ installers have to say.

RE: Geothermal system?

We set ours low in the winter (65 F) and high in the summer- high enough to never use the air conditioning. Once it's set we leave it alone.

Our Tranquity delivers air at about 95 F at the register. It's a softer flow than the old gas forced air system, and the house is more comfrtable at 65 with the geo than it was at 68 with the gas.

Most geo systems have backup heat sources to raise the temperature quickly if demand is not met rapidly enough, but the backup heat always costs more than running the heat pump itself. We have our backup disabled.

The system keeps the house right where we set it in sub-zero, windy weather. It's an old stucco house and has its problems with air infiltration and heat loss, but it had those with the gas, too!

RE: Geothermal system?

Set it and leave it. I set my new geo system at 68 and our old house remains an even temperature all day and all night. No more being chilly or cold spots. It's wonderful.

Geo systems are designed to run at lower speeds and at lower temperatures than conventional systems, and for longer cycles. Because of that, it takes longer to heat the mass of a house, but it's easy to keep it there. Raising and lowering the thermostat just ruins the efficiency of a geothermal system.

Go to and to learn more. I have found both sites to be great places to learn about geothermal. I am grateful someone directed me to them.

Good luck!

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