Geothermal Heat Pump Installation in a Single Family Home

Can you describe your home and its mechanicals?

A: Our home was built in the late 1990s and is 2+ stories, with a half-finished basement. It totals about 2300 square feet. We had whole-home central AC (with ducts) and a propane furnace.

What was your motivation for switching to a geothermal heat pump?

A: Our central air needed to be replaced, and our furnace was aging, more than 20 years old. We added up the combined costs of purchasing both of those systems plus the installation. Then we looked at the cost of geothermal, which -- once we subtracted the utility rebate and tax incentives – seemed pretty reasonable.

The most convincing aspects of the new system were (1) knowing our heat would no longer be dependent on fluctuating petroleum prices and (2) we wouldn’t need to monitor the availability of propane, which had been tight on occasion the prior winter.

Did you have to do any prep work?

A: The prep was pretty minimal. Outside, the well and septic systems didn’t interfere, and our yard was mostly clear already. Since the heat pump pipes would enter the house where the AC had come through, we had to remove the old AC unit. The installers just had to dig a bit near the corner of the house where the pipes would come through the foundation.

On the inside, the electrical panel was able to re-use the breaker locations and circuits from the prior HVAC units. In the basement, I had to make sure there were no obstructions that would interfere with the pipes connecting to the heat pump.

What system did you purchase?

A: The heat pump we purchased is made by Enertech. It’s a 5-ton “closed loop system” that circulates fluid through flexible, vertical pipes that go down 250 feet into the earth.

How did the installation process go?

A: It was pretty impressive.

In the yard, the trenching and digging took about a week. The excavator that dug the trench was fairly compact and was steered by remote control. It was small enough to pass beneath tree branches in the yard without damaging anything.

Inside the house, the installation was unfortunately delayed about 2 months due to a personnel shortage. But once they were available, it only took a few days to complete (electrical work, removal of the old furnace, installation of the heat pump, connection with the pipes, filling the pipes, adding a couple additional ducts, and setting up the new thermostat).

What’s your impression of the system now?

A: We have had a tremendously positive experience with the geothermal heat pump and have been delighted with it.

Two noticeable differences were (1) a much stronger fan and air circulation from the blower and (2) the winter air being cycled was not dry like it had been when our furnace was burning propane. Otherwise, the blowing was louder than before, but there are settings to help with that and we got used to the white noise of it. The new thermostat and the heat pump allowed us to access a lot of data about the system operation, which was interesting to look through.

How do the systems compare?

A: Comparing the kWh from the same months in the prior year, we actually used significantly less electricity over the summer compared to the old AC system. For heating months, the electrical use was higher by comparison, but no more than +600 kWH a month (about $120) compared with winter propane costs, which were about $180 per month.

Note that we do still have propane, which supplies an ambient fireplace and grill.

Any tips or recommendations?

A: In general, there isn’t much reason to change the thermostat temperature. We lower it a little for sleeping comfort, about 4 degrees over day/night. Keeping temps steady is the best way to use this type of system.

How do you feel about the investment?

A: First off, the peace of mind for the independence from propane prices has been very satisfying! The cost of this system minus the estimated costs of a furnace replacement and AC replacement should take less than 10 years to break even. Depending on prices of oil and electricity, it could break even sooner. We are now looking into solar panels, which are very complementary to systems like this, as a way to further reduce our monthly energy costs.

It’s significant that the geothermal loop will always perform with more efficiency at the extremes of cold and hot because of the more normalized temperature of the earth. But even more significant is that the LIFE of the system is super long. Some parts of the system are under warranty for 60 years! Because the pipes are buried, the system doesn’t have the same wear from combustion /soot or from corrosion.

It will be a very reliable design for the foreseeable use of our home!