Long term review of Geothermal Heating and Cooling
Jun 28 2022 4 min read (834 words)
VP of Product Management
Historically, geothermal (or ground source) heat pumps were difficult to install with a limited of HVAC companies capable of installing. In the past 5 years, geothermal has been increasing in popularity due to its high efficiency compared to gas, oil and electric heat and small carbon footprint (no burning of fossil fuels). In honor of Earth Day, I'm sharing my real world experience of this alternative energy source and my journey to reduce my carbon footprint and not worry about increasing fuel prices.
My Personal Experience with Geothermal Heating and Cooling
Living in a more rural area in Connecticut, options were slim for heating options when building my new construction home in 2016. Lacking natural gas, our only major options were oil, propane or electric strip heat. Geothermal wasn’t mainstream yet so finding installers wasn’t super easy. We lucked out and ended up working with Glasco out of South Windsor, CT.
Energy efficiency is a major passion of mine, so our 2000 square foot colonial was a modular new construction consisting of 2x6 exterior walls with R21 insulation, all sheathing and studs glued and nailed. This resulted in minimal air leakage in our home. The attic has a fully vented roof with R60 insulation. We also opted for XPS foam on the exterior to act as a thermal break against conductive heat loss. The full build will be covered in a future article and we'll be sticking with the HVAC portion.
Geothermal HVAC Cost Breakdown
$26,950 Main installation including:
- 3.5 Ton Geostar dual stage heating and cooling system
- GeoFlo water pump
- dual zone thermostat and electronic dampers
- 10kw backup auxiliary strip heat whole house humidifier
- insulated ducting
$7,500 for 500’ of well drilling with casing for the closed loop system
$500 (estimated) for electrical work
After tax incentives: $24,115
A traditional oil/gas furnace plus central air and insulated ductwork ranged from $12,000-$18,000 for a new construction, so we were looking at a difference of $6,000 to reduce our fossil fuel reliance. Costs will vary depending on your location and how rocky your soil is. The size of your home and the estimated heat loss will determine the size of your heat pump, which will also affect cost.
Drilling was conducted during the fall of 2015 prior to the foundation being poured due to the location of wells being placed in the backyard. This may be a challenge for properties that have space restrictions.
In May of 2016, the house was set and the electrical work was completed HVAC installation began. Ductwork was run and the pump was connected. The pump itself was powered by a standard 15 amp outlet but the system itself required a 2-pole 40 amp breaker for the system and a 2-pole 60 amp breaker for powering the emergency strip heat (in the event the heat pump fails or needs to recover in temperature quickly).
The furnace itself lives in the basement and takes up the footprint larger than a refrigerator. The downside is that it does take up a bit of space in the basement, but the plus side is that there's no air conditioning compressor on the exterior of your house that is exposed to the elements.
A significant amount of time and effort went into the planning and execution of this. So how did this perform? After five years of usage, I've been finding my average usage going up as we continue to increase the temperature in the winter from a constant 68 degrees to 71 degrees due to recently having a child. Since geothermal heat pumps require electricity to run, my measure for usage will be in kilowatt hours (KWH).
Your mileage might vary depending on your climate zone and pricing. Connecticut has one of the highest electricity rates in the country at $0.22 per KWH. You can compare rates against other states here.
- On average 800-1100 Kilowatt per hour usage in the peak of winter heating both zones to about 71 degrees Fahrenheit. ($140-$194*)
- Summer averages about 500 kwh of usage cooling cooling both zones down to 70 degrees ($88*)
Note: Figuring 80% of our electricity was used by the HVAC system, I multiplied the total KWH *.80 *.22 to calculate the estimated cost of heating/cooling our home.
Below is the electricity usage for the past few years broken up by month with average temperature. The average temperature by month does not expose any of the extreme lows and highs of the various days within the month. This is our household's all-in usage, which accounted for other appliances in the house: 2 refrigerators, electric dryer, televisions, and computers. Our stove and hot water is propane so is not a factor in electricity usage. We do not run anything high current such as a welder or air compressor.
Note: April 2021 data and onwards contains usage gaps as we have offset my electrical usage with the introduction of an 8.8KW solar array. Separate blog article covering my short term experience on solar to follow, but with our generation rate and net-metering we're not paying for any heating, cooling and electricity cost. Breakeven timeline had been further shortened with the fuel fluctuation prices in early 2022.
Overall this was a worthwhile investment for my personal property. I would recommend it to others if they plan to stay in their residence for the longer term, but otherwise the breakeven point may not provide the best return.