Figured it would be good to post my geothermal experience to help those looking to have geothermal installed in CT. My house was built in 2006 or 2007, 2,400 sq ft (1st and 2nd floor), ICF walkout base (half finished with the garage in the other half) which makes up another ~800 sq ft. My setup was 2 air handlers, one in the basement and another in the attic to service the house. The unit in the attic was tucked away in a terrible location, making it impossible to service, and I had my suspicions that the duct work wasn't entirely air tight, mainly with the connections to the air handler not being correct. My AC units and boiler were also oversized for what was needed, causing us to use a lot of extra energy and short cycling our equipment and witht he poor installation of the attic unit, I was climbing into the attic every month to change air filters. With the useful life of the AC units starting to approach (we started having failures and I wanted to get ahead of them), the oversized equipment and improper attic air handler installation, I started to look at geothermal as an alternative solution. We had solar installed in 2019 and our production outpaced our usage, making it so we were giving back some power every year. What wound up being installed was a 4 ton hydron module revolution 2 with desuperheater and 10 kW aux heat strip, 80 gallon hybrid water heater and 40 gallon buffer tank. We had two (2) 300 foot vertical closed loop wells installed and the system is expected to keep the house at 70 degrees inside to a minimum outside temperature of 8 degrees. To connect the 2 zones, we expanded an existing chase inside the house and had ductwork run from the mechanical room to the attic to tie into the existing ductwork, eliminating the attic air handler. The wells were installed in March 2021 and the rest of the work was done in May 2021. Using the geothermal throughout the summer, our energy usage dropped by 30-40% while keeping the house cooler. Its only early fall with the system, and I expect to see higher electric bills through the winter, but I expect to save between $1,000-1,500/year over what we would be paying in oil/electric while keeping the house warmer than we did with the oil boiler. Overall, we have been very happy. The house is cooler in the summer and warmer in the winter, the humidity levels in the house are much more even and at the end, we're going to save money and no more needing to worry about shoveling the path to the oil fill pipe and keeping an eye on the tank. From a cost perspective, it is certainly a higher upfront cost, but after rebates and tax credits, will probably wind up being a difference of around $5k over the cost to just replace my AC units and oil boiler with newer, correctly sized equipment. I did have my previous oil company quote a system, but it was not an apples to apples, so I don't have an exact figure for the true replacement system. Additionally, if I had went with an oil boiler and AC unit, I would have looked at something liek a system 2000 to get better efficiency and lower my oil usage as much as possible. For us, this relatively small upfront cost difference was worth the benefits we have seen, both quantitatively (more comfortable house) and qualitatively (no more oil deliveries or oil tank in the basement).