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In 2017 there was still a 30% Federal tax credit for residential geothermal installations, and since we bought a big house with HVAC units right at the edge of their life expectancy my (accountant) wife talked me into replacing everything with geo.

We opted for the Climate Master Trilogy (Heat/AC/Hot Water) systems, a pair of 4 ton units, and a 3 ton split system for the upstairs - that's because there was no good way to get the geo piping up there, so we installed the heat exchanger/heat pump downstairs and reused the line set for the old AC system to take geo cooled refridgerant upstairs to a more traditional space pack, which has gas back-up heat.

We chose Gallagher/Hauser HVAC to do our installation, as the local company with the most experience. Their work has been technically quite good, but their customer service (for us) has been abysmal from start-to-finish, with scope creepy, cost overruns, and schedule delays at every turn so I would not recommend to anyone. For the kind of money we spent with them it's shocking how little regard they gave even the simplest requests.