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I think geothermal only works out IF you have your own excavator or backhoe. Meaning, you can do all the excavation yourself.

The other method is if you are already drilling a well for domestic water down 200’ into the ground. Then you run a loop in that 6” diameter hole in the ground.

When you decided on your solar array did you ever consider one of those free standing units that tracks the sun throughout the day?
I understand they are the most efficient available.
I assume they are also more expensive to install and maintain.

I did consider a unit that tracked daily with the sun. But I chose against it because I wanted less opportunity for mechanical failure. Instead, use that extra money to simply add more solar panels (assuming you have the space).

As it stands today, the only mechanical components in my entire solar system are the fans in my inverters. Of course, outside the solar system itself is the larger energy project that includes not just going solar, but the variable speed heat pump, hybrid water heater, and EV car. From that standpoint I'm depending on warranties to cover multiple mechanical parts.

Back to cooling and geothermal vs my system. A valuable part of my system is the hybrid water heater (built in heat pump) produces a byproduct of cold air. During the warm half of the year I duct that air into a new air receiver in the floor of the closet that my water heater is in. The end result is that every day, for the 2 to 3 hours the water heater runs, I have free cold air allowing my home's variable speed heat pump to stay in low power mode. And because the water heater runs at only 380W (as opposed to 4kW like a normal electric water heater), the total power load of my house is almost always within the 18kW capacity of my inverters to provide constant AC power from homemade DC power (either from solar panels or batteries).

In other words, the solar equipment works fine autonomously. The water heater is also good autonomously. And the variable speed heat pump works fine. But all of them together work better than the sum of their parts. I just don't see how I could use geothermal for dual purpose (to help warm the water tank while it helps cools the house) like I can use the hybrid water heater for dual purpose (cooling the home while it heats the water tank).

And, similar to geothermal but coming from the opposite direction, I utilize the heat in my attic. The air intake on my water heater is coming from an air duct from the attic above it. Basically, the water heater's heat pump doesn't have to work really hard to find heat in the air it takes in if the air is usually pretty warm (like attics usually are in Alabama). So God blesses us with free sun, thus I use it for power. And I have free heat in the attic (usually), thus I use it to optimize the water heater. And the water heater gives me free cold air, thus I use it to help cool the house 7 months out of the year (during the cold months I duct the cold air away from the living quarters).

Altogether it means my power bills average $80/month for an all-electric 2,300 sq ft home, including charging the EV to drive it 1,300 miles per month (local miles charged at home, not counting if we take it on a trip).