- how deep was the trench leading up to the pond?
- is anything done to keep the coils in the pond from moving around?
- I assume you are replacing an existing system. If so, did you compare costs for replacing the old system with a conventional one? (I'm curious about upfront cost comparisons)
The trench is at minimum 6 feet deep.
The coils are held in place by their own weight filled with fluid and with 6 large concrete weights around the outside of the loop assembly.
Compared to our old system (a high efficiency LP furnace and an older AC unit) the annual savings in energy costs averages over $3000 per year. This includes the savings accrued from moving the house HE furnace to the shop. The shop currently has an old LP furnace with a chimney.
The cost for the system is $17500. Including the 30% federal tax credit the system is paid off with 4 years energy savings.
