If you go GEO make sure it is the proper size for your home. I had one installed in my 3 level farm house, we built in 1973. Burned wood until spouse passed in 2010, then well went bad in 2011, was convinced to save lots of $$ to do GEO.
WELL, the unit was not big enough for my square footage and was sending me to the poor house at close to $400 to heat at 68°. Had to have it removed because it was running most of the time on the electric assist, which is very costly. 5 dealers checked it all out---runs perfectly-----only needs to be in a smaller house to save any money. It was running my new well so much, it turned all water outlets, bathroom bowls orange, not a problem since it was removed.
So make sure it is bigger than what your square footage says you need. I should have had 2 units put together for the size of my home.
Am not a fan of the dealers around me, when they tell me I need to have $20,000 in improvements to make it work properly.