I live in northern Louisiana and have a 4 ton 2 stage geothermal system with a 4 ton plate coil in 15' deep water in a large lake. My mid afternoon entering water temp is running 93 degrees F with an outside air temp of 95 deg. I calculate an cooling EER of 13.8 which is not as efficient as I had expected. I am considering converting to a closed loop well system to replace the plate coil in the lake. Anyone have any idea what EWT I could expect with four 150 ft deep wells?