System Performance on very hot days (above 100 degrees) I am considering installing a WaterFurnace Geothermal system at my house in CT to replace a Hallmark oil furnace. I have been told that on hot days (100 degrees or above) most units will cool the house up to 80 degrees but can't go below that. I have tried contacting WaterFurnace to get some answers on this issue but it is quite difficult to get any replies from them (email or phone calls). Has anyone had any problems along this line? I wonder if this is even a consideration? Again my concern is mostly on the cooling aspect of this system (or any other geo system for that matter) and how it will perform on hot days. The installer I believe will go with a 4-5 Ton unit for a 2500 sq. feet home.