Hi, Brand new member here. I decided to join this blog based off the problems I'm having, that are similar to "Thundermustard" in a blog on this site http://www.geoexchange.org/forum/th...-winter-with-geothermal-still-not-happy.5790/. I had a general contractor install my geothermal system in our 3000 sf house last February ( House Facts*built in 1900, used to have base board heat, but was stripped of copper prior to me buying the house). I too have two goethermal systems, one for upstairs and one for downstairs. My system is a 3.5ton main floor Tetco Model#TST040B11AAANSS and 1.5ton Climate Master Model#PDW18GAADCSB upstairs unit, both sharing a 4000ft slinky loop consisting of 6 fingers burried 7' deep and around 10' between them. I'm running the racing fuel water mixture in my lines. The ductwork is brand new since the house was base board heat originally. I had outrageous bills right from the start but did't realize it until 3 months later when I found out my first two months of geo heat were estimate readings by the electric company. $140, $120, $2043 respectively for February, March, April. I discoverd that my electric heat was kicking on every time the geothermal was running, including in cool mode. The cause was that the emergency heat circuit was jumpered off of the compressor circuit in the geo unit and not wired into the thermostat at all. I unhooked the auxillary curcuit from the air handler until I figured out my issue late this fall. I fixed this in early November and to my disapointment my November bill was $703 and December was $835 and January will probably blow my mind. From previous conversations with my contractor I decided that my house was loosing too much heat, so I put plastic on all my windows, caulked any air leaks, and called Retrofoam to have my exterior walls injected with foam and my crawl space walls and basement rim joist spray foamed. $5000 later, I haven't really seen much improvement if any. Retrofoam is comming back out to do a thermal image of my walls. At this point, I don't know if the geo is working right or if the foam was installed poorly. I've done a lot of Google research and have talked to a few knowlegeble people, but everything seems right. My loop is incomming at 34F and outgoing at 31F. Both Geo's are sending water to the air handlers at 120F. The main floor air handler air temp just in front of coil is 65F and 84F just after the coil. Air temp at the register is 80F. The upstairs air handler has water coming in at 100F, so a 25F drop from the geo to upstairs. (I'm going to have my wall foamed between the studs that the lines are running in to help insulate them. This is an interior wall. The upstairs air handler air temp just in front of the coil is 69F and 81F just after the coil. Air temp at register is 81F. Everything seems right, but I'm not sure what the vent air temperature should be. I wasn't sure if my geo should be slowing the desuper heater usage down if the house was calling for heat too much. I'm also not sure if the system was sized right.