New here, just stumbled on this community. Geothermal is pretty foreign to us as we purchased a cottage that has one. We've owned this cottage for a few years now that we are not at very much through the winter. It has a geothermal Water Furnace and in October we had an Ecobee 3 Lite installed in the fall the same time we had a maintenance check done. We recently spent some time over Christmas up there and noticed during stage 1 and stage 2 only cold air would be blowing. Not sure if it was actually cooled air as a result of A/C running or just non-heated air been blown by the fan, but it definitely wasn't warm. Warm air would only come out once Aux heating is engaged. Just got our hydro bill and it was almost 50% higher than last year for the same period and examining the data a bit more carefully we can see that similar temperature days use significantly more electricity since the Ecobee was installed. The previous thermostat was a Honeywell. So guess it could be one of the following: 1. Ecobee is installed wrong 2. Ecobee is installed ok but settings are wrong. 3. Furnance has issue and timing with new Ecobee is just a coincidence I'm heading back up there this week and having the company that did the maintenance check back in to look at the system. We are in Ontario so we have had temperatures in the minus 10 and colder. Right now we are in a deep freeze with overnight lows in the minus 20's (Celsius). Any tests I can run to try and isolate what the root cause is? Should we have the Ecobee run stage 1 and stage 2 run much longer? I recall that previously with similar temperatures once the furnace would engage, warm air would come out immediately. What could the Honeywell thermostat settings have been in regards to the stages and aux heat? I realize don't have the exact furnace model number or a picture of the wiring so help from the forum may be limited but will get that to share here once I head back up there. Any other information that would be useful to share? Any guidance or advice would be much appreciated. Thanks.