Hi All, Looking into using geothermal for a new construction home we are building in lower Connecticut. Our current fuel option we are weighing against are propane and oil. A builder we had been talking with asked if we had given geothermal a thought and after some short research I see the most commom issues being excessive electric bills whether it's from the back up system or the heat pump drawing a lot of electricity. The house is about 3,000 sqft of finished space with another 1200 possible to finish in the basement that will have 9' ceilings. The only nuance is a two.story family room so I am not sure about how much of a chimney it will act as. Looking for any thoughts or inputs especially from those who have a system in a similar climate and most interested in wherher it keeps up on the cols days with out switching to electric heat.
Welcome. We have some systems streaming live performance data on our website, which might help with some of your questions. Buffalo NY weather might be similar to Connecticut. http://buffalogeothermalheating.com/sample_diagram.html A few which fit your house you describe. 1998 built, 3318 sqf, 5 tons http://welserver.com/WEL0663/ 1990 built, 2901 sqf, 4 tons http://welserver.com/WEL0601/ 1998 built, 3028 sqf, 3 tons http://welserver.com/WEL0478/ Your house will be more efficient, since it is a newer building code. Geo systems do not switch over to electric resistance, but they sometimes use it to supplement on extreme days. With the introduction of variable speed technology we now design with less and less supplement heat. Attached is the energy profile of a new built 3500 sqf house (plus 1800 sqf basement) about 20 miles north of Buffalo, and the last 10 months of energy use with a 5 ton Waterfurnace variable speed 7 series, with a 2 story living room. Hope this helps with some of your questions..... In my opinion a no brainer compared to oil or propane, but you can be the judge.
You are focused on energy conservation performance. Consider the building as a system. Use your new construction opportunity to go somewhat beyond mere code minimum energy details. Don't go Passive House crazy but shoot for a "pretty good house" with details 25 - 75% better than code minimum. Insist upon a proper Manual J (heating and cooling load) and that ducts / zoning conform to Manual D. Make sure the envelope, in addition to being well insulated, is substantially air tight. Install decent windows but don't go nuts. The best ton / Btuh of HVAC capacity is that which you don't need to buy, install, duct, hear and pay to run. In addition to the envelope and HVAC, pay attention to the other "energy centers" within the project: 3) Water heating 4) lighting 5) laundry 6) refrigeration wherever located 7) balance of kitchen 8) media gear
Doc offers very good advise. In regards to air sealing which he mentioned, make sure you blower door test before you sheet rock. If you want to make things really interesting reverse your blower door to pressurize the home and use a theatrical fogger inside. Do this on a day with little wind and walk around the outside of the home. You will quickly see any major leak locations.
