|12-16-14, 10:49 PM
Join Date: Aug 2014
Location: Saskatchewan, Canada
Thanked 16 Times in 12 Posts
Inefficient home or inefficient GSHP?
So I have a relatively new home (unfortunately built before I knew much of anything about building it for efficiency) and the electrical bills had always seemed high to me, about $325 a month on a farm rate of $.106 but it was cheaper than my old house so I didn't pay much attention... I started looking into it about a couple years ago then really looking into once a friend of mine claimed his farm cost him $200 a month average year round (natural gas heat, a/c, gas water heater) which bugged me since I had installed geothermal (installer claimed 13 year payback if I believe), had a new house, and a well insulated basement. I have made leaps and bounds in electrical usage since then but now that it's getting colder my heat still seems to run a lot and it's really not cold yet (ran around half the night last night at -7c and our winters are often -20c to -40c) so first i'll list the place's specs and the improvements I've made and then what I'm seeing now.
-home is 4 years old, 1800sq foot 2x6 RTM bungalow with vaulted ceiling in the center, spray foam insulated/sealed from basement top plate to house floor
-basement is an ICF walkout with 8" concrete walls and wooden floor
-Hvac is a climate master tranquility 27 heat pump with hot water and there is a 2 ton console geo unit in a 600sq foot workshop that gets used for heating only and only kept at around 12 deg c. My ground loop was at -3c at the very end of last winter which the installer said was better that many. There is separate loops for the home and garage units.
-after the geothermal preheat water tank there is a dual element electric water heater, 3000 watts per element
So I was previously averaging 3000 kWh a month, changes I made were:
-changed commonly used light bulbs to LEDs and others to CFLs (total wattage previously if I had all lights on would be 4250 watts, new lights would be 660 watts)
-shut off yard light (approximately 470 kWh a month!!)
-turned hot water heater down a bit
-built a hot water heat exchanger on our main shower
-insulated the hot water lines that I could access(probably 85%?) and put a switch on the circulating pump
-crawled into attic and added insulation where the builders were skimpy
-make an effort to shut unused appliances and lights off. Monitored appliances with a kill-a-watt and unplugged one old fridge that was usually close to empty
-installed an Ecobee thermostat. Really like this unit, gives detailed reports on usage and easy to setup and control. My heating is 2 stage plus aux electric resistance heat, I believe I saved a lot here as the standard thermostat would turn on the grid heater after a certain amount of runtime whereas now I turned it way back. Heat pump runs longer but back up stays off.
After these changes in May I was averaging 1000-1200 kWh a month till The last few cold months, now it's at 2000 kWh. So it's made a very large difference! But the heat really seems to be using a lot and it's going to get much colder. At my current usage after the cold winter I'll probably be around even with my friends cost and he has made no effort whatsoever. According to my ecobee my house isn't very efficient, I'll include a few screenshots in a second, but a poorly running heat pump system would also fool the thermostat in thinking so I would think? What do you guys think?
Last edited by mechanic; 12-16-14 at 11:13 PM..