Videre non videri
Join Date: Sep 2004
Location: Gothenburg, Sweden
Bikes: 1 road bike (simple, light), 1 TT bike (could be more aero, could be lighter), 1 all-weather commuter and winter bike, 1 Monark 828E ergometer indoor bike
I can just give you an example from my parents' house.
It's located in a climate where the temperature generally drops below 15°C (60°F) in October and gets back up above 15°C again in May. Typical winter temps are between -10°C (15°F) on a relatively cold night up to 10°C (50°F) on a warm day. Average daily temps between -5 and 5°C (25-40°F).
Before the geothermal unit was installed, the yearly electricity (the house was heated by electricity alone - with a fireplace for backup on really cold winter days) usage was 29 000 kWh on average. After the installation, the past two years have seen an average usage of 13 500 kWh. Around half of those 13 500 are non-heating related (lights, TV, computers, appliances and so on...). So, in effect, the electricity used for heating went from around 22 000 kWh to 7000 kWh. Given that the situation is relatively similar where you live, you could possibly save 1/2 to 2/3 on your gas bill!