Here you go: After all rebates (there were several) & tax credit, my geothermal system ended up costing about $13,500. It looks like I'm going to be saving about 6000 kWh per year. When using an air source heat pump, I averaged about 27.5k kWh per year, and using the geothermal heat pump I'm averaging about 21.5k. Keep in mind that I don't even have a complete year of geothermal data, but I'm basing my estimates on what I have. Based on the numbers above and an electric rate of $0.11 per kWh, I'm saving $660/yr compared to my previous system. The ROI on that is about 20.5 years. So, if you have a working system and you're considering switching over to geo, based on my #s I'd strongly recommend against it as a 20+ year ROI is horrible. The reason I went with geo was that my old system died and needed replacement. I received several estimates for an air source heat pump, and they were around $9000. For me, it was a choice between a geo system for $13500, and an air source for $9000. I can't do much of an estimate comparing these two since I have no idea what sort of performance I'd be getting with a new air source heat pump. A huge plus for the geo system for me was that my geo system came with a 10 year parts and labor warranty. No one came even close for the air source heat pumps. Its also really neat that I don't have a loud evaporator in my back yard, but the value of that is very subjective.

geo is best in a colder climate where the hp can be used year round vs a air to air hp that dropped the output and shuts down at low temps. In mild climates you need to crunch the math to see if it really works, and what the pay off will be. The numbers to include are extra financing (you still need to front the initial bill!), electric costs, maintaining it (typically more then a hp/furnace), etc. However in my area, installing a 2 ton geo system in my new home would be cheaper then a gas furnace after credits. The 2 ton (waterfurnace) price is around $20k with vertical wells and duct work. A Lennox HP and furnace backup is about 13k with the same as above. However with the assumed tax credit and also a 3650 credit from the local power company, it puts geo below the price of the air to air hp, just over 10k to be exact.

âÂÂGeez, how are they going to know that you'll have a heat pump or not?â In Montreal, where the OP is located, the cost of the gas line installation and rebates for Energy Star gas appliances is predicated on anticipated gas usage and NOT having a HP installed nor the âÂÂDualâ electrical rate which is ~4.4â/kWh at temperatures above -12ÃÂC/10.4ÃÂF (most of the year) and ~18.4â/kWh at temperatures below -12ÃÂC/10.4ÃÂF (a small portion of the year). The âÂÂregularâ non-dual rate for electricity is ~8â/kW year-round. This dual energy rate makes electricity VERY competitive with gas at temperatures above -12ÃÂC/10.4ÃÂF and still competitive even below. A geothermal HP with a modest COP of 4 will cost just 1.08â/kW of heat DELIVERED into the house - that VERY hard to beat! The same kW of heat delivered into the house with a 98% efficiency gas furnace in our region will cost about 8.6â/kW of heat delivered into the house. Geothermal wins hands down at all temperatures above -12ÃÂC/10.4ÃÂF. However, the electrical rate jumps to ~18.4â/kW once the temperature drops below -12ÃÂC/10.4ÃÂF. ThatâÂÂs still only ~4.6â/kW of heat delivered into the house at the same COP-4 with geothermal, still not bad and still better than gas. The rest of the electrical consumption remains at the very high rate of ~18.4â/kW for temperatures below -12ÃÂC/10.4ÃÂF. Keep in mind that with geothermal the backup gas comes on to assist the geothermal and they work in tandem till the T-stat is satisfied. That is usually for only a short period of time and then everything shuts off except the blower that is usually on low stage. Or the geothermal can be shut off all together below -12ÃÂC/10.4ÃÂF as the electrical utility expects and gas only is used for heating. BTW: The gas company monitors gas consumption and they WILL know if you have a HP. You can have gas and a HP but donâÂÂt try to take advantage of the rebates or incentives! If you do take the incentives, then youâÂÂre âÂÂinâ for about 5-years of gas no HP. SR

I assume you do not have access to natural gas. It would be the most cost effective option. I am not the geothermal expert, but I can tell you the installation costs vary greatly around the US. I suggest you also look at the Carrier Greenspeed heat pump. It is more expensive than the traditional heat pump but will still be significantly cheaper than a geothermal installation.