Geothermal vs Oil / Propane

[babzog]

Hey folks,

Living nr Ottawa, Ontario, Canada. It gets mighty cold here in the winter.. heating is generally on from October through March. 2400sqft house was built in 1991 to R2000 standards. Geothermal (Waterfurnace Premier AT) was installed at that time. Last April, the compressor and coaxial heat exchanger were replaced.

The Ontario government is hiking hydro rates to unprecedented levels to pay for so-called "green" technology for power generation. Whether or not you agree, the bottom line is, with hydro rates set to double in the near future, is geothermal still worth it from a purely economic point of view? My bills right now are $350/month and I have propane for hot water, the kitchen range and the dryer. I have a woodstove in the basement which I try to use 24x7 during the heating season. My lights are nearly all CFL (except for those lights on dimmers and external lights) and I try to turn them off when not in use. Electronics are all modern and "sleep" when not in use. Short of cutting power to electronics (marginal savings), I think I've done what I can to minimize hydro usage. The main cost is running the geothermal unit.

I've been considering replacing it with an oil furnace (also considering propane as I've got the tank and infrastructure installed already). Ideally, I'd like to have a combo wood/fuel appliance, but I've been told that gas/wood units are not allowed in Ontario (dunno if that's actually true?) which might limit me to wood/oil. There are also lots of cheap furnace/tank combos on kijiji right now as many folks are switching to nat. gas (will never be available in my area).

So, my question comes down to this? Without considering the social and environmental impacts (those are personal considerations and outside of the context of this post), what is going to be a more cost-efficient solution for the next 20 years? I know geothermal is considered 100% efficient, but if it still costs more to run it, I'm no further ahead (and actually behind).

[cturman]

Here is a spreadsheet that will allow you to enter your energy costs and compare.

http://www.eia.doe.gov/neic/experts/heatcalc.xls

[jerryd_2008]

Hey folks,

Living nr Ottawa, Ontario, Canada. It gets mighty cold here in the winter.. heating is generally on from October through March. 2400sqft house was built in 1991 to R2000 standards. Geothermal (Waterfurnace Premier AT) was installed at that time. Last April, the compressor and coaxial heat exchanger were replaced.

The Ontario government is hiking hydro rates to unprecedented levels to pay for so-called "green" technology for power generation. Whether or not you agree, the bottom line is, with hydro rates set to double in the near future, is geothermal still worth it from a purely economic point of view? My bills right now are $350/month and I have propane for hot water, the kitchen range and the dryer. I have a woodstove in the basement which I try to use 24x7 during the heating season. My lights are nearly all CFL (except for those lights on dimmers and external lights) and I try to turn them off when not in use. Electronics are all modern and "sleep" when not in use. Short of cutting power to electronics (marginal savings), I think I've done what I can to minimize hydro usage. The main cost is running the geothermal unit. ...

Wow! Is that total energy cost or just for electric and is that just this month or the monthly average? And is that when you are using the wood stove also? Have you looked into using the geo to heat water? May not be great that far north though.

So, my question comes down to this? Without considering the social and environmental impacts (those are personal considerations and outside of the context of this post), what is going to be a more cost-efficient solution for the next 20 years? I know geothermal is considered 100% efficient, but if it still costs more to run it, I'm no further ahead (and actually behind).

No, I think that geothermal is more like 400-500% efficient. Resistance heat is 100% efficient.

[can2man]

Geo systems are 400% efficient. In ontario we are looking rising electricity costs - most likely it will be 3% a year for ten years or so - basically inflation. All the other fuels will rise accordingly ('cept maybe wood) so if you are ahead now of the other fuels and I think you are - geo will still be most cost effective system in ten years.

[whatsthat]

A few things to keep in mind.

1) Your 20 year old Premier AT system has a rated COP of between 3.3 and 3.6. In efficiency terms lets say 350%. Correct me if I'm wrong but it is also a single stage unit. If you need to replace the system you'd be looking at heat-pumps that are 2-stage with COPs in the 4.5 range. Better comfort and efficiency.

2) Look at the at the oil and propane prices over the past 10 to 15 years. With the exception of the past couple of recession years, those prices have been increasing at a rate of close to 10% annually. Even if Ontario's electricity rate increases by 40% over the next 10 years, that is still only 3% per year (less than oil or propane and as can2 mentioned it's the same as inflation). You're still ahead by keeping geo.

A couple questions for you: do you have a closed loop, or are you using well water? Do you have a smart meter installed yet? The 40% expected increase assumes the average homeowner on Time-Of-Use billing. Time-Of-Use billing may actually lower geothermal costs since the geo unit runs longer at night (when it's colder) and that is the same time electricity rates are at their lowest.

[jerryd_2008]

And if you replace the older geo unit with a more efficient one you already have the wells which are a big part of the initial cost.

[Primary Loop]

The way I see it is wood-oil combo units are great if you have a means to good wood. There are lots of oil companys out there that you can bargain with for prices. Propane furnaces are now running in the 95-98 efficiency
range. Again lots of lp prices to chose from. Hydro rate ??? not to many hydro companys to chose from is there. Alot of the Geo units now are 2 stage running flat out alot of the time from what i have seen.

[skeller]

Lp prices would have to be .22cents a gallon to be competitive with geo systems. If they are installed proper, loops too, you can get up to a cop of 5.1. The ground temp is at least a constant 55 degree at 8 feet deep. They only produce temps up to 100 degrees but that is still a hot temp.

[Southern Mech]

I would do a wood, and oil combo boiler to an air coil. That far north you need something that will crank out a goot delta t. just my opinion.

[youarerelevant]

2 stage Geo all the way! A IGSHPA instructor says he has a 1500sq ft on a basement rambler in mid west where temps for 3 weeks at a time are below 0 f. He has a separate electric meter on his geo system and it runs him about $600 a year. My .02

[chloeourdog]

The spreadsheet above was very good at helping me to refine my decisions. I added a section that takes into account the initial cost of each type of system and the amount of years it would take to recover that cost in energy savings. In MD electricity is expensive and gas is cheap (today ...)

[mstrblstr3]

I would do a wood, and oil combo boiler to an air coil. That far north you need something that will crank out a goot delta t. just my opinion.

Time is money and cutting wood takes time and lots of effort
Check with your insurance company, i get a big savings discount because having a Waterfurnace means that I have no combustion in my house. My fire risk is a lot lower than others and they like that

[tedkidd]

Cturman, thanks for the great calculator. Pellet stove co used to have a nice calc like that but they took it down, probably when pellets got expensive...

Yours is better anyhow...