Before and After Bills

It seems geothermal is used more often in new construction, or at least I was having trouble finding as many people who retrofitted. Are there examples on this site of energy bills/usage before and after on retrofit systems?

 

You can look right down at this thread below:

http://www.geoexchange.org/forum/threads/new-system-in-central-new-york.4982/

I uploaded a graph of our electric usage which shows before and after values. I mentioned in the post when the geo system was put in, so you can see the impact it has had.

Since that post, I can say with a couple more years under our belt, that our 12 month average with the geo system in, is around 1050-1100 kwh per month. That compares to 811 kwh / month in the 2 years prior to installing the geo system.

Keep in mind, that now that the geo system is in, there is no wood or heating oil use. Oil heat at $4 / gal prices would have cost us more than 3 k annually. As best I can tell from my increase in electric use, since the geo went in, is that it runs me about $300-$400 per year to heat my place. Even this year, with the colder winter, and electricity price increases, I'll be under $500. Do take your local electric prices into account, as some areas have had huge increases in price this year. We have not.

 

Your chart is nice, but I was of course hoping to find a more apples-apples comparison. In your case, you went from "free" wood to a modest increase in electricity, which is great. But would be nice to find someone who changed nothing but the furnace/ac, or went from gas to electric geo...but nice charts like yours are hard to find, it seems.

 

No wood is "free", even the stuff you cut off your own property I paid dearly for every piece I cut and hauled. The comparison is pretty easy, though. When we heated with wood we generally used about 6.5 full cords and 20-50 gal of oil. So at $200 per cord and $4 per gal oil ( if you bought it all retail) that's around $1380 / year. The years we heated with oil only, we used 750-800 gal, so $3000-$3200 at $4 / gal. We replaced a 20 year old forced air oil furnace with the geo system.

FWIW, the guy who put in our geo system did a heat loss analysis of the house. He estimated heating cost to be about $2700 at $3.45 / gal oil, at the time. He also estimated the geo heating cost to be $593 at $0.11 / kwh electricity. His calculations were pretty close to reality.

 

I went from a 20(?) year old oil furnace/window AC units to a 4 ton Geo system.
Estimated oil cost are based on HDD and 5 years worth of oil usage from prior years.

 

These are great, thanks!

 

Here is an email (testimonial) from one of my customers who keeps nicely track of his energy use. . While an n=1 is not data, it might help to give you an idea.

"Here are my "Hard Numbers" up to this point. The Electric Summary sheet can be a little confusing at first to look at but basically I give my 2011 and 2012 electricity usage on the left. The columns on the right are my 2013 Electric usage in KWh the the cost. Then how many KWh of solar and how many KW of Geo so that gives me then the 13 Total column is my total electricity usage since my solar panels sell back to the grid and reverse my meter so that is total solar production plus my billed usage. Then I have the total different of KWh usage vs 2012 when I did not have the geo. So that number ideally represents the true electricity usage of geo thermal over my propane usage.
So looking at this sheet it costs me $657.67 to run the Geo for heat this winter up to yesterday (because that is when my meter reading is from). Because of Solar I have saved $175.63 to make the overall system even more economical. But the $538.33 is really how much more the geo is costing me in electric over the electric usage of my old propane system and space heaters that we ran in our daughters room which we do not run anymore.
So then if you look at my propane usage sheet propane cost me $1,772 last year and that was keeping the heat at 62 instead of 68 and it was a very mild winter last year. But just comparing the plain cost of the geo I am paying about 30% of the cost of propane.
Hopefully that makes sense. I will send you the sheets again when we complete the year if you want then we should hopefully see the saving on the AC side as well.

Thanks,"


So he is at 30% of the costs (vs propane) despite a lesser degree days the year before and has higher comfort (68F versus 62F with propane).
The system is WEL 601.
http://welserver.com/WEL0601/

 

Attached is a photo of a new home that drywall was completed and than we turned on the system mid feb. The photo is energy usage of March, not bad for a 2,600 house that had plenty of doors opening to bring in tools, kitchen equipment, etc...and it was COLD, left it at 68F and cost about $100.00

 

Would like to compare numbers with a fellow 7 series owner.
In Ohio on Wed 26th in 2000 sq ft home at around 35 degrees
avg kwh 1.3
total kwh 30
run time 23 h
thermostat 71
Does this seem high? What were your numbers? (I know there are a lot of variables)
Thanks, Matt

 

http://welserver.com/WEL0713/

3 ton 7 series new built 2600 sqf Buffalo, NY

 

4 ton series 5 3500 sqft Cincinnati, OH
Avg outside temp: 35 on 12/3/14
avg kwh 3.5 (Using first stage of compressor)
total kwh 44.5
run time 12.9 hours (idle 11.1 hours)
thermostat 72

 

These numbers are moving targets. No two pigs are the same height.

 

ACES installed my system a month ago, once winter is over, I will post last year's (oil only) vs this years (oil until early Nov, Geo since).
Currently, with my 7 series 5 ton, I am calculating ~80% cost savings (I have good data from last year, so I know my average oil consumption per HDD, and I am calculating what my theoretically daily oil consumption would have been and comparing it to the thermostat's electricity usage. when running in Stage 1 of 12 or 2 of 12, I am a little below 90% savings, when running in Stage 4 of 12 or 5 of 12 I am closer to 80%, and I am sure as it gets colder and I start going into higher stages my savings will go down a bit.
I haven't yet received an electricity bill with 30 days of geothermal, but my last bill included 10 days (in which several days stayed below freezing) and I spent ~$40 more in electricity than the previous month. I expect my January/February bill to be $200-$400 higher than last year, but I spent ~$1000 each month (For Jan/Feb) in oil last year, so even a $400 monthly cost would be a substantial savings.
When I get some real data, I will post it.

 

I love good news.

 

Was 80% the suggested savings?

 

I think you were talking to me?
Purely looking at the heating aspect of it ACES was suggesting a ~75% savings for the entire season, As stated, at lower stages of the 7 series I am in the high 80% range, when the machine is around stage 4/5 of 12, I am just above 80%, I have yet to see it at stage 12 (system is designed for down to 2F (at a late winter loop temp) for stage 12. It hasn't gotten that cold yet. So until I see what full capacity is like, I will not be able to see what my savings would go down to (for those specific days).
My assumption is that over the season the 75% should be close, or I might even do a bit better (here is hoping).
Also, I have not yet started to calculate if and what the desuperheater is saving me, as the best I will be able to do for that is take the waterfurnace thermostat energy estimate and compare the kWH number the electricity from last year, and see if there is an undercut (aka see if my other electricity consumption is down because I am heating less how water).

Regardless, I am thrilled that I don't have to worry about purchasing oil anymore, and my house is more comfortable, but I probably should be spitting out number with only 35 days of total run time.

 

And we have converted another one to a geojunky....When are we going to put that 4'x8' billboard in your front yard and get you a commission check for each sale you make for us???

 

The small sign is still there, and only occasionally covered with snow.

 

Congrats AJ (aka ACES) for being one of the guys who knows how to make those systems efficient. Glad to have you in the neighborhood!

 

Hey Doc - Thanks. Small world and weird that I replied to this post last night and I personally found my self at "SeekAdvice's" house today while he was at work. I was able to turn down the variable speed minimum % speed a bit more to save him even more money!!