I just finished having my wells dug, 4 @ 150′, for my geo-thermal heat system.
I think it’s a 4 ton unit based on the 2900 sq. ft. house I’m building for my family. I was just curious to hear what anyone thinks who has a geo heat system. Do you like it, cost, efficent?
Thanks
Roy
Upgrading the footings and columns that support a girder beam is an opportunity to level out the floor above.
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I have had mine in for five years and have been very happy with it. I have two units that share one loop. I am heating and cooling approx my home and shop with it. The shop is 1250 sq ft, 10 ft walls and 16ft vaulted ceiling(2.5 ton system). The house is approx 3200 sq ft. 9ft ceiling on main floor and 8 ft on second(5 ton system). Utility bills average approx 200/mo. Keep the house and shop around 76-77 in the summer. (house is total electric)Atlanta heat can be brutal and the highest bill I have had in the summer is about 310. I have freinds heating and cooling half that space for about the same amount.
Edited 8/14/2002 4:16:54 PM ET by Tom
Mine's been running for 2 years now and I love it because: 1) I don't have to do anything to it; 2) it's quiet; and 3) it's efficient. We've been over 90 practically every day this summer, so it's running about 75% of the time. 4 Ton unit (800' of tube) cooling over 6000 sf. Keeping the place be/t 75 and 78. All elec. Biggest elec bill was less than $200. So far it's a no muss, no fuss system. Knock on wood.
I have the same set-up..........4 ton / 2700 sf and it's undersized.
Anything under 17 degrees and we freeze. We added a wood fired insert with a remote blower and radiant floors on in the kitchen / living area. Happier.
As far as AC....excellent, very happy. Cool to cold weather, down to 30 degrees and it's wonderful. The point is to engineer the system to fit the space. If I had to do it over again, I'd still do geo-thermal.............I'd just spend more time and money on the sizing and engineering.
if i may ask what was the bottom line of your system, and how long do you think it'll take to re-coup extra $$$$. i'm on the fence myself and any more info i would appreciate.. thanks bear
Cost was $7,000.00...........7 years ago...........with an all electric or propane as the only options, I figure I've already recouped.
A note on those additional options........get the storage hooked to the hot water heater. During AC days, the heat drawn from the system heats the water for these 7 people who all love to linger in the shower.......
I figure my highest energy cost is spent on heating delightfully cool well water. Gotta figure a simple, solar "preheater" to warm things up before it hits those electrodes.
I had a 5 ton Water Furnace system installed in my father in laws house when I built it 10 years ago. 2700 sq. ft. ranch with a 2500 sq. ft. walk out, all conditioned space. Average all electric utility bill for the ten years is about $ 96.00/ month. Electric rates here are a little over 4 cents a KWH (lowest in the country,I think), your mileage may vary.
Over all the system has performed very well. Much of that depents on the installation contractor and the manufacture of the unit. I believe they have had two service calls in ten years for factory warrentied issues.
They are about 25 miles out of Louisville KY, and our weather here has been like Cloud's much of the summer. If you haven't already had the system design, I would recommend taking your prints to certified system design engineer. You want a total system design that includes duct sizes, placement, supply cfm and return air reguirements for every space in the house. Most installation contractors around here use generic calculation to arrive at unit sizes and the actual duct work is a total joke. I have seen a lot of geothermal systems that don't live up to thier billings because of poor system design, not bad equipment.
FIL paid about 10K for his system in 92.
Tim should jump in here about now and fill in the blanks on system design.
Dave
Actually after checking my proposal it is for a 3.5 ton unit, Command-aire #GSUFO421AD1L020 with a seer rating of 14.2.......Digital therostat.........duct work ect...........piping...........15 kw strip heater = $8900
Options > Desuper heater package with 30 gal. storage tank connected to customer's water heater = $600
Higher effiency equipment 16.1 seer = $400
Zonning package to include bypass damper, zoning dampers, three zone digital command center, temperature sensors, and three thermostats = $1900
The wells were furnished by us at $ 3.25 per foot for 600 feet
My contractor said by zoning it off we could use a smaller unit and he did sent it out to a engineer to size it.
So there is all the info...........Tell me any other thoughts you all might have
Thanks
Roy
>The wells were furnished by us at $ 3.25 per foot for 600 feet
Lucky SOB. Here it's 7 or 7.50. That makes a difference, huh?
I have to agree with Mark. get the desuper heat option. When the system is operating you get hot water at no additional cost. The utility company I work for installed seperate meters on a geothermal system, electric hot water heater and a "house meter". Durring the a/c season the meter for the hot water would not have gone over thier minimum charge kwh if it had been the only meter they were reading each month.
Check on the pay back time for the higher SER equipment. If you will save the additional $400 in five years or less, go ahead and ivest it now.
Zoning is good, but be carefull with the "allows for ussing a smaller unit". What happens if all zones are calling for heat or cooling? will the system be of adequate size if that occurs? An undersized unit may run excessively, and an over sized unit could short cycle.
Sounds like you have a good contractor though, and you have studied the system, so you know what he is talking about. I beleive you will be pleased with geothermal.
One caution, geothermal is a heat pump, don't expect any more than 95 to 100 degree air durring the heating season. Senseable heat at these temperatures feels cool to most people, so I hear complaints that these systems are not as comfortable as gas systems. Supply and return air loactions are important, to avoid cold (95- 100 degree) air drafts across the rooms.
Lets us know how you like it after a few months of operation.
Dave
>One caution, geothermal is a heat pump, don't expect any more than 95 to 100 degree air durring the heating season.
Makes a good case for hydronics, no?
Yes, wasn't there a thread about using geothermal as the source for hydronic heat some time ago. I'll have to search for that one.
To All:
I didn't mention I live in central PA, 25 miles east of State College. Winters are nothing since I moved here in 1990 from Vermont ( a little different there ). I'm just finishing my rafters this weekend (90 degrees and humid) can't wait, so it will be a while until my system is installed but I will get back and post my feelings. I'm also going to look into a bigger unit to be safe. I talked to a man last night who told me this (geo-thermal) started at Oklahoma University and there is all the info there. I haven't looked yet but intend to. Any and all thoughts are welcome.
Thanks
Roy
Here is a link to the geothermal information site.
http://www.eren.doe.gov/consumerinfo/refbriefs/t354.html
I was probably in on that one, be/c that's my system composition. The moderate temps it produces are just fine with a hydronic system. I prefer the kinder, gentler heating to the fast and furious. <G>
Here's a question for you, be/c I haven't been able to raise my local expert. Do you have any install estimates for the pipe? What would you expect the tubing to cost for a 500 ft well, for example. A client mentioned a number he was told that sounded nothing like what I recalled, and I wanna get his expectations in line before he dismisses it based on bad info.
I just paid a $1.20 a foot for the looped pipe installed and about .60 per foot for screenings. I was able to use the cruched limestone from drilling to fill in a lot of it. Drilled 4 @ 150'
Roy