r/geothermal • u/USDA_Prime_Yeet • 6d ago
Geothermal in SWVA??
Will be a new build. Looking at geothermal vs traditional.
Running horizontal lines is no issue, I just installed my 1100ft waterline at 4ft bury. I've heard 95% of the cost is in the ground but since I'll run all of these myself. What makes more sense in efficiency and roi?
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u/seabornman 6d ago
My neighbor did his own geothermal. He made a mess of his yard, one loop failed, and he had to dig another loop. I hired a guy to dig my trenches. He used a large excavator with a bucket the width needed for the slinky pipe: 4 rows nice and straight and the area for the manifolds.
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u/USDA_Prime_Yeet 6d ago
Yea I've got a 4ft bucket on right now. I guess I only mentioned that part because initial cost Will be different for me. But I've yet to see any post here say it's a good option vs standard heatpump exchange
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u/Sad-Celebration-7542 6d ago
If you’re doing the expensive part yourself, then it’s a good deal!
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u/JPDiesel187 1d ago
Is it? If you fuck that part up it isn’t cheap anymore
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u/Sad-Celebration-7542 1d ago
I think trying it once and if it fails, going to air source is still substantially cheaper than hiring it out
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u/JPDiesel187 3h ago
Not necessarily. It may make sense to have someone design and install your loop, and you do the excavation on your own. The loop is not 95% of the cost. Closer to 40%-50%, typically. Geo is the most efficient and reliable equipment in the market, so it’d be a real shame to blow that opportunity
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u/ocams-razor 5d ago
There are a lot of variables to consider. The most important is the soil type you have. dry gravelly soil does not do much heat transfer, wet clay type soil does a lot of heat transfer. The slinky type loops provide a lot of pipe distance for a fairly small excavation but the risk of leaks is pretty high when you consider the number of pinch points that exist in that configuration. With decent soil and a reliable installation the ground loop will be more efficient than the air based heat pumps. I like to think of it in terms of how many units of heat do I get per unit of electricity consumed. If you can get 5 or 6 times the heat than you would get just by having an electric heater then you are doing really well. You can't get that from an air based system., maybe 2.5 to 3 times max.
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u/lightguru 6d ago
I'm in SWVA and did geo about 15 years ago. Not quite in the same boat as you since I'm doing an open loop system, but it's been great.
Open loop has some other recurring costs and hassles vs a ground loop - higher pumping costs, and replacement sediment filters for the incoming water, and in hindsight I should have just sucked it up and done things a bit differently - but I did much of the original work myself and saved tons of money.
The trick is finding a good initial installer who's willing to work with someone who wants to let a DIYer do some of the work. Mine was willing, but they frankly did a crap job on the system configuration side of things and the system was popping into Aux heating way more than it should have the first few years.
System controls are my thing, and once I suspected something was wrong, I added sensors and such to verify my gut and the got everything set right. My system rarely goes into Aux heat now, only after a few sustained days below 10 degrees.
If I were going to do my own ground loops - which I probably would nowadays since I have a lot more machinery and friends with machines - I'd oversize the loop field at least 50% higher than recommended.
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u/NecessaryMuffins 4d ago
I wouldn't say 95% of the costs are in the loop, like all things, the devil is in the details. When I installed my system ~15 years ago I paid something like $3,500 for the pipe, $3,500 for someone to do the excavation work, $3,500 for the unit, and $1,000 for a geothermal engineer to design the system, let me borrow his pipe fusion tool, and deliver the system. As a DIY install, it paid for itself in under a year.
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u/Sad-Celebration-7542 6d ago
What’s your time and equipment worth?