DIY Digging trenches for Geothermal

[edgarrian]

I dug the trenches for my gramps geo thermal and the guys where there to do it as i dug. As i have already mentioned with your trench depth being 6 foot deep you will need to fold the sides back especially if the trench is taking in water. Make **** sure you don't let the trench cave in on one of those guys.

 

[ovrszd]

Huge difference between a 4' trench and a 6' trench!!!

 

[edgarrian]

I have heard of guys getting killed in a 4 ft trench. Guy is by himself, digs the trench. Gets out to lay his pipe. Bends over and trench caves in. It really doesn't take much. 6 ft trench is generally going to be over a guys a head. As i said a few times in this thread you need to be mindful of the trench taking in water. If trench starts falling in then you need to bail that section even more. What type of soil do you have. Is it sandy, sandy with clay, or clay.

Huge difference between a 4' trench and a 6' trench!!!

 

[Hickorypond]

I dug 6' for the lines to my pond with my 1720. Most installers put a manifold in the ground this is where you will have leaks and can have a cave in, don't get in the trench. Run complete loops inside near your pump and valve them. it's way easier to fix if you have a leak later. I put 2 spare loops in just in case. Check out B&D flow centers for self purging pumps.I put a 2 stage unit in and don't have backup heat, I'm good to 0 degrees and cooling is sized right. Do a manual J for your demand load,you can find an online calculator. I have about $6000 in mine for everything. On another note I baled some late hay with my 1720 this week using a small round baler.

 

[Gofast]

We have red clay here it is not real wet. The clay is very hard and it makes nice stable sides in the trench.
I will run all loops under or through the footers and the manifold will be in the crawl space.
I did not know 1720 had enough power to run a round hay bailer what king of bailer was it?

 

[LD1]

I was wondering if others did this. If a loop did not hold pressure and you had it covered up it would be a huge deal.
I don’t have great luck I think I will do this as well.

We have red clay here it is not real wet. The clay is very hard and it makes nice stable sides in the trench.
I will run all loops under or through the footers and the manifold will be in the crawl space.
I did not know 1720 had enough power to run a round hay bailer what king of bailer was it?

Pressure testing prior to backfill is great....BUT....the greatest risk of developing a leak is from damage during backfill. Dropping a 20# rock with a sharp edge down on the pipe that you didnt see in the spoil pile.

So testing AFTER is also a must.

I have ZERO connections or welds in the ground. For my 600' loops (I actually used 800') continuous lengths of pipe, all stubbed into the house to a manifold. ALL connections are in the house....thus greatly reducing the odds of ever developing a leak outside and having to dig it up again.

 

[Diggin It]

Mine says it will dig 77 inches or so, but I doubt I'd ever try to dig trenches that deep, that wide and that long. Geo might be nice, but I also doubt I'd ever see the return on investment since I'm sure it's rather expensive.

Thinking another couple of seconds tells me I don't even have room to do it given the layout and terrain of my property and the presence of the utility water line in my front yard.

 

[Hickorypond]

I imported a Runshine 850 mini baler from Alibaba and a rotary rake also.There are a couple of US sites selling them for $7000, I paid $1800 plus import fees. I bought my property to keep busy, it would never pencil out. I would borrow a backhoe for your ground loops.Clay is good ,dry is going to need more loop length. I used 800' loops also. Like LD1 said the problem is watching out for rocks when backfilling.

 

[LD1]

Mine says it will dig 77 inches or so, but I doubt I'd ever try to dig trenches that deep, that wide and that long. Geo might be nice, but I also doubt I'd ever see the return on investment since I'm sure it's rather expensive.

Thinking another couple of seconds tells me I don't even have room to do it given the layout and terrain of my property and the presence of the utility water line in my front yard.

Geo isnt for everyone. But if you are capable of doing some of the work yourself....ROI is no different (or even better) than a conventional Air to air system.

So if you are building a new house and comparing air-to-air vs geo......the numbers make more sense.

If you have a perfectly working conventional HVAC system.....it dont make much sense to spend thousands of dollars to switch to geo for only a few hundred a year savings.

Now if your conventional system fails, and you are staring at a $5k or a $10k replacement of the system or components....its time to re-evaluate.

And for not having the land....not a deal breaker. They can do "vertical" loops. So instead of a 300' trench to do an out-and-back run of 600' of pipe....they just drill a well 300' down into the ground. Expensive....yes. But so is digging the trenches if you arent capable of doing it yourself either. But it does give the option of GEO to people who's lot size is measured in Sqft rather than acres

 

[Gofast]

Geothermal fed tax credit is 30% and our state SC is 25% that is 55% off the cost so at least this year it can compete with a heat pump install.
About 5 years ago I did a DIY solar install 12.5 KW covers our home and driving our Chevy Volt 19K electric miles a year.
In the last 5 years we have driven 90K electric miles on solar power.

@Hickorypond that hay baler is very cool.
I am going to put in 2400 pipe for a 3 ton system that works out to 800' a ton.

 

[quicksandfarmer]

I imported a Runshine 850 mini baler from Alibaba and a rotary rake also.There are a couple of US sites selling them for $7000, I paid $1800 plus import fees. I bought my property to keep busy, it would never pencil out. I would borrow a backhoe for your ground loops.Clay is good ,dry is going to need more loop length. I used 800' loops also. Like LD1 said the problem is watching out for rocks when backfilling.

I'm really interested in the baler and rake but don't want to hijack the thread. Can you start a new thread in either Haying or Chinese Tractors describing them?

Thanks.

 

[Gofast]

Feel free to hijack the baler and rake on a subcompact is very interesting.

 

[LD1]

Geothermal fed tax credit is 30% and our state SC is 25% that is 55% off the cost so at least this year it can compete with a heat pump install.
About 5 years ago I did a DIY solar install 12.5 KW covers our home and driving our Chevy Volt 19K electric miles a year.
In the last 5 years we have driven 90K electric miles on solar power.

@Hickorypond that hay baler is very cool.
I am going to put in 2400 pipe for a 3 ton system that works out to 800' a ton.

I remain convinced (and yet to hear an argument otherwise) that the HVAC contractors are the ONLY ones who get any benefit at all from the 30% fed credit.

In my case, I was in a house with baseboard only heat, no forced air. So I needed all new just as a new built house would need.

Comparing a 4-ton conventional air to air unit to a 4-ton geo unit. With the air to air being a turnkey install....and the geo unit with me doing all the loop and exterior work and giving the contractors the lines through the wall to connect to.

I was utterly dumbfounded when the quotes for conventional were all in the $12k range and all the geo quotes in the $18k range.

Lets break it down to basics....
Ductwork is a big expense...but there is NO difference in material cost or labor cost. The ductwork dont care what type of furnace its hooked to.

Im buying ground loops and doing excavation so that is irrelevant.

Cost of the furnace package itself....surprisingly similar. $5k-$6k for a 2-stage geo unit...add another $800 or so for the pump center. Same 4-ton 2-stage air to air....pretty much same costs. But more labor to install actually, because you have an indoor and outdoor unit to set, have to supply power to both....and have to have a license to do the refrigeration work (not required on geo).

So Im scratching my head as to how in the world the Geo cost $6000 more :EEK:

I questioned the HVAC guys that gave quotes....ALL THREE had the EXACT SAME response.

"well it isnt really $6k more because you get a 30% credit...so its only a few hundred more."

Makes sense right. Who would spend $12k on a conventional system when $12.6k gets you geo right:thumbsup:

Yea....you aint fooling me. Did my own install, hired ductwork done only, was under $10k out of pocket. THEN I got to collect my 30%. And that even included a $1000 buffer tank for the desuperheater.

So to summarize.....I think the ONLY thing pushing the geo so astronomically expensive is because of the shyster contractors that do so, just because they can. Since I did the excavation and loops myself.....geo SHOULD have been cheaper AFTER the 30% by a good ways. But that makes no sense right....

When the tax credits and rebates go away, I look for geo cost to consumer to stay about the same. But it will put a BIG damper on the profit margins for the contractors.

 

[Gofast]

I 100% agree with you and just told someone exactly what you said over thanksgiving.
When I did solar it was the exact same story, I got a quote for 4.6 KW system and I did a DIY install for 12.5 kw system cheaper.
Then I got the tax credit on top of that 30% fed and 25% state tax credit. It paid for itself 4 1/2 years.

The quote for GEO was 33K. The system i am buying and everything to install it is 9.5K that is before the tax credit. I will need to add digging equipment rental and i will sub out connecting it to the my duct work. The old system removal and the duct work I was quoted $600.

 

[Diggin It]

My LP Forced Air furnace cost me $700 brand new in the box. I did all the ductwork myself while doing the other renovations like drywall over block, new windows, etc. I wasn't doing central A/C so no outside work, copper coils, duct insulation, etc.

LP costs me less than $300 year and that includes cook stove/oven. Power for the fan/blower is my only other cost at maybe $10-15/mo over my normal usage.

I like the idea of GEO not needing LP, but I don't see even close to ROI in my lifetime. Same with solar, but the big difference there is when the lines go down for a week due to a storm.

 

[LD1]

My LP Forced Air furnace cost me $700 brand new in the box. I did all the ductwork myself while doing the other renovations like drywall over block, new windows, etc. I wasn't doing central A/C so no outside work, copper coils, duct insulation, etc.

LP costs me less than $300 year and that includes cook stove/oven. Power for the fan/blower is my only other cost at maybe $10-15/mo over my normal usage.

I like the idea of GEO not needing LP, but I don't see even close to ROI in my lifetime. Same with solar, but the big difference there is when the lines go down for a week due to a storm.

No way to heat a house, and cook on $300 of LP here unless you live in a 500 sqft home with r-30 in the walls, and eat cereal year round

 

[ovrszd]

No way to heat a house, and cook on $300 of LP here unless you live in a 500 sqft home with r-30 in the walls, and eat cereal year round

Yeah me neither. Not sure where he's located. I asked one time and got "why, you want to come and visit?"

 

[hawkeye08]

We wanted geothermal when we built back in '93, but did not have budget. We heated with wood pellets (3 tons or so per year, at ~$110/ton) until we switched to propane for heating. We also plumbed for and added a 6 burner cooktop, so we heat and cook with propane, about 400 gallons per year, price varies of course.

 

[Diggin It]

^^ Yeah, I probably should have said 300 gallons, but since I get about 400 every 18 months, it averages out to somewhere around $300/year over the last 5 years. This time it was $1.699/g, but I've had it closer to a dollar not too long ago.

 

[Hickorypond]

I'll take a picture of the rake & baler tomorrow, may start a new thread under Massey. Don't want to upset the real hay guys.

I work at a large HVAC R&D facility, I bought a Miami Heat Pump for 1/3 of their unit price and mine is built better. Dealer mark-up on unit is 2x minimum. And every time the government subsidizes the price goes up that amount. I paid $6000 for everything, including 2 stage unit,desuperheater,pumps ,pipe,buffer tank and a new water heater plus got 30% tax credit and $1200 from electric utility so $3000,same set up is $30,000 in my area. I did manual J myself so I know calculations are right.