Question: Geothermal Vertical Closed Loop

[steve2278]

I'm building a new home on my existing property and I've been researching a number of different heating/cooling options and I find geothermal to be particularly appealing. Unfortunately the installation cost appears to be quite high when factoring-in the cost of the pump, piping and excavation etc. However, I got some very encouraging news today from a an experienced well driller who gave me an estimate on drilling a new well, as my existing well is rather shallow and picks-up a lot of sediment.

He gave me a price for drilling a new well, and he said if he got the job (and since he would have his drill rig set-up on the property) he would drill 3 seperate holes 120' deep for the geothermal system at a cost of $500.00 per hole. Great price in my opinion! Unfortunately the well contractor does not install the geothermal piping and I guess my question is "does the piping have to be installed at the time the holes are drilled?"

I have not yet selected a contractor for the geothermal system and I don't know if I need to do so at this point?

Geothermal contractors have a very specialized niche' trade and these guys have the right to make a buck just like everyone else and I respect that. At the same time, I'm a guy who's trying to save some money where ever I can and I want to minimize my expenses as much as possible. I came across a number of geothermal heat pumps after researching retailers and I can purchase a 3-ton geothermal heat pump for about $3,500.00. That being said, I can have the holes for the vertical loop system drilled for about $1,500 and I can purchase a pump for about $3,500, that leaves the installation and HVAC work remaining and I'd like to hire a contractor do just that portion of work specifically. I'm not sure if they would be willing to?...but I hope I can find a couple guys who would be interested in working in this capacity.

The problem is that most contractors want to take-on the entire job, however, I'd prefer to purchase the unit and drill the holes for the loops myself to save on installation costs. I'm just not sure if most contractors would be willing to work in this capacity and I'm not sure at which point to involve them and to what degree?

Any advice on how I need to proceed from here would be greatly appreciated.
Thanks in advance!
Steve

[gator37]

If you are "not" asking a contractor to take the responsibility for system performance or warranty issues you should be able to get a contractor (or skilled labor) just to install the system per your instructions (and your design) . There are issues that you should review prior to starting, such as soil type for heat dissipation, well number and depth, piping material, piping layout (reverse return, etc) leak test of piping, physical installation of pipe (since the piping can come on a roll with no joints other than the U bend at the bottom of the well), grouting of the holes and grouting material (very important after the piping test is performed (and passed)), filling and air purge of the piping, is the circulating pump included in the purchase of the heat pump (?) big enough to overcome the friction loss due to elbows, fittings, valves and heat exchanger pressure drops, who is going to wire it (power and control).
If the system does not perform you cannot expect the contractor to take the responsibility of the system installation that was initiated per your design and/or directions.
Most of their profit is from the purchase and resale of equipment the rest is typically labor with a little MU. (They have to eat also.)
If you are sure that you can provide all the answers for your design, I would hire skilled labor to install the piping and HVAC unit per your instructions and hire a contractor to wire the unit and start it up.

[gdgraham]

I agree with gator regarding a contractors willingness to take on your job. Sounds like not much profit an lots of risk for the contractor. I don't think you mentioned where you are located?

Do you have enough land for a horizontal loop? We typically install one 600 foot roll of 3/4" pipe per ton of equipment. At a depth of 5-6 feet. Just a thought.

[Earth Fire Energy]

I agree with Gators comments. There are many factors that need to be accounted for to have a successful operating geothermal system. Soil thermal conductivity, fluid flow rates, depth of boreholes and number of boreholes are just a few.