Hello: I am considering installing a GHP in 4-5 years, and while this is a long way off, I will be installing a lockstone walkway next spring beside my house which also happens to be the only suitable place where the GHP piping could enter my basement. I would therefore like to install some ducts or pipes from the basement wall to about 4' past the lockstone into the lawn area so when we go ahead with a GHP in the future we don't have to rip up the lockstone again. These pipes or ducts would be capped at each end until needed and then we would run the actual loop piping through to get past the lock stone. The length needed to get from the basement wall to an area on the other side of the lockstone is about 20'. Complicating this a bit is the future choice between a regular horizontal loop or a DX system that I believe needs multiple runs back into the house. So, any suggestions on what I could install now to prepare for either type of system in the future? Options such as 2 large ducts, 4 smaller ducts, multiple pipes and what sizes they should be, are what I am looking for. Thanks Michael

You could go with two large HDPE pipes 1"1/2- 3". If you go water-source, use them for headers; If you go DX cut the ends and use them for conduit. Sizes and numbers of pipes are based on size of system, loopfield and the general region you live in. If you've already got blueprints and specs for the house, it might be a good idea to go ahead and get a manual J heat load calc done, to get an idea of how big your system and loopfield will have to be.

Since there are too many unknowns... Consider installing a 6" or 8" schedule 20 drain pipe and cap it off at both ends. You could even spray foam inside the end on the basement sidel. This solution allows you to install whatever pipe you need when the system is installed in the future. It will also give you access between the inside/outside for wire or whatever. Maybe not so conventional an idea, but so what, right? Cheap and effective.  Forgot to mention: This eliminates unecessary joints/splices in the loop when it is installed.

John

I went with a pair of 4" dwv lines beneath my slab for future geo install. Now I'm open loop so I pushed a drain line thru just one of the 4" lines. The second is reserved if I ever go closed loop

Thanks for the suggestions, much appreciated.

I would go with a pair of 4" DWV lines, either PVC or ABS. You could cap them with 4" rubber caps w/stainless steel band clamps - water tight but also easy to remove. I would also insure that the pipes slope downward slightly going away from the basement, >1/8" drop per foot of run or >2.5" of drop in 20' of pipe run. This would insure that if you ever did get a leak in the pipes or the end seals, any ground water would run away from the basement rather than into the basement. Then take some 1/2" or other scrap PVC pipe and stick vertically in the ground at the end of the pipes and flush with the soil to make it easier to find the end of the pipes when the time comes.

Great idea, thanks!