Hi. I'm preparing to remodel my house, and I was thinking it would be a good time to consider a GSHP. My house is 2.5 stories on a 600 SF footpring (i.e., 4 levels, 2400 SF). I am considering adding 300 SF on 4 levels, for a total of 3600 SF. My property is just 5000 Square feet. I was thinking that I will be digging a hole 14' x 25', 6 feet deep. Would it make sense to plan on digging deeper, and put a closed loop under the slab?. It should cost half as much to dig this deep as to start from the grass and dig down. Can they be laid in layers? or paralleled about 1' apart? how about in layers? Dig down 9', put in loops, fill 3', put in more. It seems the risk is that a problem would cost a fortune to fix, because it is under 2' of concrete. Also looking for references or installers in Northern NJ or NY Metro area. Thanks Seth userid: my name at nevjersey dot org
If you get a contractor who understands GeoThermal installs, he will tell you how far down each hole goes and how far apart they are. My 1700 sq ft house required 2 450FT holes for a closed loop system. I would say the holes were about 30 ft apart. I'm on a 1/3 of an acre. Very tight. Had it done last year. Couldn't be more happier on the outcome. Good luck
Engineered backfill The costs associated with engineered backfilling to your required house grade will defeat any economic gains in this manner. Drilling may be the best option, and this is a beneath foundation option as well.
