Hi my local geo loop installer says that he trenchs his two pipe horizontal at 5ftand 3.5ft.Most of what I have researched recommends 6ft and 4 ft.He says he has installed for ten years in Illinois ,Iowa,Indiana and Missouri and thats all it needs.I live in So Illinois and wonder if those depths are alright or will I lose a lot of effiency.Thanks for any advice

The loop will perform fine at 5 & 3.5. You might lose a little efficiency. The difference in ground temp from 5' to 6' is not much.

OSHA rules don't allow working in a trench over 5' deep. There are ways to position the pipe with out being in the trench, but require more work. Is he using a trencher or back hoe? 5' is probably all the deeper a trencher will go.

Thanks Dewayne ,for the advice.He uses a trencher and says he's never had any problem.