On Mon, 20 Jul 2009 06:57:40 -0700, js.b1 wrote:

On Jul 20, 1:34Â*pm, Jules
wrote:
My only worry there is whether whatever I seal them in will
somehow distort the readings.

Temperature-delta per unit time is pretty minimal.
Insulation is not perfect, it just slows the rate of change & may miss
transients.

Ta - makes sense

Would be more useful to know you have "nothing else down there".
Going thro the local gas main is rather novel... GasSHP :-)

Around here there's an online service where you can request a (free)
site survey - they'll then contact the relevant folks (telecomms, power
etc.) who'll come out and mark out where all of their stuff is for you. It
all works rather well (just been through it prior to planting some trees
out front - 48hr turnaround, which isn't bad).

No gas main or water main here; gas is via an LPG tank and water's via a
drilled well - although it's still useful to avoid digging through the
lines

It gets too cold around here for ASHP to work, but I believe GSHP is
possible given a big enough / deep enough loop.

cheers

Jules