Jules Richardson wrote:
On Wed, 24 Mar 2010 15:36:11 -0700, wrote:
http://en.wikipedia.org/wiki/GSHP.

The initial costs are considerable though

Where are the costs, though? The way I understand it, it's mostly in the
labour involved in installing the ground loops - which, given the nature
of this group, *could* be handled by the home owner.


thats nothing you can do yourself in a couole of days with a mini digger.
Problems I have he

1) Knowledge Commercial installers seem to have the market pretty well
sewn up, and there's comparatively little design knowledge in the public
domain,


I di a load of reserach.

teh main costs were not in the ground loop - I coudld easily do that
myself, and the people I spoke to were almost relieved that I would,
but in te heat pump units themselves - at leats 5-6k, and probably more,
and in the electricity supply - they really need a massive amount of
startup power even on soft start units. In fact the guyt never did get
back to me to explain why a 15Kw unit at an alleged 4:1 step up of input
power to heat out, needed a 25Kw supply..

Finallyy, there is a hiddne cost that basically made the project
unviable in my case. Although my ground floor is largely UFH and highly
suitable, the hot water and upstairs circuits are radiators and a sealed
tank, neither of which, or the ancillary pipework were sized for 'lots
of warm' rather than ;'a little hot' water. Esssentially I would have
had to rip out and replace the mains pressure tank, all the upstairs
heating circuits and double up on the radiators and towel rails.


2) My 'leccy company gives a huge discount for having a GSHP, but only if
it's a commercial system fitted by 'professional' installers,


therss always a catch.

3) I can get tax breaks for a GSHP, but hit the same problem as in 2
above.

I have always found that any government grant costs precisely as much to
achieve as it pays back, within 10%, every time I have investigated one.

I regard them as mere spin.



as time goes on that'll hopefully change - design books will appear,
parts will be available off the shelf etc.


Parts are available, BUT the real problem is that its a totally green
field install. Almost nothing you have in place will be suitable.


Retrofitting is not really an option. Its rip out, redesign and replace
just about all the pipework and heating system.

Also note that if your ground goes below -5 at deep levels, it may not
work at all.




cheers

Jules