Anna Kettle wrote:
On 26 Dec 2006 07:01:49 -0800, wrote:
To kick off...
insulation insulation insulation
solar hw can pay back but too often doesnt.
solar warm air can give good ROI
underground pipes can give a nice return as an ac substitute
solar pv forget it
windgens in inhabited areas forget it
shower drain heat exchanger can pay back well
passive cooling avoids much ac
deciduous climber on house walls producng fruit gives summer colling &
food, but must be kept off the roof. High ROI.
CFLs god ROI
Thats an interesting list and I'm glad to see that I have all the
sensible ones installed or planned, except a shower-drain heat
exchanger, which is a new one on me. Can you elaborate?
Anna
Sure. In a diy incarnation its a piece of metal waste pipe with
microbore wrapped round it. The 4 lengths of microbore wrapped in
parallel connect to a 4 way manifold at each end.
The idea is as the warm shower waste water flows one way, the cold feed
to the shower flows the other way thru the 4 microbores. This makes a
crossflow heat exchanger, giving you a lukewarm cold feed to the shower
and thus reducing hot water use.
In the right situations they can give over 50% ROI, but in Britain they
will generally be nonideal implementations, but still be a good long
term investment when fitting a bathroom.
NT