DIYbanter - View Single Post

wrote:

Mark wrote:
Ed Sirett wrote in message

If you'd payed a lot (£2,000 say) for the system then I have no doubt
you'd not recover the cost. What might be the threshhold?

That's still a moving target, how much will energy prices have to
increase before we can't afford NOT to fit some type of solar heating.

another good question, and another bastion of solar DHW support. So,
lets find out:

At todays prices a £2000 commercial system saves in the region of £20
per annum on hot water bills.

I don't know how you get your figures, but the average North American uses
some 40 THOUSAND US gallons of hot water yearly. The water heater usually
runs in excess of 120F, from a coldwater supply well below 70F. Raising
40,000gal * 50F = 320,000lb * 50F = 16,000,000 BTU, which if I am not
mistaken is going to cost around $25/million BTU to heat. So that comes
out to $400/year. A tad more than £20, and well worth replacing even with
a system that only generates half your hot water.

Ack! I'm beginning to sound like Nick. GOTO 100.
--
derek