In message , The Natural
Philosopher writes
David Hansen wrote:
On Tue, 8 Jan 2008 19:22:59 +0000 (UTC) someone who may be Ed Sirett
wrote this:-

It might /just/ be possible to make a cost effective solar assisted
HW system if /all/ the following are true.

1) You need to replace the HW cylinder.
2) You have the time and skills necessary to make and install solar
collectors.
3) You have the time and skills needed to make the control system.
4) You have access to the scrap raw materials needed to make system.
e.g. discarded CH pump, discarded CH radiators.
If, for the sake of argument, one takes the claims of the antis of
only a 0 price increases and ignore the (low) electricity cost then a
simplistic simple payback period calculation for the Navitron Budget
Solar Kit http://www.navitron.org.uk/pricelist.htm is about 22 years
(0
And assuming you didn't have to borrow the money, in which case its a
net loser forever.

Better idea. Put the money on a bank paying 4% and have it earn you
236% return over 22 years.

4% ?

a bit NFN



--
geoff