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re: solar water heating system value
7 mar 2006
samc wrote:
>meow2222@care2.com wrote:
>> lets say it saves £20 a year heating dhw only.
would that be 20 uk pounds per year? sounds like a very poor water heater.
it seems to me that american families pay about $20 per month for hot water.
>> lets say we want it to break even after 10 years, interest is 5%...
>> a system that does this in 10 years is worth paying £157 for now.
would you believe 154.43 pounds?
>>>from this emerges one clear conclusion: we need either a lot more
>> saving or a lot less cost than commercial solar dhw systems deliver.
or both. solar water heaters are typically undersized and overpriced.
>> if one got a bit desperate and justified a 20 year payback, system
>> value would rise to £251.
would you believe 249.24 pounds?
>> now, since almost all solar dhw setups fail miserably to pay their way,
>> lets see how low cost we can get. start with a dirt cheap direct
>> drain-down system for summer use only.
there's no reason a draindown system can't work in wintertime.
>> collector and loft piping:
>> 100' garden hosepipe: £20
>> sheet of green house polythene: £? lets say we use a £1 poundland
>> plastic patio table cover set...
how about a solar-pond type water heater instead?
>people are looking at this the wrong way givern the above would any one
>ever buy a car,computer,tv e.t.c .
it's more rational to say
i need hot water. what's the most economical system?
nick
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