Solar water heating

[Derek Broughton]

You can risk it. I'm investing in the glycol flat-panel system.

[Harry Chickpea]

Make an error on usenet? That usually provides plenty of free hot water.

[Mary Fisher]

My neighbour used to tell me that only mucky people have baths...

Mary

[S Viemeister]

Where did you get your figures? About 25 years ago, I was living in a drought-stricken area of the US. Limits were put on water use - 50 US gallons per person per day. That was for ALL water, not just the heated stuff. The only thing that suffered was the garden - which wouldn't have been using heated water, anyway.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Mary Fisher" saying something like:

He probably couldn't be bothered taking the coal out of it.

[Ron Purvis]

[Mary Fisher]

You're making asumptions. Plural.

[AJH]

heat falling on the surface of the panel. To make a judgment I need to know how much of that heat arrives during the space heating season and how much in the water heating season.

It's the same with wind, an average 7m/sec doesn't mean much when the actual potential is proportional to windspeed^3. A gusty December day could average the same as a steady breeze in June but it produces more power and probably when it is better needed.

AJH

[meow2222]

The figures in this thread have stated the savings amount required to make it worthwhile. If you think you can save well over =A3100 a year with a =A32000 water heater, go for it. I dont.

NT

[meow2222]

Welcome to uk.diy Nick. Yes, its 20 uk pounds. I'm not sure how you use all that hot water :)

NT

[meow2222]

Welcome to uk.diy Nick. Maybe you can give them a pointer or 2 on how to make a constructive DHW system that pays its way, too much talk of junk designs here.

Yes, its 20 uk pounds. I'm not sure how you use all that hot water :)

NT

[meow2222]

Nick's point was that a draindown system without antifreeze can be designed to be safe in winter.

NT

[meow2222]

We dont spend that much here.

Half your how water would be $200 a year, roughly =A3100 per annum. It would take - as said before - the remaining life of the universe to pay this off, if there were zero risk of it ever needing repair etc.

We arent average north americans.

NT

[Guy King]

The message from [e-mail] contains these words:

Well, they have to bath the car once a week. (insert pseudo-smiley)

[Derek Broughton]

LOL. I accept that North Americans are much more wasteful of water - heated or not - than Europeans, but a difference of $400+ to £20 for the cost of heating that water just doesn't make sense.

[Derek Broughton]

I know what his point was. He might even be right. I, however, have no intention of risking it. I can, and will, profitably install a glycol loop system with heat exchanger.

[Derek Broughton]

The "figures" are a ridiculously low number for cost of hot water that you made up. I can _easily_ save £100 a year with a system that will cost me about that much. Check back next year for real use figures...

[Derek Broughton]

I expect not. But £20 is simply fraudulent.

Why half? I can get 80% at least. You only do laundry when the sun's out (which is true anyway because I'm off grid), you take showers in the afternoon, and do dishes in the evening.

Ho, hum. The locally built glycol systems have a proven track record of costing an average of $100/20 years for maintenance.

[Derek Broughton]

OK, I'll accept those numbers. Anyone got a better figure on the average cost of heating water? My numbers for heat required are, if anything, on the low side, but at $25/million BTU, and only 25,000 gallons per year, you're talking $250/year (somebody else said $20/month, so same ballpark). Still plenty to make a commercial solar water heater pay off.

[Derek Broughton]

See Ron's cite - I'll grant you that you don't _need_ to use 50 gallons of hot water, but the average family does, anyway. You're right, that's not

40,000 per year, but still an order of magnitude above Meow's figure.