Solar hot water?

**Laava** · 29th August 2013, 20:20

Thinking about putting in a new system but would like feedback from anyone who has one.
Esp if they have had it from new and all pros and cons etc. I have done some research but would like owner feedback.
TIA.

**BMWST?** · 29th August 2013, 22:37

Originally Posted by Laava

Thinking about putting in a new system but would like feedback from anyone who has one.
Esp if they have had it from new and all pros and cons etc. I have done some research but would like owner feedback.
TIA.

this is what i have found out ..I dont have a system but have doen a bit of research into whats available
vacumn tubes systems are more efficient,but are more expensive.Flat panels are cheaper but less efficent than vacumn tubes.Best effidiency is witth active systems ,ie pumps,not just relying on thermal siphoning.Some say that vacumn tubes systems are best reserved where larger volumes or higher temperature temps are needed.
Good luck i find it very difficult to find someone who talks any sense.One fella told me the payback was 12 years which i thought rather strange when the system warranty for the panels was only 10 years.He was very flustered when i pointed out this anomoly.

**pzkpfw** · 29th August 2013, 23:14

It was great in Fiji.

**shafty** · 29th August 2013, 23:37

Hi Laava, do a thread search cos I have seen an extensive thread covering this topic and "going off the grid" on here somewhere - would look for you but rushing out the door to work, good luck

**Laava** · 30th August 2013, 07:23

Originally Posted by shafty

Hi Laava, do a thread search cos I have seen an extensive thread covering this topic and "going off the grid" on here somewhere - would look for you but rushing out the door to work, good luck

Thanks guys, i did a search but found nothing initially. Fiji sounds great but hard to get through customs.
Hoping to get info from someone who has fitted and run one for a few years. I know the initial outlay is quite a bit but the drop in the power bill is the bit I am interested in.

**p.dath** · 30th August 2013, 07:40

I have often thought about solar hot water versus solar power, and always seem to come to the conclusion you would be better off getting solar power (staying on grid, no batteries).

The problem I have with solar hot water is once your water is hot any additional solar energy harnessed is wasted. With solar power the electricity generated can still be used to power your hot water cylinder, but once that is heated the excess power can continue to be used to power other devices in your home, reducing your power bill.

There is also a global glut of electric solar panels ...

**Banditbandit** · 30th August 2013, 08:53

We had solar heating for the water on our small farm in Hawke's Bay. It was the type that had an electricity option, with an on/off swith coupled to a thermometer reader in the kitchen so we could see what the water temperature was, and switch on the electricity if it needed it. It was also hooked up to our wood stove through a wetback, so we had three ways to heat the water - electricity as optional. During winter we ran it on the power at night so there was hot water in the morning - but I'm talking winter in the snow country here.

It's hard to know if there was a drop in electricity bills. My wife said yes there was, but I'm not convinced. Part of the problem was that when we installed it electricity prices were rising quite frequently. It's hard to know whether our power use was less than previously - I suspect it probably was, but the rise in electricity prices meant it didn't look like we saved much per month.

I would not say, on that basis, that it is not worth it. I might not put one in if I still lived in the high country - it's certainly an option here, as we have some of the highest sunshine hours in the country ...

**Erelyes** · 30th August 2013, 09:15

Originally Posted by shafty

Hi Laava, do a thread search cos I have seen an extensive thread covering this topic and "going off the grid" on here somewhere - would look for you but rushing out the door to work, good luck

http://www.kiwibiker.co.nz/forums/sh...-on-their-roof ?

**mansell** · 30th August 2013, 09:33

A few years ago I lived in a house with an old (15-20 years) passive solar water heating system backed up by the thermostatically controlled electricity system. At the time there were 4 adults and two kids living there and there was always sufficient hot water. I am sure it severely reduced our power bill but as the system was installed well before I moved in there was nothing to compare it with, except the odd conversation with other people living in the area. Logically it must save money as a large chunk of ant power bill goes on hot water. The big concern was the water in the header tannk sometimes reached boiling point, however a simple thermostat controlled valve would probably remedy this. We have discussed this as a option for the house I currently own and will probably install a system once the rest of the renovations are complete.

**Edbear** · 30th August 2013, 09:55

Don't have it myself, but if you want to know all the systems and combinations available including custom made to suit your own needs, call these guys and ask for Rudy. www.europlumbing.co.nz

**Road kill** · 30th August 2013, 17:27

Originally Posted by Laava

Thanks guys, i did a search but found nothing initially. Fiji sounds great but hard to get through customs.
Hoping to get info from someone who has fitted and run one for a few years. I know the initial outlay is quite a bit but the drop in the power bill is the bit I am interested in.

If you want to save money then turn your Hot water cylinder off for 12 hours a day.

We've been saving around $80 per power bill since we started doing this at the beginning of last winter.

**pete-blen** · 30th August 2013, 17:44

A vacumn tube system lets you boil the water at lower temps

i use to work for Dom salt we had what was basicly a crude desalination plant
It would boil water at 42*C under 4 hegs of vacumn..
basicly the reverse of your bike/cars cooling system.... Put it under pressure
& yer raise the boiling point...
so the vacumn tube would have to work better on colder days/winter...
a home system won't pull anything like 4 hegs..but even half a heg will
lower the boiling point...

**pzkpfw** · 30th August 2013, 17:49

Originally Posted by pete-blen

A vacumn tube system lets you boil the water at lower temps

i use to work for Dom salt we had what was basicly a crude desalination plant
It would boil water at 42*C under 4 hegs of vacumn..
basicly the reverse of your bike/cars cooling system.... Put it under pressure
& yer raise the boiling point...
so the vacumn tube would have to work better on colder days/winter...
a home system won't pull anything like 4 hegs..but even half a heg will
lower the boiling point...

That might change the boiling point, and be useful for desalination, but isn't changing the heat content of the water; so not useful for making a nice hot shower.

e.g. http://en.wikipedia.org/wiki/High_altitude_cooking