Anyone know about solar hot water? My boiler has blown up. Whilst British Gas will probably patch it up, it generally sounds ill and will pop for good before long. I had a guy in today to quote for solar hot water. They only sell the modern evacuated tubes and together with a tank fitted to the loft, plus all the piping etc, he wants £7100. Thats after the 25% discount for having their sign on the front of the house for 8 weeks as advertising. Is that a lot? I was expecting £5000 ish.

He also wants £3000 to fit a new boiler, which also sounds a lot.

You can get a grant for this type of work I believe...?

You need to be sure you are not moving for the next 20 years, or else it is unlikely to pay for itself.

Much as the theory of it all really grabs me, I'm afraid it wouldn't be me at that sort of price.
How long would be payback be ?

The evacuated tubes don't need direct sunlight, just light. so they provide most of your hot water in the winter and all of it in the summer. Work out how much you spend of Gas and work out your payback period.

I'm told that a solar system adds 9 - 10% to your house value, not that we're planning to move, but if you're a light gas user payback may be quicker if you move house.

I know that salesmen are full of it but one thing that he said was all bull. He reckoned that a full tank of 95° hot water took 1 hour on a cloudy winter day and 20 minutes on a sunny summer day. From his literature and common sense, his solar panel will heat the tank by 10°C per hour in full sun and maybe 7° when cloudy.

[Edited on 23-2-2008 by smart51]

sorry to have to say it but solar hot water is not cheap and the pay back time is about 12 to 15 years depending on size of house number of bathrooms etc good selling point if you ever move but it remains to be seen whether or not people will pay a premium for it as yet the evacuated tubes are slihjtly more efficent than the panel type but are more prone to problems as in broken seals allowing the gas to escape and did he ssay weather it was a drain back system or constantly filled as the drain back systems can be a bit noisy. the three grand for doing the boiler sounds a bit excessive if you can tell me what this included including size and model of boiler i shoiuld be able to give you a good idea on that one have a look on the worcester bosch web site and search for your local green skies installer they are offering preety good grants at the moment

Contact these people & see what they say. They did my cavity wall insulation and seemed pretty good.

Even explained why solar wouldn't be good for me. (i already knew, but it was nice having someone NOT sell me something).

http://www.rockwarm.co.uk/index.php

Personally, I wouldn't deal with a company that are prepared to knock £1800 off the price for just putting a sign in the garden. They obviously are employing well recognised sales techniques.
What about you ring thme back and tell them they can have a bigger sign, for 32 weeks, but you want the system installed for £12.47.
On a serious note though, they've probably got quite a lot of profit margin left at £7100. Why not ring them back and say £7000 with the boiler and you've got the job. They can only say no.
3k is hefty for the boiler swap - assuming it's a straightforward change over.

I manage properties for a living and I generally pay £1500 for a boiler swap and that's for a Worcester Bosch which is generally considered one of the best.

No idea on the solar stuff

Cheers

Mark

Try and get a recommendation from a friend of a good local plumber - I would agree that £1500 is about right for a regular boiler swap - make sure it's a decent make.

i have designed one to heat my pool in spain it is 100% solar powerd solar panel to spin the pump and copper micibore painted mat black to take the heat coiled up in an insulated box whit a glass lid to keep the heat in ,it was very easy to make and works great.

Payback periods - the real calculation

Put the £7100 in a high interest account and work out the annual interest.

Deduct the hot water cost that you would incurr using your existing gas system.

I am in no doubt that year on year the money in your account will grow.

For the Solar

The £7100 is gone and you have service agreements and the annual running costs of the pumps and controls that are electrically operated. + the gas and electrical use when the solar cannot perform effectively honestly that is 40% of the time.

They dont work at night and in the winter our daylight hours are short.

Give the salesman the calculation and ask him the payback period.

How often does the pumped medium need replacing? - what protects from legionella?

Is your loft capable of holding the weight of the cylinder and whats the storage capacity?

Andrew

Ex technical manager of one of the worlds leading manufacturer of renewable heating solutions

Have you considered Air or ground source heatpumps instead?

I have just finished a two year project involving several of these...

U2U me if you want a load of informaiton...I cant be arsed to type it in if heatpumps are not of interest to you

http://www.navitron.org.uk/pricelist.htm

"Deluxe Solar Kit
20tube panel; pitched roof mounting kit; twin coil hot water cylinder (up to172litre double insulated, Grade3 with Grade2 base); TDC3 Solar controller; Circulation Pump + isolation valves; anti-syphoning valve; pressurised system kit; 10m armaflex HT high temperature; antifreeze £1122"

Then find a plumber who wants less than 6K to fit it.

Payback time is obviously dependent on the amount of initial expenditure.

HTH

Mike

Heatpumps LOL

Not for an existing property

The Geo costs alone kill them never mind hardware costs and service up-keep of the compressors - and then there is the low grade heat produced needing underfloor heating and electric immersion heating for hot water.

COP needs to be 7 at least before they are viable and then need a 3-4 year between service life.

Put the £15K in a high interest account etc etc.

Andrew

LOL....

We just fitted an air source heatpump to a very large radiator system and hot water system....

Total heat output 23Kw, @50 degrees flow temperature....

Granted, it cost £12000....But if you wanted a much smaller heat output then the prices drop rapidly!

quote:

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Originally posted by smart51
Anyone know about solar hot water? My boiler has blown up. Whilst British Gas will probably patch it up, it generally sounds ill and will pop for good before long. I had a guy in today to quote for solar hot water. They only sell the modern evacuated tubes and together with a tank fitted to the loft, plus all the piping etc, he wants £7100. Thats after the 25% discount for having their sign on the front of the house for 8 weeks as advertising. Is that a lot? I was expecting £5000 ish.

He also wants £3000 to fit a new boiler, which also sounds a lot.

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He has a point...

Its going to take us about 15 years to make the machine pay for its self..


But if you cant have gas, and your electricity supply is limited to 60A...there isnt much you can do if you want 20Kw of heat...

Just dig a hole in the garden about 300m deep and drop some a loop of pipe down it and pump the heat from underground....

quote:

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Originally posted by Andy S
Put the £7100 in a high interest account and work out the annual interest.

Deduct the hot water cost that you would incurr using your existing gas system.

---

There was a programme on Westcountry TV about these last night. They were doing a Watchdog type programme on a scamming company called Ultimate Energy, they were originally called something else and were shut down for dodgy dealing but re-invented themselves and are at it again. Basically, lying about the efficiencies of solar water heating in their sales pitch. They had an independent expert witness who claimed that these systems will never pay for themselves in the UK and that you're better off topping up your loft lagging, etc... They were charging about £10k for a single panel system, I think the expert claimed it should cost no more than £4.5k!

A replacement combi boiler should cost £2200 max fitted.

Not Westcountry TV but BBC South West, there's a link BBC

I've just done a payback calculation based on saving 1/4 of my gas bill and based on gas prices rising at 5% per year. 61 years. I have an environmental conscience but not that much.

In the average UK winter day it is not viable get high grade heat from solar energy alone.
If used for domestic hot water the temperature of stored water must be kept above high enough at all points in the storage tank and system or you run into the danger of water born bugs eg Legionella, E-coli, Cryptosporidium.


Legionella is the bigest threat in a domestic hot water system .

* 70 to 80 °C (158 to 176 °F) - Disinfection range
* At 66 °C (151 °F) - Legionellae die within 2 minutes
* At 60 °C (140 °F) - Legionellae die within 32 minutes
* At 55 °C (131 °F) - Legionellae die within 5 to 6 hours
* 50 to 55 °C (122 to 131 °F) - They can survive but do not multiply
* 20 to 50 °C (68 to 122 °F)- Legionellae growth range
* 35 to 46 °C (95 to 115 °F) - Ideal growth range
* Below 20 °C (68 °F) - Legionellae can survive but are dormant.

Unless the hot water temperature is over 65c at all points in the storage tank 65c and at point of use the water temperature reaches >60c within 1 minute it is a potential major threat to your health.

With legionella the danger is inhaling a tiny infectect water droplet, in a domestic situation this could be from a shower

http://en.wikipedia.org/wiki/Legionaires_disease

[Edited on 23/2/08 by britishtrident]

Water only remember - Not heating not cooking.

quote:

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Originally posted by smart51

quote:

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Originally posted by Andy S
Put the £7100 in a high interest account and work out the annual interest.

Deduct the hot water cost that you would incurr using your existing gas system.

---

£7100 @ 5% interest, less tax = £24 per month.
Less 1/2 of monthly gas bill = not a lot.

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A locostbuilders thread & no-one has mentioned DIY.....!!!
The evacuated tube panels alone would only be a few hundred quid. (plenty on ebay)
Swop the cylinder for one with an extra coil at the bottom & have a closed circuit for the solar (keep the bugs sealed inside....)
The long payback woes are for photovoltaics, thermal is a lot cheaper & more efficient. If the cost is 1k£ + some effort, it starts to look rather more promising.
I'm thinking about it for an unused section of wall at the south side of my house.....

Can't you build a locost version using black alcathyne pipe and a central heating pump!!!

IIRC They can't put a sign up for longer than 8 weeks past the completion date as it then requires planning consent

The one on my mind at the min is preheating your water before it enters the shower, either from a heat exchanger in the waste pipe or maybe solar to add a few degrees to it. Wouldnt save money but would make the shower flow a bit better!

Im sure there is some merit to simple log fires, you can find free fuel and with a bit of bodging get warm water too.

And if you use damp logs with a bit of moss on them , it smells fantastic as well.

There was a programme on Tv last year , I think it was rogue traders that looked into solar heating and found lots of companys with exagerated claims.
To heat your tank that quickly would requrire a few kws of heat and its not likely to come from a solar panel.
I have a south facing end wall to my house and a flat garage roof and looked into it but it didnt seem worth all the effort, although having seen my last gas and electric bill may think about it again, or better still look into a simple combined heat and power unit if i can find a suitable generator cheap.
Paul.

quote:

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Originally posted by smart51
The evacuated tubes don't need direct sunlight, just light. so they provide most of your hot water in the winter and all of it in the summer. Work out how much you spend of Gas and work out your payback period.

I'm told that a solar system adds 9 - 10% to your house value, not that we're planning to move, but if you're a light gas user payback may be quicker if you move house.

I know that salesmen are full of it but one thing that he said was all bull. He reckoned that a full tank of 95° hot water took 1 hour on a cloudy winter day and 20 minutes on a sunny summer day. From his literature and common sense, his solar panel will heat the tank by 10°C per hour in full sun and maybe 7° when cloudy.

[Edited on 23-2-2008 by smart51]

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The systems ive seen have a separate circuit for the heated water with a heat exchanger to transfer to the boiler feed. Im guessing legionnaire's disease is less of an issue in these cases.

If your interested in a system, read up on how they work. Look at available systems and install it yourself. Makes the payback more attractive.

I had a lecture at uni a couple of weeks back about the systems from the UK's foremost authority (alegedly) on them. He was saying some interesting things and how its quite beneficial even with homemade systems. Apparently Scotlands one of the most optimal places to have solar heating in Europe.

We have a solar water heating system intalled in our house. It was installed by the previous owners. There are four panels on the roof (the technology of which I have not explored). There is a controller which switches on a small electric pump when the panel temperature is higher than the temperature in the tank by a certain amount. We have a much larger than normal dual coil tank installed.

We do not get any gains during winter conditions because of our location and daylight hours therefore revert to gas. From mid March onwards all of our water heating is provided from the solar panels. From May to August heated Water temperatures are from 65-80 degrees.

We had little or no idea about the system when we purchase the property but with increasing energy prices it has been a godsend.

Cheers
James

Here's a DIY system

http://www.builditsolar.com/Projects/WaterHeating/MSClosedLoop.pdf

I was looking at making my own system for a holiday home, as the choice is freezing cold water all the time or solar.
It is mainly pipes painted black, glass to insulate/let ir energy in and a black back panel to convert the ir to a longer wavelength so the heat does not radiate back through the glass.

Darren

Solar energy arriving at earth is about 1kW/sq m so yes, a few kilowatts IS available. Complete DIY systems are often something like a black painted radiator in an insulated box with a glass lid. These are a bit inconvenient to plumb & losses are high so they don't work so well in winter. The vacuum flask ones are less lossy & use heat pipes to carry the heat to a manifold at a single end, so basically you have to buy 'em. They're the "few hundred quid" option I talked about above. You can expect such a system to raise the water temp in the cylinder by 10K in winter - not enough to use directly but still it's 10K you DON'T have to find by burning gas.
I agree the "green bandwagon" firms are disgraceful in the way they make preposterous claims to dupe well meaning folk. I've heard heat pumps described as "free heating" - when best case it's 1/3 cost electric heating AFTER a massive installation cost.
The most disgraceful thing I'd heard for a while was on the news this morning - some old guy had trouble with his boiler last week when it was freezing, & he was on the maintenance deal with british gas. Because of a small leak they condemned his boiler, locked it off & made him stump up 7grand to fix it. I was outraged, they might as well have put a gun to his head. He's since got competitive quotes averaging 2 grand..

The gas companies are famous for their prices being outrageous.

In my line of work we have to ask people to get two quotes for their works. For heating, most used to get Scottish gas out to quote but they (Scottish Gas) are refusing to do it now as they know that they will be between two and three times the cost of everyone else.

another alternative is dig a hole where your gas comes in ( a lot are plastic pipes now) put a tee piece in and run that into your house past the meter for instant half price or even free gas,going rate is about £500 .electric is more expensive as you need a switch either in the meter box or inside before the consumer board.i have NOT done this for the last five years with no problems

^^^^

Eh?