Solar Panel Question

pdelahunty

Posting this again as I received no replies as I think I posted in to an incorrect group.

I live in a typical estate of typical semi-Ds (3 bedrooms, smallish) so our house is relatively small. For a while I have been considering getting solar panels for our hot water needs. We have a large hot water tank and a pump on our shower but we don't need a massive amount of hot water. Right now we use our gas during the summer only to hear water for showers / baths etc.

Does anyone have any advice on

(a) economically whether it is worth it? I don't want to save a ton of money but I would like to know I will break even over time
(b) Are there different types and are there any to avoid
(c) Whether I am nuts for even considering it

I hope this is the right forum but please let me know if there is a more appropriate one,

Thanks

shane0007

A) it really depends on the amount of hot water you use. People really under-estimate the amount of hot water they actually use. For example, a standard pumped power shower can generate a flow rate of 15 litres per minute, so a 10 minute shower is 150 litres at full flow. As it is thermostatically controlled, it will not be 150 litres of hot from the cylinder but depending on the water temp in the cylinder, probably in the realms of 60% (90 litres) will have come from the cylinder. A standard cylinder is 136 litres. It is not noticeable as the cylinder, unless zoned, is being re-heated all the time the heating is on.
The payback time for solar, depending on usage, is anywhere from 6 - 12 years. A big range but a family of 4 is usually 8 - 10 year payback.
Yes, there are many types and many to avoid. Flat plate are probably cheapest but do not work as well in cloudier & colder weather. Tubes give a better overall performance. When the sun is shining on them, both will perform quite equally. Kingspan tubes come with a 20 year warranty on the tubes. I shouldn't really name ones to avoid but do as much homework as you can. Don't go by sales talk. Get true recommendations from people who have them. I installed mine about 4 years ago and am very happy with them.
C) No, you are not but do your homework so you can make an informed decision.

corkgsxr

Imo the payback is much longer. More like 15 year if nothing goes wrong.

But prices have come down so payback may be shorter.

Bear in mind your ment to flush and put in new glycol every 2-3 years. More cost.

If anyone id go kingspan. But in Ireland im not a fan of solar panels.


Was in a house about a year ago. Man was delighted with his solar panels. Funny thing was he has a electric shower. Asked him what do ya use it for.

"Well I have a bath once or twice a month"

Didn't comment

paddy147

corkgsxr wrote: »

Imo the payback is much longer. More like 15 year if nothing goes wrong.

But prices have come down so payback may be shorter.

Bear in mind your ment to flush and put in new glycol every 2-3 years. More cost.

If anyone id go kingspan. But in Ireland im not a fan of solar panels.


Was in a house about a year ago. Man was delighted with his solar panels. Funny thing was he has a electric shower. Asked him what do ya use it for.

"Well I have a bath once or twice a month"

Didn't comment

Solar panel system and a nice big rainfall shower from the solar..........cant beat it.:D

shane0007

corkgsxr wrote: »

Bear in mind your ment to flush and put in new glycol every 2-3 years. More cost.

True for most solar systems, but Kingspan has a built in patented anti-stagnation device in the tube condenser. Due to this, replacement of glycol is not required for 5 - 10 years. This would not eliminate the need to check the glycol properties every year with a refractometer.

freddyuk

paddy147 wrote: »

Solar panel system and a nice big rainfall shower from the solar..........cant beat it.:D

You have Thermodynamic not solar thermal.!!

It is not necessary to replace the glycol every 2 years or even 7 years as per Kingspan as you can get fluid that will survive stagnation. if you buy the proper product maintenance is reduced but most will get the cheapest glycol which will fail if the system stagnates but then the system should not stagnate if proper controls are in place so it really depends on who installed your system and how good they were and how much you were prepared to pay.
As for the Kingspan guarantee it is full of loopholes like most guarantees and requires an annual inspection which needs to be added to your capital costs. If the system experiences excessive temperatures then the guarantee becomes void. You the customer are required to check the status of the temperatures of the system. There is a "fair wear and tear" clause which will cover most eventualities in a stressed hot water system. ie. if the famous anti stagnation valve fails to operate is that fair wear and tear after x number of years?
I would be prepared to pay a lot less and get a system that just works. If a tube fails it cost €15 to replace. I would have a bypass fitted so stagnation is limited or excluded entirely.
The full terms of the Kingspan warranty can be found on their website.
Has anyone actually successfully claimed against it? The way I read it if one tube is replaced under warranty then that's it, they are off the hook from then on. I could be wrong but warranties tend to be down to interpretation and that is the issue with this one.
Get simple technology with simple safeguards and leave the court room out of the equation.

Mysticmak

In terms of payback time, has anyone worked into the equation that fuel oil, gas and electricity will not in fact be going down in price over the next 5-10 years, surely the reduced dependancy on fossil fuels will be an additional saving?

dfin

Here's a report on the field trials of 88 installations in the UK and Ireland over a 12 month period. Figures are in sterling it's a couple of years old but still worth a read.

Average cost £4800 of installation
Average Saving £55 for gas - (max saving was of £100plus)
According to their results pay back would be roughly between 40 and 80 years! :eek:


"Overall, the results are positive, and they illustrate that if the system is ,installed and used correctly, solar waterheating systems can be an efficient way of providing domestic hot water.Customer behaviour can also make a significant difference to how effectively the generated heat is used. A number of systems, which demonstrated lower levels of performance than anticipated,did not fulfil these criteria."
Here comes the sun: a field trial of solar water heating systems
The Energy Saving Trust

I have no experience of flat plate type. I have seen the tube type (HP200) work very well although some excessively high temperatures have been recorded which if sustained would lead to breakdown of the glycol - even though they say the tubes have an inbuilt temperature limiting mechanism.

You're not nuts, alot of people get this installed for reasons other than financial