Solar hot water seems to be the most efficient use of solar energy. Who has experience of fitting this to their house?.
I was thinking of getting the solartwin kit at ?2000, anyone know of a more cost effective product?
Let's get some info up on the best products along these lines ie;- Affordability / Efficiency.
Solar Hot water heating
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Solar Hot water heating
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You could always try building your own. I tried to go on a course to do that a few years ago but it was canceled due to lack of interest 
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Guest
As a heating engineer (who is currently off work due to injury) I have fitted both the Solartwin system and more sophisticated evacuated tube systems. The jury's out on how good each system is overall, especially when you take into account reliability, maintenance cost, usability, installation price, durability and so on. The Solartwin model is certainly one of the simplest and requires little user involvement and since it powers itself, requires no electrical input. It's efficiency is less than some however although it should give 100% in summer (that is a full tank of 60 degree water throughout a sunny, hot day). In winter it will give more like 20%.
Evacuated tube models tend to give better efficiencies and can provide up to 50% in winter but cost more and need more maintenance. They also require electricity and more sophisticated controls (adding to the maintenance and usability problems)
Overall, the decision is not a straightforward one. I would definitely say approach the manufacturers direct for lists of reputable installers and advisers. There are lots of rip off guys out there. If you are quoted more than about ?3500 all in for a basic system including fitting then there is something wrong. (?8000 is not uncommon and is just theft in my opinion).?400 grant is also available in England and Wales but only if it is professionally installed - not DIY. Scotland is ?300 I think)
Building your own is certainly a good idea and will save lots of money. CAT does a great little booklet on the subject http://www.cat.org.uk/catpubs/book.tmpl?sku=swh
In terms of cost, bear this in mind. A typical family house will spend ?100-?150 on hot water (more if electricity is used). If overall annual efficiency of the solar system is say 50% then you will save ?50-?75 per year. If it costs ?3000 to fit then it will take 40-60 years to pay back. Of course, as energy prices rise, the pay back period will drop and you will be helping to reduce CO2 emissions also.
Evacuated tube models tend to give better efficiencies and can provide up to 50% in winter but cost more and need more maintenance. They also require electricity and more sophisticated controls (adding to the maintenance and usability problems)
Overall, the decision is not a straightforward one. I would definitely say approach the manufacturers direct for lists of reputable installers and advisers. There are lots of rip off guys out there. If you are quoted more than about ?3500 all in for a basic system including fitting then there is something wrong. (?8000 is not uncommon and is just theft in my opinion).?400 grant is also available in England and Wales but only if it is professionally installed - not DIY. Scotland is ?300 I think)
Building your own is certainly a good idea and will save lots of money. CAT does a great little booklet on the subject http://www.cat.org.uk/catpubs/book.tmpl?sku=swh
In terms of cost, bear this in mind. A typical family house will spend ?100-?150 on hot water (more if electricity is used). If overall annual efficiency of the solar system is say 50% then you will save ?50-?75 per year. If it costs ?3000 to fit then it will take 40-60 years to pay back. Of course, as energy prices rise, the pay back period will drop and you will be helping to reduce CO2 emissions also.
Note the SolarTwin does not work with Combi boilers.
At the FTF conference there was an Austrian solar-with-wood-chip (or pellet) "shed" that provided hot water for about 3 homes. I'll try and find out more about it.
At the FTF conference there was an Austrian solar-with-wood-chip (or pellet) "shed" that provided hot water for about 3 homes. I'll try and find out more about it.
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Guest
As for Solartwin, the hardest bit is installing the panel which is large and awkward to handle. It weighs only about 25kg but on a roof even that can seem a lot more. The instructions that come with Solartwin are very comprehensive but fitting the panel does require that you drill through your slates or tiles and they are of course prone to breaking. You need to drill 6 holes in all through the roof using size 8 and 10 drill bits if I recall (or it might be 10/12 bits, I can't quite remember). The inside work is easy if the cylinder and water tank pipe work is close by. Mostly it's just time consuming.
If you go down the DIY route then you won't be given the full gurantees and backup if anything goes wrong. If you have it installed by Solartwin themselves then you pay a bit more but you will qualify for the grant which will offset most of that.
As for combi boilers, it is possible to use Solartwin but you need to install an additional cylinder (mains fed cylinder commonly called an unvented cylinder). The Solartwin panel is then connected to that new cylinder via a new feed and expansion tank, which is also required to be installed, and the water it heats then passes from the cylinder and into the combi boiler when a hot tap is turned on. Basically it means the boiler doesn't have to work so hard (thereby using less energy) because the water passing through it is already warm /hot. Unvented cylinders can only be fitted by qualified, registered, installers unless you can comply with part G of building regs.
If you go down the DIY route then you won't be given the full gurantees and backup if anything goes wrong. If you have it installed by Solartwin themselves then you pay a bit more but you will qualify for the grant which will offset most of that.
As for combi boilers, it is possible to use Solartwin but you need to install an additional cylinder (mains fed cylinder commonly called an unvented cylinder). The Solartwin panel is then connected to that new cylinder via a new feed and expansion tank, which is also required to be installed, and the water it heats then passes from the cylinder and into the combi boiler when a hot tap is turned on. Basically it means the boiler doesn't have to work so hard (thereby using less energy) because the water passing through it is already warm /hot. Unvented cylinders can only be fitted by qualified, registered, installers unless you can comply with part G of building regs.