What is it?
Hot water from sunlight. Circulating liquid in tubes or panels on the roof catches the heat even from diffuse daylight and heats up rapidly, and runs through a coil in your cylinder, heating the water just like a boiler does. The cylinder is in fact a special design with two coils so that you can use your existing boiler when you need to. You could have an immersion heater for backup, as well as (or instead of) the boiler.
Will it work here?
Surprisingly, yes. Even cloudy days provide a fair bit of heat and most households can expect to have 50-70% of their annual hot water provided by solar.
Can I run my Central Heating this way?
In principle you could but it would mean a large hot water store and a big array of panels, and isn’t generally economic at present. Some systems which have sizeable hot water stores already (such as wood-fired central heating) can usefully have the solar component included, though, and this will change the financial aspects considerably for the better.
But is Hot Water economically sensible on its own?
Yes, up to a point. With current energy prices pay back may be around 5-10 years, but those prices are only going upwards, and probably pretty steeply.
Should I wait for Solar to get cheaper?
There isn’t much chance of a worthwhile fall in prices – it’s a mature technology (unlike solar electricity, also known as photovoltaic or PV, where costs are likely to fall significantly in the near future). One good thing, though, is that the present VAT rate on solar heating panels installations is just 5%.
What about planning?
In general there is no problem. Unlike PV installations which may need a great many roof panels, most domestic solar heating systems use just two or three. Many Councils have a positive attitude to solar thermal and unless the proposed installation is very intrusive and/or in a very special location then there shouldn’t be an issue. You need to let them know what you intend to do, either by letter or more easily by filling in a simple form on the Council’s website.
What about grants?
There are some but they’re small, there’s a lot of competition and you have to use a listed supplier and contractor. This usually means paying a lot more to start with, as in the early days it was quite difficult to get accredited as a contractor for the various Government schemes and those who did manage it have made the most of their status. The list of accredited suppliers is growing, however, and more small local concerns are getting through the official process.
Go on then, what will it cost?
It depends, of course, on the size and layout of your house and your hot water needs: but the range is £3-6K for most properties. It’s cheaper to include solar when a house is first built, naturally.
Are there better ways to spend my money to make my house cheaper to heat?
Yes. Insulating properly is far and away the best and most cost-effective work you can do. If you’re building from new or making major renovations then ground or air source heat pumps and underfloor heating have a lot to recommend them. When replacing your boiler, choosing an efficient and well-manufactured unit is hugely important. Changing the boiler fuel to wood, if you have a good source, will also reduce your carbon footprint significantly and reduce fuel costs. After that, though, solar heating is the simplest and most useful improvement you could make.
Where can I find out more?
There’s a lot of information on the Internet, though it can be confusing and contradictory. The advice and information available from Councils and agencies is pretty thin and partial, though occasionally useful, and tends to reflect whatever schemes are in vogue at the moment. The Centre for Alternative Technology at Machynlleth sells books on all aspects of renewable energy systems, and runs courses if you are dedicated enough.
Otherwise, a specialist local contractor like West Wales Heating Ltd will be pleased to discuss your needs in general and work out an outline installation scheme for free – detailed planning and specification may cost a little, but you should see that as part of the overall cost of the job.