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Solar Factsheet
Why Renewable Energy?
Climate change is a real threat to our future, and a major cause is the use of fossil fuels to power our homes and businesses. Renewable energy, combined with energy efficiency, offers a viable and potent solution to countering the effects of global warming.
By installing a solar hot water system, you will be making a major personal contribution to the wellbeing of future generations and you will also benefit from lower fuel bills.
Solar Energy in UK
In the UK we receive vast amounts of solar energy with the average amount of energy received in a year being as much as 60% of that received on the equator. This radiation is similar to the output of 1,000 power stations. In central and southern England we receive around 1100kWh of solar radiation energy per square metre, per year. 
Typically modern active solar heating systems convert 40-50% of this energy into useful heated water, that’s 440-550kWh per m² of free energy.
Generally, one can expect for a modern solar system to provide around half your hot water requirements through the year. Not only does that reduce your bills but by replacing fossil fuels, each system prevents around 250kgs of carbon dioxide from being released into the atmosphere, annually.
Is your house suitable?
Solar collectors work best when they face south and are inclined at an angle of 30-40 degrees. However fairly large variations can be tolerated with relatively little degradation in performance. For example, a southwest facing roof angled at 60° would still operate at greater than 90% of its potential. Systems can also be supplied with two collectors, one facing east and the other west.
Typically, a new ‘dual-coil’ hot water cylinder is fitted, which incorporates a solar heat exchanger. The system remains connected to your existing boiler for back-up, so you never run out of hot water.
Standard ‘open-vented’ cylinders are the most common, but mains-pressure systems are readily available. Solar hot water systems may even be used with ‘combi’ boilers (please ask for details).
System Sizing
For advice on system sizing, see our related blog post.
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Types of collector
There are two main types of solar collector used for domestic hot water:
- Flat plate.
- Evacuated tubes.
There are also some more specialised designs such as:
Unglazed collectors - used for swimming pools
Focussing collectors - - for high temperature systems to
generate steam.
Of the two main types employed in solar water heating systems, evacuated tube collectors offer higher efficiencies, typically 20% higher than flat plate types. There are however, some significant advantages of using a flat plate design:
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Low cost - flat plate systems typically offer significant cost savings for similar energy output.
- Low Maintenance- The evacuated tubes lose their effectiveness if the vacuum collapses so regular checks are required.
Evacuated tube collectors offer advantages where the roof orientation is poor or there is a lack of roof-space. Some designs can be mounted horizontally on a flat roof or on a vertical wall.
Flat plate collectors may be mounted on top of the roof tiles or integrated into the roof. Normally roof integrated collectors would be used in a new-build project. Support frames are available for flat roof mounting also.
The Drain-back System
Where practical, we favour the drain-back system. It deals with the potential boiling and freezing issues with elegant simplicity. See our website for more information.
How Much Will It Cost?
Professionally installed systems are available from £2500. Many factors will influence the cost, including the system type, size and complexity. If you prefer, we can also supply kits for you to install. This option is, of course, cheaper but you need a certain level of skill. Visit our website to buy kits or components online.
What Next?
If you are considering having a system installed, check out our website for more information. You can get an instant, online quote, arrange a survey or buy products online. If you choose to book a survey, be assured we do not employ ‘high pressure sales’ tactics, we will, however, provide a thorough inspection of your property and a comprehensive report and quotation. Feel free to ask to speak to a past customer in your area. Our customers are hugely enthusiastic about their systems and will be more than happy to tell you of their experience with Solaris.
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