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solar PV
solar thermal
windEvery day the Earth receives more energy from the Sun than the whole world consumes in a year. The technology to use this energy is now well developed with a large choice of equipment to suit all households and small businesses in the UK.
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- Solar Thermal produces hot water.
- No electricity is produced - a completely different system called Photovoltaics or Solar PV is needed to produce electricity.
- Solar Thermal systems are typically cheaper than PV and becoming commonplace. There are over 70,000 installations of solar thermal in the UK.
Uses
Solar thermal systems are used for:
- Warming a significant % of your hot water needs
- Can be used for central heating systems, but this application is typically less compelling as most heating is needed in the winter when there is less solar energy available in the UK
- Heating swimming pools, where the economic case and results can be very positive
How does Solar Thermal work?
Solar water heating uses heat from the sun to warm up liquid pumped through a panel on your roof - these are called Solar panels or collectors.
Typically, this solar heated water will then be used to heat the water in your new hot water cylinder. The water then flows from your hot taps as usual - being heated up further (if/as necessary) by your normal hot water heating system.
A pump and water system connects the solar collectors and the cylinder.
The benefits - why install?
- Solar water heating can provide almost all of your hot water during the summer months and 50 - 70% across the whole year.
- The average domestic system reduces C02 by around 350 - 400kg per year, depending on the fuel replaced.
- One square metre of solar collector/panels on your roof can typically provide the equivalent hot water heating as more than 100 litres of heating oil. With oil and gas prices threatening to rise over coming years, the hard economic benefits are set to improve further.
- The value of your home will be enhanced by a quality installed solar thermal system. The arrival of Energy Performance Certificates will reinforce this.
- We all need to do our part, and it's very satisfying to have water heated for free using a freely available and sustainable natural resource!
Is it suitable for my home?
Factors that need to be considered are typically:
- South-East to South-West facing roof space that receives direct sunlight throughout the day for domestic use; for swimming pools, similarly aligned space is needed near the pool
- The type of hot water system you have - combination boilers (where water is heated on demand) are less suitable for Solar Thermal systems although suitable systems do now exist
- The space available to add a 2nd hot water cylinder or most likely replace the existing single coil cylinder with a larger dual coil one
An accredited installer or supplier will help you plan the best system for your circumstances and budget.
What makes up a Solar Thermal System?
For domestic hot water there are three main components:
- Solar panels or 'collectors' are fitted to your roof. They collect heat from the sun's radiation.
- Plumbing and electrics to transfer the heat to the hot water cylinder effectively.
- Hot water cylinder - stores the hot water that is heated during the day and supplies it for use later.
Different designs used
Depending on your circumstances and the system installed, there may be certain differences in your system. Examples are:
- Solar collectors come in 2 distinct types:
o Flat plate - most robust, cheapest, but less efficient and so more dependent on a southerly aspect and requiring a greater collector area.
o Evacuated or Vacuum tubes, made up of many cylindrical tubes - typically more expensive but more efficient per square metre and tolerant of less than perfect southerly aspect. - Closed or Open systems
o Closed systems are most popular, where the liquid warmed by the sun is used to heat the water in a cylinder using a coil (like a standard heating/hot water system).
o Open systems are used less commonly in the UK (partly due to problems with freezing, although some systems do overcome this), where the water heated by the sun is directly fed into a hot water cylinder. - One cylinder or two? New or existing?
o Depending on requirements and existing situation, a new larger cylinder (with dual coils) or a 2nd cylinder will most likely be required. It is rare for no changes to the cylinder to be suitable (and only in some Open systems).
Installation, maintenance and costs
The typical cost for a domestic system is £3,000 - £4,500 (see table below).
Installation may take one to three days for a skilled installer.
Solar water heating systems generally come with a 5-10 year warranty and require little maintenance. A yearly check by the householder and a more detailed check by a professional installer every 3-5 years should be sufficient (consult your system supplier for exact maintenance requirements).
No of householders/Area of solar panels/Vol of Storage Cylinder/Indicative Cost
2-3 3 - 4 sq m 150 - 200 litres £2,500 - £3,500
4-5 4 - 6 sq m 200 - 300 litres £3,000 - £4,500
6-7 6 - 8 sq m 300 - 400 litres £3,500 - £4,500
Grants are available - £400 or to 30% of overall maximum cost.
Where can I find out more?
The DTI funded low carbon buildings programme provides grants to help with the costs of installing solar water heating technologies.
To be eligible for a grant you will need to use a certified installer and products.
Or visit the following sites:
Visit: Energy Saving Trust
Visit: Centre for Alternative Energy
Visit: Look for Ourpower Pioneers in the Ourpower Community who have fitted Solar Thermal systems near you so you can ask and read about their experiences. Then use the Ourpower Directory to find local installers and suppliers - reading about what they can offer and what they have done, before asking a number to consider your situation and to quote. Always, get at least 2 quotes - more if possible.
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