Installation of Solar Thermal Panels
Because solar water heating systems are now so popular there are plenty of knowledgeable tradesmen qualified to install your system. The installer must be accredited by the Microgeneration Certification Scheme (MCS) for you to qualify for the Renewable Heat Incentive and RHPP.
You will need to decide whether to use flat collectors, which can be fitted more flush with the roof, or evacuated tubes, which are more efficient. For more details on the different types of collectors take a look at How do solar water heating systems work?
You will need to ensure the following:
- Location – You will need suitable space (around 5m2) on a south facing roof which is in direct sunlight for the vast majority of the day. Ideally the collectors should be angled at a 30 degree angle of incidence. The collectors can be fitted to a flat roof if they are attached to a frame to allow them to be angled correctly.
- Roof durability – You will need to check with your installer that the installation will not damage the integrity of your roof and that your roof is strong enough to bear the collectors as they can be heavy.
- Space for a solar cylinder – A large hot water cylinder will be required to store your heated water; this is typically between 30 and 60 litres. This can either be a dedicated solar cylinder or it might be possible to add a solar heating coil to your existing cylinder if it is large enough.
- Compatibility with your boiler – Most boilers are compatible, however a Combi (Combination) boiler doesn’t normally have a hot water cylinder and therefore may not be compatible.
- Planning Permission – On the whole you will not need planning permission if the collectors aren’t more than 20cm taller than your roof. However, if you live in a Listed Building, a building in a Conservation Area or a World Heritage Site, it is a good idea to consult your local authority.
Time to install
The time it takes to install a solar thermal system will depend on the size of the system and the roof’s integrity, as well as how the system is going to link into the existing water system.
We only recommend installers that are MCS accredited: Always use an MCS accredited installer. Only MCS accredited installers are able to sign off installations that will comply with the government’s Renewable Heat Incentive scheme.
- Can I use solar thermal panels with an existing combi boiler?
- Yes, there are specially designed systems that work very well with most combi boilers. It will requires the installation of a storage cylinder and possibly some enhanced controls for the boiler.
- Does my roof need to face south to be suitable for solar thermal?
- A south facing roofs at a 30° angle offers the best annual output for a solar thermal system. However, east or west facing roofs can function very well as the available solar radiation only reduces by about 20% in these orientations. The size of the panels can be increased to compensate for this reduction.
- Do my solar panels need to be MCS approved?
- In order to be eligible for the RHI and RHI Premium Payment the panels need MCS approval. There are also other accreditation schemes such as the Solar Keymark.
- How are solar thermal panels fixed to the roof?
- If you have a typical roof, solar thermal panels are usually fixed to your roof using rigid stainless steel brackets that are fixed directly to your roof rafters. The only roof type that can't have solar thermal panels fitted is a thatched roof.
- What is the heat output of a solar thermal system in kWh?
- Outputs from a domestic solar water heating system typically range from 1000 - 2500kWh per year.
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