FAQs – Solar Hot Water

How does Solar Hot Water (SHW) work?

SHW systems use energy from the sun to warm fluid circulating in Solar thermal panels, and then transfer this heat to the hot water in your cylinder. They work alongside your conventional water heater and can heat the water to 60-70 degrees centigrade in summer months. The technology is well developed, with two major types being used for general domestic & commercial water heating. These are either, the evacuated tube type or flat plate collector. Our Solar energy systems will provide between 40-70% of your hot water needs, 40% in winter and 70% in summer, averaging out throughout the year at 55%. Thus saving you money, aswell as reducing your properties CO2 emissions by between 0.4-0.75 tonnes per year. For a more detailed explanation of how the system works, please see our Solar Hot Water page.

What is the difference between Solar PV and Solar Thermal?

Solar PV is a technology that uses the sun’s energy to create electricity. Solar thermal is a technology that uses the power of the sun to heat water. Solar thermal systems only require daylight to operate and a correctly installed system works all year round – even when it’s cloudy. In fact, the system will provide you with hot water for approx 70-80% of the year (Reduced amount of daylight hours during the winter reduces production of heat energy).

What is the RHI and can I claim if for Solar Hot Water panels?

The RHI is the Renewable Heat Incentive – this is a government-backed scheme that pays home owners, private landlords, self-builders and social landlords for the generation of heat from renewable energy sources. By installing a Sustainable Energy Engineering Solar Thermal system you would be eligible to receive RHI payments. Payments are guaranteed for seven years and are TAX FREE and INDEX LINKED.

How do I apply for the RHI?

You can apply online at the Ofgem website. You will need your MCS certificate and your Green Deal Assessment including the EPC (Energy Performance Certificate) – all of which we provide on completion of a system. The application process is relatively straight forward, however , if you experience any problems we are more than happy to help with the application.

What is a Green Deal Assessment (GDA) and why do I need one?

A Green Deal Assessment (GDA) or Green Deal Advice Report (GDAR) consists of an EPC and an Occupancy Assessment of your home. Which together show how energy efficient your home is and how you use your energy. Wer have in-house Green Deal Assessors who can visit your home to carry out this assessment. In order to be eligible to receive the RHI payments, your property needs to have had a GDA and have loft and cavity wall insulation if identified on the report.

Will I need planning permission?

Generally no. Both Solar Thermal and Solar PV systems are classed as ‘permitted developments’ so do not require planning permission. As long as the solar panels do not protrude more than 200 millimeters perpendicularly above the inclination of the roof slope and do not go higher than the ridge of the roof. The only exception is if your property is a listed building, or is in a conservation area, in which case you will need to consult with your council planning department. However, we have installed numerous systems in conservation areas, where planners generally prefer the more aesthetically appealing black framed panels.

What guarantees will I receive?

Our solar thermal panels come with a 10 year manufacturers warranty and we guarantee the workmanship of our systems for 10 years, which is also backed by the Independent Warranty Association (IWA) scheme, to give you increased peace of mind.

Will solar thermal panels work in winter?

Yes we still get some energy from the sun in winter that will contribute to the heating of your hot water, meaning your main boiler, whether this is biomass, electric, gas or oil, biomasshowever they will unlikely be able to satisfy all of your heating needs at this time of year alone. In winter, your heating demand will be higher but there is less solar energy for the panels to absorb, and so it should likely be combined with another technology to satisfy all of your heating needs.

Does it work all year round?

From March to September solar energy could provide all your hot water but will only partly heat the water during the winter months, when your boiler will need to be used to bring it up to temperature. Most homes will need to replace their current hot water cylinder, with a dual coil solar model.

Is solar water heating a viable alternative to gas or electricity?

Solar should not be seen as an alternative to gas or electricity, but rather as a supplement. Solar cannot totally replace the need for gas or electric heating as there are sometimes days when there is little sunlight. When averaged over a year, a correctly-sized solar system can provide 60%-70% of a householdʼs hot water needs. Providing more than this is unadvisable, as too much heat will be produced in the summer. The hot water system can easily be automated so hot water is guaranteed regardless of sunlight levels.

How much will it cost?

A standard domestic system for a 3 bedroom home with 3 occupants will cost between £3500 and £5000 depending on the specific requirements. We can provide a free quotation after visiting your property and completing a free survey.

What does the price depend on?

Prices vary, depending on the number of panels that are fitted and the type of cylinder that is installed.

How long will it take to recoup my investment?

Solar collectors are much more affordable than many other hot water heaters. For a household of four, the price of a full system may not be too much more than a new electric or gas system. Depending on your location (solar levels) and current hot water usage, the annual electricity or gas saving will differ. However in a normal household that spends 25% of its electricity bill on hot water heating. You will definitely make savings during the life of the solar hot water heater.

What maintenance of the solar collector is required?

Under normal circumstances no maintenance of the system is required. Due to the shape of the tubes regular rainfall and wind should keep the tubes clean. Should a tube break it should be replaced. Solar collectors can operate with several broken tubes however the efficiency will be reduced slightly.

How do the panels connect to my existing hot water cylinder or tank?

Your hot water cylinder will be replaced with a high efficiency twin coil cylinder. The solar panel will heat the bottom of the tank and your boiler will top up the heat if required.

Can I use it with a combi boiler?

Generally yes, modern solar ready combination boilers can take pre-heated water directly but older models will require installation of a mixer valve to limit the temperature of the water on the inlet to the boiler to about 40°C. Grant make a purpose made valve system for this application, but there must also be room to install a hot water cylinder . The valve allows the Solar Thermal system to by-pass the boiler in summer months, and to pre-heat the cold feed to the boiler at colder times.

Can solar collectors be used for a large scale hot water production?

Yes. Solar collectors can be connected in series or parallel to provide large-scale hot water production for a commercial setting such as a school, hotel or office building. There is really no limit to the size of the system, however collectors must be installed in banks of no more than 150 tubes (in series), otherwise the water may boil. See the examples in our Solar Hot Water section.

Can a solar thermal system be used to heat a swimming pool?

Yes, swimming pools are an ideal application for solar thermal systems (especially for outside pools) because they tend to be used more during sunny weather. The relatively low temperature required by a swimming pool means that the efficiency of the system is much higher.