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Solar Thermal Systems | FAQs

How does it work?

A solar thermal system captures the Sun’s energy and uses it to generate hot water through solar panels (collectors) fitted at an optimal angle on a roof or ground mount. Solar heat warms the fluid in the collectors, usually anti-freeze, and this is then pumped to heat water stored in a hot water cylinder. An immersion heater or boiler then tops up the water to the required temperature, as set by the cylinder's thermostat.

How much hot water will it generate?

In a family home (south facing roof, 30 degree pitch), a Solar Thermal system will provide you with up to 60 – 70% of your water heating for free each year. During the summer months the system could provide a standard household with nearly all its hot water requirements and during the winter, around half.

How much will I save?

Savings on energy bills varies depending on the amount of hot water you use and the type of fuel displaced. Savings are higher if electricity or oil is used to heat water.

Typical carbon savings are around 230kgCO2/year when replacing gas and 510kgCO2/year when replacing electric immersion heating.

What are the financial returns?

Commercial installations are eligible for the government’s Renewable Heat Incentive (RHI), see our financial rewards page for more information. This scheme was launched in December 2011, the domestic RHI is due to be launched in spring 2014.

Domestic systems currently receive a one off RHPP payment for an installation. This is currently £300.

Can solar thermal be used for heating Swimming Pools?

Yes, solar thermal is often installed as part of a swimming pool heating system, providing the pool is enclosed.

Is it suitable for commercial installations?

Yes, we install commercial scale solar thermal installations such as Coventry University.

Can it be used for space heating?

Systems can be linked to space heating, but generally due to the temperature of the water this is not worthwhile. However, solar thermal can be used as a method of pre heating water when integrated into another system ie Heat Pump.

What kind of collector should I use?

There are two types, flat panel and evacuated tube. Both are efficient systems so the choice is often on aesthetics, location and personal preference.

Is my roof suitable?

We can fit solar thermal systems to all types of roof, flat or pitched, or as a ground mounted system. The location must receive direct sunlight for the main part of the day, so the optimal direction is south or near south facing.

How much space is required?

For a standard domestic installation, 5m square would be suitable.

Is your current boiler compatible with solar water heating?

Most conventional boiler and hot water cylinder systems are compatible with solar water heating. But if your boiler is a combination boiler and you don't currently have a hot water tank, a solar hot water system may not be compatible. We will advise you on this.

What equipment do you install?

We install three main components for domestic use:

  • Solar Panels to collect heat from daylight to convert into solar fluid
  • A Pump station and pipework to circulate the solar fluid
  • A Hot water cylinder where the water is heated and stored

It may be possible to use your existing hot water tank, or we may need to fit a new one.

How long does it take to install?

A standard domestic installation will take two days, depending on your requirements, commercial installations depend on size of system. Weather conditions can affect installation times, as some work takes place outside your home.

Do I need planning permission?

Commercial and domestic systems do not generally require planning permission as they come under "permitted development" rules, if the panels do not protrude more than 200mm from the roof planning is not required. However, ground mounted systems will require planning permissions and some local authorities still require additional details to allow you to fit a Solar Thermal system, especially in conservation areas or on listed buildings.

Always check with your local authority about planning issues before you have a system installed. Obtaining retrospective planning permission can be difficult and costly.

Are there any minimal structural requirements?

We will assess the suitability of roof or ground area and may recommend a full structural assessment by a surveyor. The roof must be in good condition as the solar thermal array is designed to last 20+ years. Any roof repairs should be carried out before installation of solar array.

How long do the systems last?

Solar Thermal Systems will typically last up to 25 years or even longer, depending on the manufacturer.

Are there any maintenance or servicing requirements?

A monthly visual check is advisable ensuring that the panels are kept relatively clean and that shade from trees or other obstructions has not become a problem. It is also advised that the integrity of the glycol within the system be checked and tested every 2-3 years. More details can be provided on request.

How do I use the system most efficiently?

To obtain maximum benefit from a Solar Thermal system, continue to use your domestic hot water as normal.

During the months of the year when additional heating is necessary, you should set your existing heating to come on towards the end of the day. This will allow the Solar Thermal system to put as much heat into the domestic hot water cylinder as possible.