Solar Thermal


Solar Thermal systems, like Solar PV systems, are suitable for both urban and rural locations and are adaptable to almost any building which has sufficient exposure to light. To tell if solar water heating is right for you there are a few key questions to consider:

  • Do you have a sunny place to put solar panels?
    You’ll need around 5 square metres of roof space which ideally faces South and receives direct sunlight for the main part of the day; or If this isn’t possible you can install a East or West facing system and still get great production. Typically panels are mounted on a pitched roof however; they can also be mounted at ground level or mounted on a flat roof. Ideally they should receive direct sunlight without shade. For the best results they should be angled between 20 and 60 degrees from horizontal (most pitched roofs fall within this bracket).
  • Do you have space for a larger, or an extra, hot water cylinder?
    Another consideration you have to bear mind is allocating space for a larger, or another, hot water cylinder in your home. When installing you may need to replace the existing cylinder you have for one with a solar heating coil, or have an additional cylinder just for your solar heating system.
  • Is your boiler compatible with Solar Thermal?
    Most conventional boilers and heating systems are compatible with solar water heating, including combi-boiler systems.
  • Do you need planning permission?
    In England, the installation of a Solar Thermal system is normally considered Permitted Development at both domestic and commercial levels meaning you will generally not need to apply for planning permission. There are some exceptions to this however such as Listed Buildings or some Conservation areas. At Duncan we have a planning advisor on hand. We can assist you with any Planning Applications or undertake the application process on your behalf. Up-to-date guidance is available on the Government’s Planning Portal

Designing a Solar Thermal system for your property

With over 15 years experience in design and installation of solar thermal systems we can provide a system tailored to the needs of your site. We have provided solar thermal installations integrated into new build properties, installed on-roof as a retro-fit system as a ground/flat-roof mounted system, as well as commercial large scale swimming pool systems.

A Solar Thermal system can be used to provide hot water for your household or business needs (shower, sinks, washing machine etc…) or for a more specific purpose such as heating a swimming pool, depending on the roof area and space available for a storage tank.

In addition to designing a solar thermal system we can also provide for the design, installation or upgrading of your existing or new plumbing and heating systems. If you are engaging in a larger project we can provide our sole services or we can work alongside your existing developer/builder.

One question that many of our customers ask is whether an installation is suitable for their roof, taking into consideration the pitch, the tiles and the additional weight. Our solar panels weigh approx 40kg however the size of the modules mean the weight is well dispersed. The system will be secured to the roof with high quality, European designed and manufactured, aluminium fittings and all of our work is undertaken within strict guidance of building regulation. Providing that your roof is in suitable condition, (and most are), a thermal system can be fit to whatever roof type you have. The installation itself will not cause any damage to your roof’s weather proofing and most cases the installation of a thermal system will not require the removal of any tiles. With each job where necessary we will always consult with a structural engineer before undertaking our work.

Solar Thermal: Hot Water Production and Energy Savings

The Energy Savings Trust says solar thermal panels will ‘provide about a third of your hot water needs’, the Centre for Alternative Technology puts it at about 50%, and additional research suggests a 60-70% annual hot water usage heated by the sun. The reality will depend on a variety of factors:

  • How much interest you take in how the system works and adapt to make the most of the free hot water (ie having showers in the evening rather than the morning).
  • The size of your cylinder. Many cylinders only hold enough water for less than a day’s supply of hot water, so a day or two of cloud and rain will mean you have to turn on the boiler or immersion heater. That is why we often recommend upgrading to a cylinder that ensures you can take full advantage of the free, clean energy output from your Solar Thermal system
  • How you programme your boiler. If your control panel does not allow you to programme the hot water and central heating separately, you may not get the maximum benefit from the solar thermal panels when the heating is turned on. By only boosting the hot water once the sun has gone down you maximise the solar heating.

In the UK the average domestic consumption is approximately 4,800 kW/h for a 3-4 bedroom household. A smaller than average household is taken arbitrarily to be 3,000 kW/h and a larger than average household to be 7,000 kW/h. What this means is that for most domestic properties you can expect a standard solar Thermal System to help reduce your energy consumption and costs between 20-40%.

Speak to one of our friendly advisors. Call us on 01423 359 600 or Make an enquiry