This panel is deliberately left hidden.

Before committing to a solar thermal system, it is vital to consider a wide range of factors. Besides maximising the efficiency of the appliance, it is equally important to have a sustainable and ecologically sound installation. We have stated how solar thermal systems are ideal for organisation that use and rely on large amounts of hot water (restaurants, hotels, schools, hospitals and larger offices), but it is important to understand that a solar thermal system will not fully replace your existing water heating system and will not provide space heating. The actual percentage of your water heating demand covered by solar thermal will depend on your site and energy consumption habits (though this figure is typically around 30% for commercial sites). A south-facing and unobstructed roof with an inclination of 30° from the horizontal is optimal, though by no means essential as Adveco solar collectors can be installed in a variety of ways: built on roof; built in roof; mounted on walls or on frame construction to achieve inclination on flat roofs.

All areas of the UK are suitable for solar energy technology; however, even minimal shade can greatly reduce a system’s output. If a solar thermal collector suffers significant shade coverage, then the technology will not be applicable and a commercial air source heat pump, such as the Adveco FPi range, may be a preferred option to produce low carbon heat. Assuming the location exhibits no shade issues, Adveco’s application engineers will assess a building’s hot water demand and calculate the number of collectors and size of the storage vessel to correctly size an application.

Solar thermal systems are most productive in the summer months, when there is most sunlight, resulting in the additional need for non-renewable energy sources during the winter months. Despite this sustainability is more than achievable, and Adveco will package the appropriate technology.

The A.O. Smith SGS solar water heater with ITE storage vessel is a perfect example of a sustainable application. The intelligent solar control of the system ensures maximum efficiency. Even with little solar input, the required hot water temperature is guaranteed by the gas burner operating as a back-up system.

As with any water heating system, every application is unique and this demands a bespoke approach Especially when it comes to correctly sizing the solar thermal system, which will ensure the design is optimised for the application and will therefore operate efficiently.

First, a correctly sized system will consider the daily usage and peak demands. Its aim is to serve all peaks from storage, with the size of the peak determining the size of pre-heat. The recovery time for peaks is what ultimately determines number of collectors a building requires.

Second, the design process needs to size usage with available space. So, sizing considers whether the site is flat, pitched or vertical and the type of construction, its direction and shading. Length of pipe run is also important, if collectors are located a considerable distance from the plant the system’s thermal losses could be significantly detrimental to efficient operation.

Together this enables calculation of the Solar Fraction, the total annual heat for hot water compared to total available from solar inputs. To this is then added the details of other energy heaters (typically gas) that are to be used, to fully visualise the completed system.

For buildings already on gas and that rely on large amounts of domestic hot water (DHW) – a large proportion of current commercial UK properties – solar preheat is the preferable option. Depending on the building and energy consumption habits, solar thermal will typically provide around 30% of the hot water demand.

If electrical costs can be offset by adopting solar thermal pre-heat and a gas water heater to meet peak demands, then the numbers can be very favourable. A ten-year return on investment becomes very achievable and the property gains undisputed carbon and cost savings.

Such hybrid approaches are unavoidable for commercial projects seeking a path to low carbon hot water and is the most sensible, practical, and cost-effective option. By using solar thermal with gas after heat, commercial organisations can actively drive sustainability and retain control of operational expenditure for decades to come. With hydrogen policy to be confirmed in 2026, retaining gas in existing commercial buildings keeps options open and future-proofs a building for other emerging heating technologies.