Johnstones are proud to offer Solar Thermal as an option for your home or office. We are accredited and approved by MCS. As proof of our status we carry the MCS badge with pride.

napit mcs installer Our official installer certificate number is NAP 16778. Please click here to view our MCS profile.

Solar thermal is a renewable energy system for generating domestic hot water. Solar thermal water heating works in a similar way to leaving a hosepipe in the sun. Solar thermal generates renewable heated water using solar panels (known as “collectors”) fitted at an optimal angle on a roof. Solar heat warms fluid, usually anti-freeze, in the collectors and this is then pumped to heat water stored in a hot water cylinder. A boiler or immersion heater tops up the water to the temperature set by the cylinder's thermostat (>60°C)


  • Solar thermal should work all year round during the day but consumers will probably need to heat the water further in winter months, using a boiler or immersion heater.
  • Solar thermal can save on fuel bills
  • Solar thermal should be eligible for renewable heat incentives
  • Solar thermal can cost a lot less to install than other microgeneration technologies
  • Solar thermal does not cost more than £5000.


Energy output of solar thermal relates to latitude and levels of direct sunlight. Solar thermal might provide up to 70 percent of the average house’s hot water needs, depending on the amount of hot water used and levels of energy efficiency in place. However, the Energy Saving Trust information is that a more accurate figure is lower than this.

RHI tariff payments will start for homes alongside the Green Deal from 2012 to allow a more whole-house approach to heat production and energy saving.

In the meantime, up to 25,000 installations from July will be supported by a “RHI Premium Payment” to help people cover the purchase price of green heating systems.

Those taking up the Premium will then be eligible for a RHI tariff from October next year when the Green Deal begins, as will anyone else who has had eligible equipment installed from July 2009.

For commercial, industrial and community heating we have RHI tariffs starting this year.


At micro-level (<45kW), there are MCS standards for solar thermal for installer companies and products. MCS installers and products are likely to be mandatory for RHI and Premium Payments and MCS installer companies must belong to a consumer code of practice. At the moment there is only one, the REAL Assurance Code .

See MCS installer companies and MCS products @

For the consumer code linked to MCS see

At the moment there is one other certification scheme considered ‘equivalent’ to MCS for solar thermal, Solar Keymark (see further details on the MCS website). Solar Keymark products are considered equivalent to MCS products for all UK support. They must be installed by MCS installers, to be eligible for incentives.


Getting planning permission can be a barrier to householders wishing to install microgeneration technologies. In England and Scotland, changes to permitted development rights were introduced on 6th April 2008 and 12th March 2009 and applied to most solar thermal.


MCS installer companies are able to give consumers advice on specific products and impartial advice on the suitability of individual technologies. They are required under MCS standards to give accurate written estimates of likely energy outputs from a technology.