How it works
Solar hot water heating systems use Solar Collector Panels, either “flat-plate” or “evacuated tube” panels to harness radiated energy from the sun.
Flat plate collectors are fitted the structure of the roof in flush glazed frames. Evacuated tube collectors, whilst aesthetically more prominent, are sometimes more efficient at non-optimum roof-angles.
Hot water generation systems consist of three main components:
The heat transfer system uses the collected heat to heat water. A hot water cylinder stores the hot water that is heated during the day and supplies it for use later.
The majority of installations use a heat transfer fluid - glycol antifreeze, which protects the external parts of the system in the winter. The heated fluid is transported into a coil within your hot water tank and heats up the water fed from the mains supply.
Like Solar PV Panels, Solar Hot-Water Panels are best fitted to a south-facing roof aspect as possible. If the roof ridge runs north/south it may be possible to position a collector panel on each face of your roof – an 'East/West' system - one panel set uses morning sun and the others use the afternoon sun.
Cost & Considerations
As with normal hot water cylinders, a standard solar hot water system is not designed to work in conjunction with your central heating radiators or under floor heating systems - they can only heat your water for shower, bath and kitchen use.
You may need space for a larger, or an extra, hot water cylinder. You may need to replace the existing cylinder or add a dedicated cylinder with a solar heating coil.
However, most conventional boiler and hot water cylinder systems are compatible with solar water heating. If your boiler is a combination (“Combi”) boiler and you don't currently have a hot water tank then a solar hot water system may not be compatible.
In any event, we will be able to advise your product and cost options during our preliminary survey.
The typical installation cost for a domestic system is £3,000 - £5,000. VAT is charged at 5%
Most systems come with a 10-year warranty and require very little maintenance. An annual check by the householder and a more detailed check by a registered installer every 3-5 years should be sufficient (our project summary notes always detail exact maintenance requirements by system or installer).
The average family home uses 4000KwH per annum and the optimum FIT rate using a 4kWp system covers around 32m2 of roof space or installation.
Permitted Development Rights (PDR) for domestic microgeneration technologies introduced on 6th April 2008 have lifted the requirements for planning permission for most solar hot water installations.
Roof mounted and stand-alone systems can now be installed in most dwellings, as long as they respect certain size criteria. Listed Buildings, buildings in Conservation Areas and World Heritage Sites do however, require planning approval. In most cases, we have found that installations can be made to these restricted areas if the system is installed out of sight of the front of buildings where the impact on surroundings is not a consideration.
In any event, our service includes a check on your PDR and we undertake a free Local Authority “Pre-Planning Enquiry” if there is any doubt about your proposed installation.