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Frequently Asked Questions

Solatherm Hot Water Heating

How do I know how much heat the solar panels provide?
The output of 2 panels with a total area of 4 sq. m is about 1600 kWh pa. in the southern parts of the UK.

Where should the Solatherm panels be positioned?
The solar panels are placed on a South to South West facing sloping roof. They should be positioned at an angle between 20 to 50 deg. to the horizontal. That is most roof. Triangular frame is required to support the panels on a flat roof.

Can the solar panels be used to heat the central heating or the underfloor heating? There is not enough heat available from the solar panels when the heat is needed most. Say in the evening and on cloudy cold days. Solatherm would be more suitable with underfloor heating rather than radiators. The heat gained from the solar panels is stored at low temperature in the screeded floor.

Do I need a boiler as well as solar panels?
The solar panels may give adequate hot water heating in the summer and will help to pre-heat the water in winter. The boiler will then bring the hot water to the required temperature. Thus solar technology in the UK will provide anything between 50 to 70% of the hot water energy requirement. This also depends on your location in the UK.

Is there VAT on installing Solatherm?
For systems installed by specialist the VAT is 5%. You pay standard rate VAT on material if you self-install. You can claim the VAT if the installation is part of a new house.

Are Solatherm panels as effective as evacuated tube type solar panels?
Solatherm panels are 95% as effective as evacuated tubes. Yet they are a fraction of the price, reliable and long lasting.

 

TopTank Unvented Cylinders

What does unvented mean?
Traditional cylinders are connected to a tank in the loft to act as vent for when the water in the cylinder is heated and expands. Modern unvented cylinders use an expansion vessel instead of the open tank in the loft. The pressure in the cylinder remains at mains pressure and the flow from the hot tap and shower is much greater.

Can I install the tank on the ground floor or in the garage?
Toptank can be installed on any floor in the property. Mains pressure hot water cylinder has 6 to 9 times the pressure of an open tank in the loft pressurising the old copper cylinder.

What is the water mains pressure in my area?
It should be around 3 bar but varies greatly from one part of the UK to another. Your local water company should supply you with this information or OFWAT. There is still some residual resistance by these companies to the installation of unvented mains pressure cylinders. This resistance is vanishing slowly.

 

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