How to buy solar panels Solar water heating installation

Solar roof

Solar panels should be mounted on a south-facing section of your roof

Our experts reveal all you need to know about solar panels - from where to place them, whether you need planning permission and how to maximise their efficiency.

Read on if you're interested in installing solar panels and want to find out more.

Best location for solar panels

  • For maximum efficiency, you need to put your solar panels on a south-facing roof at a 30-degree angle to the horizontal (up to 65 degrees will still work in the UK).
  • Keep the panels away from shadows (from trees, buildings, chimneys, etc).
  • Some panels require regular checks of the unit and connections, or a wipe of the panel glass with mild detergent. Bear in mind how difficult this can be when panels are up on your roof.

Planning permission for solar panels

You won't need planning permission for most domestic solar panels, as long as they respect certain size criteria. But exceptions apply for listed buildings, buildings in conservation areas and World Heritage Sites. 

Contact your council to see whether you need to apply for planning permission for your solar panel. You'll also find more information about planning permission on the Energy Saving Trust's website.

Installing solar panel systems

A solar water heating system involves pipe work, a thermostat and a hot water cylinder. 

You can add solar water heating panels to most existing hot water systems. Although you'll usually need to add an additional cylinder for pre-heated water, or change your existing cylinder for one with a twin coil.

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It's difficult to use a solar water heating system with a combi boiler because these are designed to take cold, mains-pressure water, and solar water heating systems supply warm, low-pressure water. Some new combi boilers accept pre-heated water, so check with the manufacturer.

To find out which boilers are the most reliable, take a look at our boiler reviews.

Maximising solar water heating efficiency

In October 2011, the Energy Saving Trust released the results of its field trials of 88 solar hot water systems. It found that proper installation, householders' behaviour and insulation of the pipes and water tank are all key in improving the performance of a solar hot water system, so you can save the most on your heating bills. 

System performances can be improved if the pumps and timers are set correctly. It also found that in some houses, a lack of insulation on the hot water tank and pipes led to lower performance.

Generally, solar thermal systems worked well and 84% of the people who took part in the trial were either fairly or very happy with their system.

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