Solar panels use PV (photovoltaic) cells that convert sunlight into electricity. Assessing whether your property’s roof is in a good position to generate solar power is essential before committing to installing any solar energy technology.

Roof position

Your roof will need to face south or within 90 degrees of south and should be in a relatively sunny position. If your roof is overshadowed for part of the day then this will generate less power. As well as this your roof needs to be structurally sound and in a fit enough state to be able to support the weight of the panels.
The Energy Saving Trust advises that your roof should be at a pitched angle of between 30 and 50 degrees from the horizontal for best performance. If you have a flat roof, panels can be attached to a frame tilted at the optimum angle.

Housing Energy Advisor suggests that you use free online solar angle calculator to calculate the best angle for each month of the year and then work out an average. Alternatively, you could make the most of the summer sunshine by calculating the optimum angle for June and setting your panels in that position. This would be the best option if you want to produce as much energy as possible to sell back to the national grid. A third option would be to set your panels at the optimum angle for the winter months. In this scenario, it would be likely that you would still be able to produce enough energy for the summer months, but this will give the additional benefit of reducing the amount of energy you need to buy in the winter. Unfortunately this would also reduce the amount of surplus energy you’ll be able to sell.

Weather conditions

Solar energy systems will produce energy all year round, but will produce significantly less during the winter months. Solar panels can still generate energy even on a cloudy day and the Energy Saving Trust even estimates that a system can still generate up to a 1/3 of the energy on a cloudy day that would usually be produced on a sunny day.

Regular amounts of rainfall are essential to the efficient operation of solar panels, as this cleans off any dust and dirt that could settle on them and could prevent the sun’s rays from being efficiently harnessed. This also helps to keep the panels cool, which benefits the panels as they operate with greater efficiency at lower temperatures.

Guest Article by Amy Catlow.