To get an idea of the likely costs and payback from various different solar PV system sizes on your roof please have a play around with our solar calculator tool.

To specify the location of your proposed installation simply click on the 'change our assumptions button' and type in your postcode. If you have a particularly steep or shallow roof, or want to alter the assumptions made about the average inflation rate and energy price increase used to calculate the financial performance you may also alter these settings here.

Please note that we use a slightly different method for calculating performance and long term performance in our actual quotes so your final figures may vary slightly from those shown in this calculator tool.