Feed In Tariff Calculator

The below calculator will give an accurate estimate of the savings/income from the proposed Feed In Tariff, based on your system size and anticipated usage.

Please enter a proposed system size in the first box, then change any of the following default values if required, before displaying the results with one of the two buttons.

PV Power [kW] – This is the peak power output of your proposed system. 1kW requires 7-8m2 of roof space and costs £5000-£5500. You can estimate your system size using our domestic calculator.

Annual Output [kWh/kW] – This is the estimated annual output in kWh from 1kW of solar PV. We normally see 1000kWh/kW in South West England, hence you can leave this as the default if you live in this region. However, you may wish to reduce this if the aspect is not perfect (ie. if you are facing east or west then this should be reduced by 15-20%)

Cost Per kW Installed [£/kW] – The default for this is £5500 and this can be used for rough calculations. However, this varies for different properties depending on location, access, roof condition, etc. If you already have a quote from us, then please divide the total amount by the kW size and enter the result in this box.

Import Tariff [p/kWh] – This is the price you pay for importing electricity from your supplier (normally between 10-17p/kWh)

Personal Usage [%] – This is an estimate of how much of your generated power you will use yourself, rather than exporting it. If you are normally at home during the day this is likely to be 75-100%. If you are only at home during the day at weekends then this is probably 30-50%. This percentage changes the calculation because it affects the amount you export and your savings on non imported electricity.

Annual Summary button - This shows the initial system cost, followed by a breakdown of your annual savings as follows:

FIT income - This is the annual income from the Feed In Tariff, set at 41.3p for every kWh you generate for <4kW retro fit installations.

Export Income – This is the annual income from electricity that you do not use, but export, currently 3p/kWh.

Import Savings – This is your annual savings figure from not having to import electricity that you are generating and hence using on-site.

Total Savings – This is the sum of the above three figures.

ROI – Return on Investment. This is the annual return as a percentage of the initial capital outlay.

25 Year Returns Button – This takes the annual Total Savings figure and applies it over the 25 year FIT duration. This shows when payback is achieved and the total income.

The above results are based on the Government's finalised figures for the Feed In Tariff, announced by Ed Miliband on the 1st February 2010. The calculator is based on the tariff for a sub 4kW system fitted on an existing property.