Although the fuel (daylight) is free, the cost of the system can vary quite considerably. A typical household will consume around 3-4000kWh annually and so a typical system of between 1 and 5kW can meet between 25% and 100% of a households needs.

A typical price for a grid connected, building integrated PV system is between £6 and £7 per Wp, this works out at £12,000 - £14,000 for a 2 kWp system for a house. However, there are a number of factors that will influence the cost of a system:

• New build/retro fit - If the system is being installed on a new building some savings may be madethrough the direct replacement of building materials.
• Quantity – Through bulk purchasing agreements a house builder installing systems on a group of houses can expect to reduce the overall cost quoted per system than an individual householder requiring a single system.
• Size – as above a larger system may be cheaper per kWp while a small system may be more expensive.
• Access - The typical price assumes that the installation is on a typical house roof, if the roof is a complicated shape or requires complicated scaffolding costs will be higher.
• Module type – the type used will significantly impact on the costs. The typical price quoted is based on standard modules, tile type systems are somewhat more expensive. The most expensive systems use semi-transparent glass modules in facades or conservatory roofs

• Maintenance Costs

• Sell-back Agreements

Although it is possible to get a net metering deal where the amount paid for the electricity sold/exported is the same is paid for the electricity brought/imported it is likely that there will be difference with imported electricity being more expensive than that exported.