A typical 3.5kW grid-connected PV roof (covering about 25 square metres) is likely to cost around £6,000. Take a look at our Solar Calculator to estimate the cost for smaller or larger systems, and to see how long it will take to recoup this cost.
Maintenance costs are generally low as there are no moving parts, and the panels are expected to operate 30 years or longer (see How long do photovoltaic panels last?). The only major part that will probably require replacement twice over a system life span is the inverter, which costs £1,000 - £2,000 in a domestic system.
A domestic PV system will be particularly financially attractive if you’re undertaking substantial renovation work or building a house from new, as the panels can be used in place of roof tiles, and many associated costs (such as scaffolding) will be incurred when roofing anyway.