I’ve been doing lots of consultancy work on solar PV installations, mainly for social housing landlords. I think the majority of FIT supported PV installations will be going on social housing roofs so therefore reducing the electricity bills of some of the poorer people in society.
Obviously it’s a good investment if you have got the cash and are not planning to move house.
It will also reduce bills by approximately 1/3 for most homes depending on electricity usage patterns.
Over a 25 year period you will need at least 1 inverter replacement. Most are warrantied for 10 years.
Most decent panels are guaranteed to not drop more than 10% after 10 years, and 20% after 25 years. So you might as well call that 1% reduction in generation per year.
They’re supposed to be self cleaning – there is no market for PV cleaners in Europe apparently (I’m not 100% convinced of this though).
Don’t pay more than £3,200 per kW installed for a roof mounted system.
Look for a contractor that’s been installing PV (and MCS registered ) for more than 5 minutes.
Oh and be careful about how you place them on your roof. Any shading, even minor, can cut the output significantly as the panels are wired in series.
Roof mounting shouldn’t be an issue with a reputable contractor.