The public has a proven track record of paying for things they THINK they need.
I've convinced mine to have their aready clean windows cleaned "to keep on top of them"
If you can charge £2-3 per panel for a domestic and half that for commercial multi system sites then go for it. However I would caution using % increase as a blanket selling point for 2-3kw systems as those that have installed them probably only just get their money back in 5 years.
My customers complain that the benefit to them is less than £100 per year on small systems so in effect, even though they get 'free' electricity, what they have done is pre pay for it.
% increase is not our only selling point. Have you visited our website? It's quite informative as to the other benefits of having your panels cleaned. Obviously the smaller the system, the smaller return. Residential is not our main market.
Your customers should have known they were pre-paying for their electricity before they bought the panels. It won't take 5 years to get their money back, nearer 11, but after that they will be in profit.
Also, arrays produce most when people are at work and we use most power after dark when the panels produce less so clients need to do everything in order to maximise their return. The more informed installers are now including maintenance as part of their sales pitch along with panel degradation. The industry is changing people's attitudes from 'have panels to make money', which was flawed, into 'have panels to save money'. Because the government changed the FiTs, you can still make money, but it is harder. You will however SAVE A LOT of money over the course of 20 years with energy price increases.
I don't own my own house, but if I did, I would fit panels. It is a no brainer. There is a huge stockpile of panels in warehouses at the moment and installers are offering the cheapest deals ever. The FiT is lower, but cost of installation is %wise lower still. ROI-wise, you get a better deal now than when the FiT was at its highest.
If you own a house and think you will stay in it, you should fit panels now.