I enclose a copy of my KWH generation figures for the installation at my address. The installation which came on line in the last week of September 2011 has produced 449kwh in 24 weeks. Not sure if this is lower than expected from a 4kw system for the six months over winter in this part of the world. However I am beginning to notice a marked increase in daily generation figures as the days lengthen.
The system was completed by the installation team very efficiently and courteously and I am pleased with the aesthetic look of the system on my garage and house roof (since the installation is in two parts) to give me a 4kw system. The on the roof photovoltatic panels resisted some of the heaviest winds we have had in these parts for a good number of years which brought down a good number of mature trees, so I am confident that the installation will last.
Just a point that may help some of your customers. My invertor is located in a cloakroom on the ground floor and I was regularly looking at the readings on the inverter equipment. Scottish Gas offered a free device connected by Bluetooth which shows instantaneous and aggregate usage figures which should be connected to the mains input side of the meter. I have connected it to the output side of the photovoltaic system which shows me instantaneous and aggregate figure for generation and saves me rummaging about the coat cupboard. Although only about 95% accurate it is close enough to let me understand when we are producing a lot of electricity at a glance in the kitchen. Even more useful for customers who have the inverter fitted in say the loft space or garage.