I have been thinking about getting pv panels on my roof. Our energy bills are eye-watering - a big house with a 98-year-old occupant takes a lot of heating in the winter. I thought that anything we can do to reduce our bills would be a good idea.
I had an estimate from Solar Century, who work with Ikea. I think they are reputable, but I asked a local man to give me another estimate for comparison purposes. I'm still waiting for him, but the SC estimate was for a bank of panels to be fitted to the eastern side of our roof. The ridge runs NNW-SSE, so those panels would be pointing a few degrees N of E - not ideal. The roof has quite a shallow pitch, so that wouldn't be a problem in the summer. The other side has a chimney which would cast a shadow over the panels for much of the afternoon so I assume that is why they have ruled that out.
In a nutshell, I don't think the returns justify the expense. Their estimate if for about £5800 with an estimated annual return (based on a who load of variables like government capping which they are in no position to predict) of 3.86%. That means that I would be in my late 80s before it had paid for itself, if I or it haven't conked out first.
I think if such a scheme were viable we would be amongst the households who would likely to benefit most: we run two electric cars and cover about 19000 miles a year. That's approximately 50 miles per day, or about £1.25 in electricity costs (in reality, less, as we don't do all our charging at home). I can't see us maintaining that sort of mileage for much longer - a good chunk is dedicated to looking after grandchildren and in a couple of years I expect that to reduce dramatically.
So we have decided not to go ahead with the installation. We already buy our gas and leccy from Ecotricity, who claim that everything they supply is 100% renewable. That means that a bank of solar panels on our roof would do nothing to aid the environment and little to reduce our bills. I wonder then - if we can't justify solar panels, who can?