In 2007 I installed a solar hot water system from Navitron. The system saved us 500 litres of fuel oil per year and paid for itself in three to four years. About four years ago I changed the tank to a larger 500 litre one, designed for solar. (Effectively paid for by the annual savings). We immediately noticed our water was hotter. It has little or no maintenance to do, apart from checking the systems is at the correct pressure from time to time. Solar hot water was the best investment we could have had. And we are still ahead on savings.
In 2011 we had installed a solar pv system and we sell the excess electricity back to ERDF. The four kwh system generates a annual cheque for between €1340 to 1450. We took out a loan with our bank with a favourable interest rate for eco projects. The loan was for twelve years. The contract with ERDF to buy the electricity is for twenty years, with an excellent feed in tariff.
The panels will generate electricity for years beyond the contract. At the point the contract ends, if we were still here, I would have a battery storage system to save the electricity.
Our friends in the UK have a three kwh system which actually generates more electricity than our one 25% larger. Ours faces due south, but there are two problems. The first being the roof pitch at around 34° is not ideal. Ideally, the pitch of the panels should be that of your degree of latitude (approx 46°) to take advantage of the angle of the sun. Roof pitch in the UK is higher. The second problem is that French planning permission calls for the panels to be integrated into the roof. This doesn’t allow for good cooling and the hotter the panels are, the less they generate. With hindsight, we should have had both systems installed at ground level.
The inverter for the solar pv failed three weeks before the five year guarantee ran out. Fortunately, I got a new one free, apart from the installation cost.
Would I do it again? Not sure. The solar hot water, yes, without question. The outlay for the solar pv (You should really look at it as an investment in your future power costs. Our monthly direct debit to ERDF for the power is still less than we were paying before 2011, so we have gained there) was high. Our house is modern with good insulation as I had already increased it, but the double glazing is 26 years old, so could be more efficient. I think we will come out ahead, but these days with the lower feed in tariff, the payback time will be longer. Having said that, a lot of the installation companies (ours included) have gone bust. You have big name companies such as Ikea installing systems in the UK (not sure about here), so those that are around now, might still be here in years to come.
We have a surfeit of hot water in the Summer and I have often wondered if that surplus heat could be used to heat a pool. (We don’t have one). Navitron sell stainless steel heat exchangers for their systems, so some people must use it.
For us, solar power is definitely viable, but you have to weigh up your cost to change.
Just thought of this addition:- You will be told about tax rebates for such systems, but you need to look closely at it. We were told that we would get 50% off the cost of our solar hot water system, when we were looking at installers for that. That wasn’t true. It was 50% off the cost of just the panel. They were almost six times the cost here than elsewhere. Check upon what you might receive. That’s why I went for self installation (I did the course in the UK for £175 at the time. My total outlay including the costs of the system, travel, hotel bills and the course, as well as paying a plumber to connect to our boiler as I didn’t have the brazing equipment was less than £1500. Against quotes of €6000 and more to have the system fitted here.