I nearly forgot to report back with the first full year’s worth of performance from the array of solar evacuated tubes on the roof that feed our hotwater system.
Fortunately the basic datalogger I have access to still gives the basic ’08 readout, and it tells me the system ran for approx 1100 hours during the year and generated a staggering 3498 kWh.
Nottingham Energy Partnership’s comparison cost table suggests that might have cost me around £100-£150 if I’d had to pay for it in gas.
Although I didn’t watch the system too carefully throughout the year, I don’t think there was a single day on which all our hot water came from the sun.
It was an unusual year with a pretty lousy summer and the highest energy costs for gas and electricity we’ve ever seen, so there’s maybe chance for a better financial return in future. But at this rate, my payback period is 28-42 years.
It’s still one of the better gadgets I own, and second in cost only to my car. I like the readout that always tells me exactly how hot my hot water is – I know that for a good long hot shower I need the tank to be over 60deg, and I can check before going in if necessary.
Other posts about my solar panel: