i have avoided the multiple threads on boards about solar because to be honest its becoming like religion there is just to many arguements for and against.
From the bit of research about efficiencys i have done, from selling them and from following there progress i have come to the conclusion it is not work investing in solar unless
1. You pressurise your entire house in which case you will also need a pressurised cylinder.
2. You introduce them at the stage of building
Either way i have come to the conclusion that the cost v's payback is not worth it.
Have to diss-agree on this one I'm afraid. I agree on Heinbloed's point.