A1: South facing is ideal but an east facing roof will still deliver 75% of the energy of a south facing roof.
A3: No. Monocrystalline solar panels have a higher power output than polycrystalline panels but are more expensive. Hybrid (HIT) solar cells are as good as mono crystalline ones. Thin film are least efficient but cheaper. If you have a small roof space the more expensive more efficient panels will be worthwhile.
A4: Which? did a survey in May 2019 asking customers to score the different brands. There wasn’t much difference between the 15 brands with Hyundai, Canadian Solar and Sanyo at the top but Romag was clearly at the bottom.
A5: Commonly, 25-30 years for the panels and 5-10 years for the inverter. Insurance can be purchased for extending the warranty of the inverter.
A6: Which? asked solar panel customers in April 2019 about the problems they had experienced. About 10% had problems with the inverter and on average the problem occurred 4 years or so after installation. The next most common problem was nesting birds with 3% of customers reporting this.
A7: In a place like Ilkley, with very little air pollution, a heavy shower should be enough to clean them. If birds perch on your roof and soil the panels or you see a heavy build up of dust, maybe yes, you will need to clean them.