So far, i've had quotes from 9 solar energy firms for a system on a 17.5sq m roof, ranging from £8750 to £17500, which would provide somewhere between 1.75 and 2.9kws, depending on the panels and inverter. As one might expect, each firm has the best system available and each has different strengths which make it so. Every rep/contact has maintained that its panels are superior, giving reasons why mono- and poly- or multi-crystalline panels are better and also why hybrid (a combination of mono- and amorphous crystalline) are better. At present, it would appear that the latter are about 4% better in terms of converting solar energy to electricity but I'm guessing that further developments will follow soon. Ideal Home Group sent a rep who stayed for about 2 1/2 hours, told us loads of stuff, most of which we couldn't remember afterwards, and mentioned the "monitor home" idea which would give us a £1k discount, which we declined. Two days later, we got a phone call from the Sales Manager who almost immediately dropped the price to £12436, since when he has phoned at least 4 more times. Pv solaruk also offered the "monitor home" idea, dropping from £10750 to £8750 if we signed up immediately: we declined. However, they did mention a point no-one else had, and that was the kick-in point of the inverter, ie. the number of volts the panels have to produce in order to fire up the inverter and start producing electricity for use. They used the Power-one inverter which kicks in at 175v, whereas they claimed that others, eg the Sunnyboy, didn't kick-in until 250v, losing 2 or 3 hours of sunlight while they warmed up. I haven't yet found support for this. The hybrid panels made by Sanyo seem a good bet as they pick up light at low levels and angles, which seems good in UK but trying to pick the right system and installer is hard. The nationals give all the warranties and long-term reliabilty but seem to be locked into deals with particular suppliers, while the independents seem more able to supply a tailored system but may not have the long-term guarantees. No decision as yet.