Solar Heated Pool Running Costs

[ecs]

Seems like there's a few pool threads on here, didn't want to hijack any of them though!

I'm looking at buying a house with a smallish swimming (approx. 4x8m) - the property already has solar heating for hot water and the owners mentioned that they could have the pool heating system converted to use solar heating too.

Does anyone have any experience with the running costs for such systems? I believe the current heating system for the pool uses as gas boiler (I'm awaiting the full details) and I'd assume we'd still need to use this to heat the pool at the beginning of the season.

Also, could anyone suggest any other costs which I might not've considered? I know about winterisation/de-winterisation and a company comes out to do maintenance.