Hi. We've got them for water and energy The plus is, they provide lots of hot water and payments for what we feed in. In fact, for just two of us, they provide too much hot water and we have to drain it off. The minus. They were expensive and you'd have to know you'll be in this house long enough for them to pay for themselves. Also we've had a couple of calls out for bits not working and one expensive service, to set against the profits.. I wouldn't have them again if we move. I don't think we'll ever be living anywhere ever again for long enough for them to pay for themselves. If you're happy that they're helping the environment, that's another consideration. Also , if you decide to go ahead, bargain with the company. After we'd started going into it, different companies started contacting us with different prices and salesman we choose brought the price down when we wavered..