Solar Works.

Just be very carefule with who you get to actually install it. There's a lot of cowboys out and about there who will cut corners wherever possible in order to save a few quid. Then there's companies like Activ8 or TheEnergyCentre who have a particularly nasty sales strategey of staying in your home for hours at a time until you sign a contract and pay a deposit just to get them to fuck off.

Ideally, you can expect a ten year payback period, or thereabout, but the real value comes when you come to sell your home because adding renewable energies can really help your BER rating, especially if your house was built before 2005 or so.

The SEAI grant can be mixed bag because it can often require you to install more expensive technologies than you actually require to meet your needs.

Normally, it'll take two days or so to actually make the install. One day to fic the panels to the roof, and one more day to install the replacement cylinder.

Things you have to be aware of is not the overall on-paper performance of the system as a whole, but it's reliability. Your putting something on your roof that penetrates the roof envelope so you want to make sure that the company installing your panels take care to ensure the system remains weathertight.

You also have to consider the cylinder, which you really, really don't want to leak.

As for servicing, one of the biggest servicing costs is the replacement of Glycol antifreeze every 3-5 years or so, becuause that tends to degrade with age. You can sort of avoid this cost if you install a drainback system which can be filled with straight water since it's unpressurised and leaves the solar panels dry when it's idle.

I've a few friends who've installed drainback solar systems, and they're fairly happy with them