Hi. A friend has recently purchased an apt with a hevac immersion tank. Anyway it's not installed properly and she has had a quote of 1600 to replumb it and set up a zoned system. I think this means she can set a room temperature in each room using valves in radiators. Also the gas boiler will heat the water without having to use the electric immersion. Apparently there is a grant of 650 that she can get. The total cost is 1600 before applying for grant. Does this sound excessive. It's a 2 bed apartment. Is there a good cost saving to be had by using gas to heat water ? Is it worth initial outlay ? Will it improve Ber rating ? Many thanks