My brother is in the process of renovating a house to live in. He has had most of the work completed, new electrics,pipework for central heating, plastering ,etc and his plumber has coming back next week to install a Worcester combi boiler. His plumber has told him that he must have a roomstat in the system. My brother does not want to start messing up the new plasterwork by channeling for cables and wanted to fit temperature valves to all rads only but his plumber said he must have a roomstat also.Is this right. Could you experts please give some advice .Many thanks.