Combi's tend to give plenty of heat if piped and pumped properly. It's the domestic hot water production that is limited. Any Baxi you would be looking at would have at least 1/2 the capacity of your TK1S.
these things are overhyped by deceptive advertising. they are just the latest thing in a long list if items used to seperate gullible people from their money. do your research before you waste your money.
