Are you up for the b&m challenge? When you talk to the heating engineer about your hot water needs, we think a good installer will mention some or all of the following for you to consider if they don't come up in conversation, ask about them. Are there any downfalls to combi boilers? Find out how to get a new boiler installed and how much it should cost we'll help make sure you don't get overcharged for your boiler installation. Sign.