Ask the Experts: Index Self Build: Expert Advice Q&A

Date Published:

26/06/2008

Underfloor Heating
I want to install underfloor heating on the ground floor of my home, but I am worried that my 10- year-old boiler won’t be up to it. Do I need to replace my heating system, including the boiler?
Graham Baird, Newcastle-upon-Tyne

If your boiler has been regularly serviced and was well specified in the first place it may well be able to cope with the change. At 10 years old, while not being as efficient as a brand new boiler, it should have quite a few years of life left in it yet.

Moving to underfloor heating will mean removing the ground floor radiators and circulation pipe work. Modifications will also be needed upstairs to make it run independently and to ensure that the controls function with the new arrangement. The ground floor installation should consist of one or several runs of plastic pipework snaking across each room. These are then taken back to a terminal manifold distribution system, which is installed next to the boiler.

I suspect you will then need a new pump to drive the hot water from the boiler around the circuit. The flow rate and temperature is normally different for underfloor circuits than for radiators, which may require additional controls on the manifold.

While underfloor heating removes the need for unsightly radiators, it requires insulation underneath it, and you should bear in mind that adding carpets and rugs will prevent rooms from heating effectively.

Peter Caplehorn, architect and technical director at Scott Brownrigg architects, planners and designers (01483 568 686; scottbrownrigg.com)