We are about to renovate and extend early 20th C Arts and Crafts cottage, and are considering heating options. What is the difference between combi and condensing boilers, and also, would UFH be suitable for the ground floor at least (the extension kitchen/dining/living room will have solid floors) and we will have two bathrooms.

I have been told that UFH is more expensive to run? True or False?

  • Tony Taylor


    A condensing boiler is one which has a very high efficiency and in basic terms uses the hot flue gases to pre-heat the incoming cold water to the boiler before it is heated to it’s delivery temperature in the heat exchanger.

    They can be more expensive, but would return the additional cost reasonably quickly by reducing the energy required.

    A combi or combination boiler is one which combines the heating of water for radiators and/or UFH with the delivery of hot water to the taps.

    There are multiple scenarios however, there are two basic configurations, a combination boiler with hot water delivery to taps and hot water circulated around the heating system radiators and a conventional boiler which circulates water around the heating system radiators and also around a coil inside a hot water cylinder (separate from the boiler), hot water is then drawn off the cylinder.

    Either system can (and ideally should) incorporate a condensing boiler to make the most of the higher efficiencies, also either system can be fitted with UFH to the whole or property or in particular areas.

    UFH provides an even output across the whole room and eliminates the need for radiators, which often results in a cleaner finish to the space, providing the correct controls are fitted, UFH should not cost more money to run than radiators.

    Trust this helps, please contact me if you need any further advice.


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