Advanced Condensing boilers, the laymans guide

A condensing boiler is a efficient forward-looking boiler that integrates an extra heat exchanger in order that the hot flue gases transfer most of their contained energy to start to heat the cold water input. When running at a good efficiency, the water steam produced in the operating action condenses back into clear water liberating the latent heat of vaporisation.

A side effect will be this liquid, named condensate, most times acidic, needs to be piped outside to a drain or water drain. The boiler will be placed to a wall and the output fumes will travel through the flue. Hot water is supplied by a small-scale storage tank to ensure rapid hot water availability.

What size of Boiler do I need?

In earlier years boiler installers filled bigger boilers than were needed. Whilst this meant that there was no possibility of the boiler neglecting to meet the requirement for heat, without any care for icy weather, it also meant that they were primarily running at a reduced capacity, and so running under their configured optimal efficiency. If you have installed additional loft or cavity wall insulating material since the previous boiler was installed, it could well be that you will need a humbler boiler than the current one.

We urge looking for professional advice from a CORGI recorded fitter before selecting an appropriate replacement boiler.

Do the radiators need to be oversize with a condensing boiler?

The main efficiency benefit from a condensing boiler is that it has an oversize heat exchanger. Bigger radiators would result in cooler return water temperatures, and so enable greater energy efficiency, but the further economies suffer from decreasing returns, as you need to remember that that the system is working at very low capacity for the greater part of the wintertime. Whilst this assertion is correct householders would likely accept this in smaller properties.

These events were studied during the SEDBUK initiative, and had a look at the recommendations for condensing boilers. The result was that no new recommendations were expected, and the test results for both cases employ the same SEDBUK calculation.