New Condensing boilers, the laymans guide

A condensing boiler is a high efficiency advanced boiler that incorporates an additional heat exchanger in order that the red-hot flue gases transfer a percentage of their contained energy to pre warm the water in the boiler system. Once working at high efficiency, the water gases developed in the burning action condenses back into a liquid putting out the latent heat of vaporisation.

A consequence is that this liquid, refered to as condensate, typically acidic, required to be piped outside to a waste pipe or water drain. The boiler is recommended to be mounted on a wall and the output gases will travel through the flue. Hot water is served by a small-scale storage tank to facilitate speedy hot water accessibility.

What size of boiler should I purchase?

In earlier years boiler installers filled larger boilers than were called for. Although this meant that there was little probability of the boiler falling short on its requirements, irregardless of the wintertime weather, it also meant that they were only using a piece of their heat generation capabilities, and so functioning in an inefficient way. If you have bettered the energy efficiency of your property since the previous boiler was installed, you will probably find that you will need a smaller boiler than the current one.

We recommend looking for professional advice from a CORGI registered installer before selecting a suitable replacement boiler.

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

The fundamental reason for this improved efficiency from a condensing boiler is that it has an oversized heat exchanger. More Prominent radiators would result in cooler return water temperatures, and so enable greater energy efficiency, but the further saving is not shown to be cost effective, keeping in mind that the system is is only using a small part of its total capacity for the greater part of the wintertime. That in all likelihood remains true, though the reduced heating demand for new build may easily mean that homeowners would now allow over-sized radiators more willingly.

The SEDBUK initiative assessed these subjects, and evaluated whether there needed to be new considerations for condensing boilers. The result was that no new recommendations were necessitated, and the test results forthe condensing and the existing boilers use the same SEDBUK calculation.