Condensing boilers, your concise summary
A condensing boiler is a high efficiency innovative boiler that incorporates an extra heat exchanger so that the hot waste air transfer a percentage of their inherent heat to start to heat the cold water input. Once functioning at a good efficiency, the water steam developed in the burning process distills back into liquid form liberating the latent heat of vaporisation.
A consequence results in this water, called condensate, typically acidic, will need to be piped outside to a drain or water drain. The boiler will have to be mounted to a wall and the waste gases will travel through the flue. Hot water is initialy served by a little recepticle tank to enable speedy hot water availability.
What size of boiler should I get?
In earlier days boiler installers filled bigger boilers than were needed. Whilst this meant that there was never the chance of the boiler being unable to render sufficient hot water, even in the coldest wintertimes, it also meant that they were mainly working at a part load, and so functioning in an ineffective way. If you have fitted additional loft or cavity wall insulating material since the previous boiler was installed, it is highly likely that you will be recommended to install a smaller boiler than before.
We advocate looking for professional advice from a CORGI recorded fitter before selecting an appropriate replacement boiler.
Do the radiators need to be oversized with a condensing boiler?
The underlying reason for this improved efficiency from a condensing boiler is because it holds a bigger heat exchanger. Larger 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, as you need to remember that that the system is considerably under-loaded for the majority of the heating season. That in all probability remains true, though the smaller heating requirement for new build may well mean that householders would now allow over-sized radiators more willingly.
These consequences were counted during the SEDBUK project, and assessed whether there required to be new conditions for condensing boilers. The result was that no new recommendations were required, and the test results forall the boiler types use the same SEDBUK calculation.
