Condensing Boilers - Condensing Mode

Cardew

I have read up quite a few websites to try to get answers on getting condensing boilers to operate at their highest efficiency in domestic situations and and can't say I am much the wiser how you achieve this under all conditions.

There is much conjecture that the theoretical 90+% efficiencies claimed by manufacturers is just 'pie in the sky' and akin to manufacturer's MPG claims for cars.

Obviously you won't get manufacurers giving frank explanations of likely 'real world' efficiencies. I found this statement by the Royal Institution of Chartered Surveyors

The average cost of installing one of these modern boilers is £1,720, but saves on average just £95 off people's gas bills."

To illustrate the principle, take as an example a house with, say 5 bedrooms, 3 bathrooms and 4 reception rooms. Sometimes during the day you might only want to heat one or two rooms, at other times all of the rooms.

When all of the rooms are heated, there will be a lot of heat dissipated and it is easy enough to see that the return temperature of the water will be low enough to enable condensing.

However what about when just one or two rooms heated and little heat is being dissipated?

This is interesting!

http://www.condensingboiler.org.uk/ .

welda

When I changed from oil to gas, at this time I asked a colleague who trains/assesses gas engineers, to advise me on a good make of boiler, this was at the time when condensing boilers were being phased in. Colleague passed in to my house to assess my requirements, fair size, 14 rads, all with TRV's, except two en-suites, with non TRV valves (by-pass rads).

Rare to have all the rads on, most sit at "frost" setting, unless extremly cold. I was basically advised at this time to purchase a traditional boiler, as I would save very little with a condensing boiler, this was due to how I run my system.

I should add, and to give credence to colleague, he had attended a few seminars regarding intro of condensing boilers. I was lucky to purchase traditional, before totally phased out!!

Again, figures based on ideal lab conditions with regards to efficiency savings!