| I just had my central heating boiler serviced | by the gas company here, | for the first time in 14 years. | | The service engineer said the boiler (Potterton "Profile Prima") | as in good nick, which surprised me. | But he mentioned that there are now "condensing boilers" | which save a bit of heat, as they extract heat from the fumes | which are expelled outside the house in older models. | | Is it worth going over to such a model?
It is well worth doing the sums to see how much you would save. On our *very* well insulated extended semi, we spent only GBP 370 in 2004 on heating plus Domestic Hot Water, of which about GBP 150.
So if efficiency of a 25 year old boiler was about 70%, a high efficiency one 80% (sedbuk) and a condensing boiler 90% (sedbuk) we could only save GBP 37 per year going to a High Efficiency one and GBP 75 for a condensing one. These give payback times of 5 to 20 years depending on how much one allows for installation costs. In pure economic terms I would expect a payback of more than 10 years, and preferably over 20 years, the expected life of a boiler.
In our case, the change would not be cost effective. However, because the boiler was clapped out and as part of a remodeling of the kitchen it will go ahead, probably a condensing one, because it would be greener.
I would strongly suggest that you do some cost and savings estimates with your own figures, allowing a reasonable inflation factor for gas costs, before replacing a boiler which is in "good nick".