I am trying to calculate the potential savings of replacing my 12-year old D boiler (which still works perfectly) for a more efficient A-rated one. Based on the most recent annual consumption I arrive on a modest annual saving of only £68, or £1015 over 15 years. The calculation method which seems to be widely used assumes the unit gas rate to stay fixed, which is nonsense of course. It would be better if the calculation would use a variable to reflect any future rate changes.. Does anyone know how of a better method /know of a way to get historical figures that would help establishing trend /know of an organisation that does gas rate projections? Most grateful for any suggestions.
Best answer by woz
There are all sorts of things to consider when changing your boiler, but you can only compare on a like-for-like basis. which means ignoring all the other losses in the system and other optimisations that may be worthwhile as an alternative.
On the face of it the new boiler is only 9.5% more efficient than the existing one and you say it (the existing) is working perfectly.
How much would the total cost of the work be?
It's fairly clear from your figures that the "payback" time for your level of consumption is way too long to make it a worthwhile exercise.
Also the figures quoted are for the boiler only and don't take into account other losses. (which would be the same ££ but a greater percentage with a more efficient boiler)
From the figures given on the face of it I'd say it doesn't seem worthwhile. I can't see how conventional electric heating would cost you less (unless you have solar panels). The efficiency is much better (near 100% and no other losses) but the per kWh cost is at least 4 times as much as it is for gas.
Assuming your insulation is up to scratch - it has to be really good, have you looked at the idea of a ground source heat pump? There are government grants