My boiler is nearly 20 years and only 65% efficient so I think its about time it was replaced!
I have received three quotations and all have suggested a larger boiler -18kW; the current boiler is 14.7kW.
I have done a quick calculation, based on the sizes of the radiators and output figures for similar sized radiators from the Stelrad catalogue, and have arrived at 15kW including dhw. This also agrees with the "whole house" calculation on the Sedbuk website. This suggest that the current boiler is the right size.
However, to complicate things. I am having the outside walls cavity insulated (detached house). According to the Sedbuk calculation this mean that I will only need an 11kW boiler.
My question is what size boiler should I install?
18kW (installers suggestion)
15kW (to match radiators)
11kW (sedbuk calculation)
By the way, its a heating only boiler - I don't want a combi.
Thanks
I have received three quotations and all have suggested a larger boiler -18kW; the current boiler is 14.7kW.
I have done a quick calculation, based on the sizes of the radiators and output figures for similar sized radiators from the Stelrad catalogue, and have arrived at 15kW including dhw. This also agrees with the "whole house" calculation on the Sedbuk website. This suggest that the current boiler is the right size.
However, to complicate things. I am having the outside walls cavity insulated (detached house). According to the Sedbuk calculation this mean that I will only need an 11kW boiler.
My question is what size boiler should I install?
18kW (installers suggestion)
15kW (to match radiators)
11kW (sedbuk calculation)
By the way, its a heating only boiler - I don't want a combi.
Thanks