Are SEDBUK ratings meaningful?

[Biggles..]

98.4%eff @ 100% load
109% eff @ 30% load!

As far as I know, nothing which burns gas alone can be more than 100% efficient. They use the calorific value of gas based on the heat produced by burning it only. The gross calorific value, or higher calorific value involves calculating the total heat released by burning the gas AND returning all combustion products (including the water vapour) to the same temperature as the gas before it was burned.
Therefore the figures are a load of carp anyway

All that bumf when its just a twist in the calculation that all manufacturers use to give figures.

The above Eco Tec is 45kw input and produces 46.4kw @30% load.
Its the use of nett/gross and the mix of the two that gives you the view that its over 100% eff.

 

[gaswizzard]

98.4%eff @ 100% load
109% eff @ 30% load!

So cutting through the BS the actual GCV being.............

98.4 ncv = 88.5%
109 ncv = 98%

Tis a play on figures and total BS.

 

[Biggles..]

They use net input and state gross output.