[danans]

> Regarding gas condensing boilers and their efficiency, the notion of them achieving over 100% efficiency, as measured by the Lower Heating Value (LHV) of the fuel, really showcases the value of recapturing latent heat.

At least in the US (not sure where you are), combustion boiler/furnace efficiency is required to be calculated using the HHV, which includes the heat of vaporization, not the LHV. The result is that even the highest efficiency condensing combustion heating systems all have rated efficiencies below 100%, which makes sense thermodynamically.

It seems that the standard in Europe is to instead calculate efficiency using LHV, resulting in the efficiency rating over 100% for condensing boiler. > 100% doesn't make sense thermodynamically, but is good enough for comparing when the same calculation is used.

Either way, it should be made more clear in the UI that it is using LHV.

[pandora-health]

To calculate the cost using a UK gas price we would want to have assumed an efficiency in HHV. This is because UK gas prices are given on an HHV basis. Either convention can be used as long as all of our fuel consumptions, efficiencies and energy prices are given on the same basis. Consistency is crucial.

[danans]

> This is because UK gas prices are given on an HHV basis. Either convention can be used as long as all of our fuel consumptions, efficiencies and energy prices are given on the same basis. Consistency is crucial.

If your audience is global, perhaps consider adding a toggle to switch the efficiency calculation to HHV. Think of it like the °C/°F toggle on some sites and apps.