How do you measure a gas boilers efficiency

Mstty

Hopefully a simple question how can you tell the efficiency of a boiler one that's been installed for 15 years?

Rodders53

You can go by the spec of the boiler when new from the handbooks, and expect it to be perhaps a little worse with wear and tear.

To measure it will need lots of super expensive tech kit and likely the removal of the boiler to a suitable laboratory to do the measurements.

Mstty

Sort of confirms searches so far.

15 years just a little worse? 

I do wonder how you can prove the efficiency in real life not on a test bench even when they are new let alone up for replacement or repair.

BUFF

Flue gas analyser I believe. Often a printout given as part of a service.

Mstty

BUFF said:

Flue gas analyser I believe. Often a printout given as part of a service.

Yeah reading conflicting info they are mainly emissions detecting and not for efficiency.

BUFF

the results shoud be able to inform on combustion efficiency.
Obviously from that you can't tell how efficient e.g. the heat exchanger is so there will be some losses.

markin

Measuring the gas use and the temp rise of a stone cold water tank should be very close.