ISO 13675:2013 is the general standard on generation by combustion sub-systems (boilers) for oil, gas, coal and biomass burning.

It specifies the

• required inputs,
• calculation method, and
• resulting outputs

for space heating generation by combustion sub-systems (boilers) including control.

ISO 13675:2013 is also intended for the case of generation for both domestic hot water production and space heating.