Calculation for HEAT INPUT

[steve799]

Hello.

If i know the HEAT OUPUT of a gas fire for example how would i use this to calculate the heat INPUT of this appliance if the data badge is not available. what is the correct formula for example if my heat output on a fire is 7.5kw ?
thanks

 

[Puddle]

Depends on design and operation of fire
you would have to contact manufacturer or see if you can find details on their web site

 

[kirkgas]

it is impossible to calculate as it depends on how efficient the fire is, you can do a gas rate calculation which will work out how much gas it is burning, but without the HI from the manufacturer to compare against it isnt very helpful.

 

[newbie1]

no way to know but if you gas rate it this will tell you heat input
if output is 7.5kw then fire is likely to be in the 6.7kw range..do the calculation and if its above 7.5 or way low at below 6 then suspect a problem