Given that the efficiency of heating your room is roughly 35%, what mass of natural gas is actually necessary to heat your room from 12.7 to 25 degrees.

Mass of natural gas needed to heat the room is 350,000BTUs

Explanation:

The heating efficiency of a furnace is never 100% because not all energy is released and not all heat is available to heat the place. A lesser efficiency requires more consumption of fuel. Heating values are used for heating fuels in order to calculate the mass of fuel needed.

The heating value of natural gas is 1,000,000BTUs

Therefore the formular for calculating mass of natural gas needed= Heating value of natural gas×efficiency.

Mass=1,000,000×0.35

Mass=350,000BTUs