Your heating system is 60% efficient. If it consumes 12,052 kWh of energy to heat
your house, how much useful energy(kWh) does it produce?

E = 7231.2 [kWh]

Explanation:

All systems that produce work in the mechanical form of movement or heat, they have an efficiency that depends on the construction technology, ideally in each of these equipments is that their efficiencies are as high as possible, that is, its efficiency is close to 100%. For this case we have an equipment with 60% efficiency, this heating system is characterized since of the 12,052 kWh, it uses 60% of this value only to heat the house, the rest of energy is known as lost.

E = 12,052 * (60/100)

E = 7231.2 [kWh]

This amount of energy 7231.2 [kWh] is used for heating purposes.