How much energy I’m throwing out the window?


Sorry for the provocative question, but the most of the energy goes outside thru the window, the most of the heat that we produce for heating or the most of the energy used for cooling our home and our offices during the warm months.

Who made the first step towards improving energy efficiency with windows that provide a good insulation and a good seal to air flow, keeps intact the problem raised in the title of this post, having to open the windows periodically to ensure the necessary air exchange for oxygen, and to expel excess moisture especially in bathrooms and kitchen. But let’s not forget the importance to expel the chemical contaminants and the Radon (a radioactive gas) that accumulate in the environment in which we live.

But “how much energy I’m throwing out the window?” A lot, from 40 to 50% of the total energy produced, because is the energy contained in the dry air and in the humidity.

Actually we are able to ventilate the rooms with an ERV (Energy Recovery Ventilation) recovering the total energy (enthalpy =  sensible energy + latent energy contained in humidity) with an efficiency ranging from 80 to 90%, then we can point to no longer throw out the window 30 to 45% of energy consumed.

In winter we can also recover the large amount of energy contained in moisture (latent energy) that is generated in excess during a shower or while we cook, and no longer open the window during a long time.

Calculations on the amount of energy recovered “recycling” the air can be performed simply with simulators, some of which are free applications (will be discussed shortly in a future post).

Bye for now and thank you for joining us on .


About olivier

"ever green" electrical engigneer -