The main energy reduction potentials recognised in the Houtvenne project were transmission losses, ventilation losses and hot water.

Transmission losses or gains represented a prime subject of attention. Through comprehensive insulation of the entire building envelope with insulating materials such as mineral wool and special double glazing, combined with energy economic design (compact building and passive solar energy design), the project managed to lessen the heating significantly.

The table below gives an overview of the insulation level of the different building parts.
 

The required energy for heating should be reduced from 220 kWh/mē/year to 50 kWh/mē/year. To achieve this, we applied principles of compact building, proper orientation, and extensive insulation (insulation level K24), condensing boilers, and mechanical ventilation with heat recovery.