If warm air blows through cracks to the outside near the insulation, the best thermal insulation cannot work 100%. Warm air rises, and the warmer it is, the more intensive its lift. Then if cracks and openings are present, warm air escapes and cold air flows in from other place.

Heating a cubic meter of air from 0 to 20º C requires 6.6 watts. If this cubic meter is exchanged three times per hour through cracks and openings, then this is 19.8 watts per hour or an additional energy consumption of 475 watts in 24 hours. This corresponds approximately half a liter of fuel oil per cubic meter each day. This shows that building tightness bears a substantial saving potential.

Wind can be even more dangerous than natural convection. When it presses against the building, it presses warm air outward and losses can be substantial. Doors, gates and windows are the most frequent sources, but also transitions between wall and ceiling, ground and roof slope.

A tight building cover saves energy

Examine the building shell and take appropriate measures to save high energy costs without much expenditure. To find leaks in the building shell, the most suitable solution is a blower-door measurement in combination with infrared photography.