Retrotec USACE - Manual (Page 133)

Appendix D D3
D1.1.2 Walls Have Multiple Penetrations in the Air Barrier (Waste)
Figure D3. Intended openings in the building envelope in newly constructed (left) and in retrofi t
(right) buildings.
20.0 °C
30.0 °C
20
22
24
26
28
30
MIN: 19.9 °C
24.6 °C
25.4 °C
Figure D4. Unintended air leakage in the building’s envelope: picture and a thermal image of
the wall in a swimming hall, showing air and thermal leakage area.
Multiple openings in the building walls (intended and unintended, see Figure
D3) and other elements can increase air leakage and consequently increase
heating and cooling costs. In humid climates, uncontrolled air leakage allows
humid air to enter buildings, creating humidity problems with a potential for
mold and mildew (Figure D4). In many cases, excessive air leakage can over-
power mechanical systems, making control of temperature, humidity, and out-
door pollutants impossible under many weather conditions. Appendix E con-
tains further information on air leakage pathways and their sealing.