The mission of designing high-performance buildings that promote sustainable objectives has led to new success stories but has also revealed vulnerabilities for potential mold and moisture failures.
The interaction between a building's HVAC system and envelope creates an unusually high-risk area. Any deficiency in either system can cause dramatic, building-wide moisture and mold problems. Through the emergence of high-performance buildings combined with the use of certain new green products, designers and contractors have inadvertently created high-risk buildings when, in fact, the goal should be to develop high-performance buildings with the lowest possible risk of failure.
There is no building envelope which a creative architect can envision that a poorly designed or performing HVAC system cannot destroy. Conversely, a well-performing HVAC system can often compensate for a marginally designed (or constructed) building envelope to the point that mold and moisture problems may never be noticed. However, even an exceptionally well-performing HVAC system cannot compensate for a poorly designed wall system.
A simplification of the above concept can be stated as follows:
- Bad Envelope Design + Bad HVAC Design = Guaranteed Moisture Problems
- Good Envelope Design + Bad HVAC Design = Likely Moisture Problems
- Bad Envelope Design + Good HVAC Design = Likely Moisture Problems
- Good Envelope Design + Good HVAC Design = Likely Success