Dew point is the temperature at which air becomes saturated and moisture condenses, affecting condensation control in construction and HVAC design.

Dew point is the temperature at which air can no longer hold all of its moisture, causing water vapor to condense into liquid. In construction and building science, dew point is a critical factor in understanding condensation, humidity control, and moisture-related performance issues.

In building envelopes and HVAC systems, dew point helps determine where condensation may occur within walls, roofs, ductwork, or mechanical systems. If warm, moist air contacts a surface below the dew point temperature, condensation can form—potentially leading to mold growth, corrosion, insulation damage, or material deterioration.

From a design and quality-control perspective, managing dew point is essential for occupant comfort and long-term durability. Engineers and designers use dew point calculations to size HVAC equipment, design vapor barriers, and prevent moisture accumulation in both residential and commercial buildings, particularly in humid or cold climates.

Air with a high dew point feels “sticky” or uncomfortable—even if the temperature isn’t very high—because moisture can’t easily evaporate from your skin.

• Point Load
• Yield Point