Dew point Calculator, Easy Calculate Dew Point

Dew point calculator

Calculate dew point with the dew point calculator to make your works simple.

In HVAC, air temperature is only half of the story. Have engpocket friends ever seen chilled water pipes or duct sweating so much till it damage the ceiling? This phenomenon is called condensation, and it happens because the material surface temperature dropped below the dew point.

Understanding the dew point is critical for HVAC engineers and contractors to determine the correct insulation thickness and maintain a healthy, mold-free environment.

What is dew point?

Dew point is the temperature at which air becomes very saturated with water vapor and that the vapor begins to condense into liquid water droplets (dew).

Why we calculate dew point?

1. To prevent condensation. Ensure that pipe and duct surfaces stay above the dew point, so they don’t drip water.
2. Indoor air quality (IAQ). A high dew point (above 62°F / 17°C) makes a room feel sticky and make the growth of mold and mildew.
3. Electronics safety. For examples in data centers or pharmaceutical industries, maintaining a dew point below the condensation threshold is vital to prevent short circuits in sensitive equipment.

Want to know how the dew point calculator works?

Check out the dew point formula

$$T_d\approx T-\frac{(100-RH)}{5}$$

• Td​ = Dew point (°C)
• T = air temperature (°C)
• RH = Relative humidity (%)

Case example

A pharmaceutical storage room has an air temperature of 28°C and a relative humidity (RH) of 65%. Estimate the dew point (Td) using the dew point formula:

What we know:

• Air Temperature (T) = 28°C
• Relative Humidity (RH) = 65%

$Td \approx T – \frac{(100 – RH)}{5}$

$Td \approx 28 – \frac{(100 – 65)}{5}$

$Td \approx 28 – \frac{35}{5}$

$Td \approx 28 – 7$

$Td \approx \mathbf{21^\circ C}$

So, the dew point is 21°C. To prevent moisture damage in the pharmaceutical packaging or mold growth on walls, all surfaces like shelves, pipes, or walls in this room must be kept above 21°C. If any surface temperature drops below this point, condensation will occur.

Dew point trend line graph

This trend line will be the compliment of the dew point calculator

That is all for the dew point. We have relative humidity calculator that engpocket friends can use in this link. Also wet bulb calculator on this link.