Understanding Dew Point: Why It Matters in Compressed Air Quality
If you’ve ever opened a drain on your air tank and watched water pour out, you’ve already seen what dew point really means. It’s the temperature at which moisture in the air turns into liquid — and in a compressed air system, keeping dew point under control is one of the most important parts of maintaining clean, reliable air.
At Industrial Air Services, we spend a lot of time helping facilities across Nashville, Knoxville, and Chattanoogasolve moisture problems. And nine times out of ten, it all comes back to dew point.
Here’s why dew point matters — and what you can do to keep it where it should be.
1. What Dew Point Actually Is
Dew point is the temperature where air becomes saturated with moisture and begins to form condensation.
When air is compressed, the moisture becomes concentrated. As the air cools, that moisture condenses into liquid water. The warmer or more humid the air is going in, the more water you’ll get coming out.
Understanding dew point helps you know:
How much moisture is in your air
How well your dryers are working
Whether your system is at risk of contamination
It’s one of the most important indicators of air quality.
2. Why Dew Point Matters in Compressed Air Systems
Moisture isn’t a minor inconvenience — it can cause real damage. High dew point air leads to:
Corrosion in pipes, valves, and tools
Shortened equipment life
Clogged filters and dryers
Poor lubrication in pneumatic tools
Product contamination
Water buildup in tanks and low spots
If your system has pressure drops, rust flakes in lines, or water spraying from tool connections, dew point is likely too high.
3. Tennessee Humidity Makes Dew Point a Bigger Problem
Our region is known for hot, humid summers — the exact conditions that overload dryers. When dew point rises outside, dew point rises inside your air system unless your equipment is sized correctly.
During summer, a poorly performing dryer can easily become overwhelmed. That’s why humidity control is essential for Tennessee facilities, especially those in food, automotive, medical, and manufacturing industries.
4. How Dew Point Is Measured
Facilities typically monitor dew point in one of three places:
At the dryer outlet (to check dryer performance)
In the main distribution line
At critical points of use
A dew point sensor tells you when moisture levels are creeping up so you can correct problems before they cause downtime or contamination.
5. Refrigerated vs. Desiccant Dryers
The type of dryer you use determines what dew point you can achieve.
Refrigerated Dryers
Dew point: 35°F–50°F
Great for general manufacturing
Affordable and low-maintenance
Struggle in extreme humidity or very cold environments
Desiccant Dryers
Dew point: -40°F or lower
Ideal for sensitive applications
Essential for food, medical, or instrument-grade air
More maintenance required
Many Tennessee plants use a refrigerated dryer as their main dryer and a desiccant unit for critical areas.
6. Dew Point Spikes Are a Warning Sign
If your dew point starts drifting upward, something is wrong. Common causes include:
Saturated desiccant
A failed refrigeration system
Undersized dryers
Clogged filters creating pressure drop
Faulty or clogged condensate drains
Excess moisture due to weather changes
Ignoring dew point spikes almost always leads to water in lines.
7. Good Piping Design Helps Control Dew Point Issues
Proper piping reduces the effects of moisture by:
Sloping lines for drainage
Taking drops from the top of the main line
Installing drains at low points
Using corrosion-resistant materials
Even with a perfect dryer, bad piping can undo everything by allowing cold spots where moisture condenses.
8. Point-of-Use Dryers and Filters Add a Final Layer of Protection
If you have processes that simply cannot tolerate moisture, adding small point-of-use dryers at the workstation ensures dew point stays low right where it matters most.
This is common in:
Food packaging
Medical molding
Painting and finishing
Instrument air systems
These units catch what the main dryer might miss.
9. Routine Maintenance Keeps Dew Point Under Control
Dew point problems often come down to maintenance. Keep an eye on:
Filter replacement schedules
Desiccant saturation
Refrigerated dryer performance
Drain operation
Cooler cleanliness
Dryer inlet temperature
Small issues here can snowball into big moisture problems later.
10. Dew Point Monitoring Protects Your System 24/7
Modern dew point monitors give real-time data — and can send alerts when moisture rises above safe levels. This helps prevent:
Product defects
Long-term corrosion
Unexpected shutdowns
Dryer failures
It’s one of the best investments you can make if air quality is mission-critical.
Dry Air Means Better Performance, Better Products, and Fewer Repairs
Understanding dew point isn’t just for engineers — it’s essential for anyone who depends on compressed air. The lower and more stable your dew point, the cleaner your air will be and the more reliable your operations become.
If you’re seeing water where it doesn’t belong, let us take a look. We’ll help pinpoint the issue and get your dew point back under control.
Industrial Air Services proudly serves Nashville, Knoxville, and Chattanooga, providing expert dryer service, dew point monitoring systems, compressed air audits, and full moisture-control solutions.
📍 138 Bain Drive • LaVergne, TN 37086
📞 (615) 641-3100
🌐 www.industrialairservice.com
