---
title: "Dew Point Sensors & Monitoring | Aethair"
description: "Dew point is the temperature at which air becomes saturated and its water vapor starts to condense. See how it is measured and which monitors track it."
url: https://aethair.io/parameters/dew_point/
---

Measurements · Meteorology

# Dew Point

Also known as dewpoint temperature, sample dewpoint

Dew-point temperature; the temperature at which air becomes saturated.

[Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure Dew Point Monitoring](https://aethair.io/build/?params=dew_point)

At a glance

°C Meteorology

3 ways to measure it

- **Aethair PRO** Built-in sensor
- **Aethair IAQ** Built-in sensor
- **Thiamis** 5 external instruments

What it is

## What is dew point?

Dew point is the temperature to which air must be cooled, at constant pressure, for the water vapor in it to begin condensing into liquid; in other words, the temperature at which the air becomes saturated. Unlike relative humidity, which changes with temperature, dew point is an absolute measure of how much moisture the air actually contains: a dew point of 15 °C means the same water-vapor content whether the surrounding air is warm or cool. It is derived from temperature and relative humidity, or measured directly with a chilled-mirror hygrometer. Dew point, temperature, and RH are three views of the same moisture state.

### Health and operational effects

Dew point is the most reliable single guide to muggy discomfort. Because it is independent of temperature, a high dew point (roughly above 16–18 °C) feels oppressive whatever the thermometer says, since the humid air limits sweat evaporation. That makes it a better outdoor comfort indicator than relative humidity alone, and it is an input to the heat index.

Operationally, dew point is the parameter that governs condensation. Whenever a surface (a window, a wall, a chilled pipe, a freshly machined part) falls to or below the air's dew point, moisture condenses on it, bringing mold, corrosion, electrical faults, and product spoilage. Compressed-air systems, refrigeration, drying processes, and building envelopes are all managed against dew point.

How it is measured

## How Dew Point Is Measured

In most monitors dew point is **calculated** from a co-located temperature and relative-humidity measurement using a standard psychrometric relationship, so its accuracy inherits that of the capacitive RH sensor and the temperature element feeding it. For demanding applications the reference method is the **chilled-mirror hygrometer**, which actively cools a small mirror until condensation forms and optically detects the onset, reading dew point directly and very accurately. Chilled-mirror instruments are used in laboratories and industrial process control; calculated dew point is standard in building, meteorological, and indoor-air-quality monitoring.

Built into Aethair PRO and Aethair IAQ 2

Measured by the monitor's own sensors, calibrated before it ships: nothing to add.

An instrument on Thiamis 5

A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account.

### Placing dew point monitoring

Because dew point is derived from temperature and humidity, the sensor is sited by the same rules: in the occupied or monitored zone, away from direct moisture sources, supply air, and heat sources that would bias the underlying readings. For condensation-risk assessment the informative comparison is between the air's dew point and the temperature of the coldest nearby surface, so pairing an air dew-point reading with surface-temperature information around cold spots, glazing, and thermal bridges is far more useful than a single room value.

### Every device and option that measures Dew Point 7

| Device / option | Type | Base platform | Measures |
| - | - | - | - |
| **Aethair PRO built-in sensors** | Built-in sensors | Aethair PRO | Dew Point [Heat Index](https://aethair.io/parameters/heat_index/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Illuminance / Light](https://aethair.io/parameters/light/) [Particle Count (by size)](https://aethair.io/parameters/particle_count/) [PM1](https://aethair.io/parameters/pm1/) [PM10](https://aethair.io/parameters/pm10/) |
| **Aethair IAQ built-in sensors** | Built-in sensors | Aethair IAQ | Dew Point [Formaldehyde (CH₂O)](https://aethair.io/parameters/ch2o/) [Carbon Dioxide (CO₂)](https://aethair.io/parameters/co2/) [Heat Index](https://aethair.io/parameters/heat_index/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Particle Count (by size)](https://aethair.io/parameters/particle_count/) [PM1](https://aethair.io/parameters/pm1/) |
| [Airmar](https://aethair.io/sensors/airmar-weather-stations/) · 110WX, 110WXS, 120WX… | Weather Stations | Thiamis | Dew Point [Absolute Humidity](https://aethair.io/parameters/absolute_humidity/) [Heat Index](https://aethair.io/parameters/heat_index/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Precipitation Intensity](https://aethair.io/parameters/precip_intensity/) [Precipitation](https://aethair.io/parameters/precipitation/) [Barometric Pressure](https://aethair.io/parameters/pressure/) |
| [Davis](https://aethair.io/sensors/davis-weather-stations/) · Davis Wizard III, Davis Wizard II, Davis Monitor… | Weather Stations | Thiamis | Dew Point [Heat Index](https://aethair.io/parameters/heat_index/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Leaf Temperature](https://aethair.io/parameters/leaf_temperature/) [Leaf Wetness](https://aethair.io/parameters/leaf_wetness/) [Precipitation Intensity](https://aethair.io/parameters/precip_intensity/) [Precipitation](https://aethair.io/parameters/precipitation/) |
| [Lufft](https://aethair.io/sensors/lufft-weather-stations/) · WS100, WS200, WS300… | Weather Stations | Thiamis | Dew Point [Relative Humidity](https://aethair.io/parameters/humidity/) [Precipitation Intensity](https://aethair.io/parameters/precip_intensity/) [Precipitation](https://aethair.io/parameters/precipitation/) [Barometric Pressure](https://aethair.io/parameters/pressure/) [Solar / Global Radiation](https://aethair.io/parameters/solar_radiation/) [Air Temperature](https://aethair.io/parameters/temperature/) |
| [Gill Instruments](https://aethair.io/sensors/gill-instruments-weather-stations/) · MaxiMet-GMX100, MaxiMet-GMX200, MaxiMet-GMX240… | Weather Stations | Thiamis | Dew Point [Relative Humidity](https://aethair.io/parameters/humidity/) [Barometric Pressure](https://aethair.io/parameters/pressure/) [Solar / Global Radiation](https://aethair.io/parameters/solar_radiation/) [Air Temperature](https://aethair.io/parameters/temperature/) [Wind Direction](https://aethair.io/parameters/wind_direction/) [Wind Speed](https://aethair.io/parameters/wind_speed/) |
| [AethLabs](https://aethair.io/sensors/aethlabs-specialty-air-analyzers/) · MA200, MA300, MA350… | Specialty Air Analyzers | Thiamis | Dew Point [Black Carbon](https://aethair.io/parameters/black_carbon/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Sample Flow](https://aethair.io/parameters/sample_flow/) [Air Temperature](https://aethair.io/parameters/temperature/) |

[Configure Dew Point Monitoring](https://aethair.io/build/?params=dew_point)

Where it is monitored

## Solutions That Monitor Dew Point

Each one links to the solution page showing what that industry measures it for.

### [HVAC & Building Management](https://aethair.io/solutions/hvac-building/)

Often added Monitor ventilation and filtration, with data for your BMS

### [Weather Stations & Meteorology](https://aethair.io/solutions/weather/)

Often added Professional multi-parameter weather monitoring

Article Library

## Reading on Dew Point

### [Aethair IAQ vs Kaiterra Sensedge Mini: IAQ Monitors Compared](https://aethair.io/resources/aethair-iaq-vs-kaiterra-sensedge-mini/)

Aethair IAQ vs Kaiterra Sensedge Mini compared on connectivity, sensors, accuracy, and platform, and how to choose the right commercial IAQ monitor.

### [How to Choose an Air Quality Monitor: PRO, IAQ, or Thiamis](https://aethair.io/resources/choosing-aethair-monitoring-device/)

Compare Aethair PRO, IAQ, and Thiamis to match the right device to your site, from commercial interiors to industrial and fenceline monitoring.

[All articles](https://aethair.io/resources/)

Related

## More in Meteorology

[Barometric Pressure](https://aethair.io/parameters/pressure/) [Air Temperature](https://aethair.io/parameters/temperature/) [Relative Humidity](https://aethair.io/parameters/humidity/) [Wind Speed](https://aethair.io/parameters/wind_speed/) [Wind Direction](https://aethair.io/parameters/wind_direction/) [Wind Chill](https://aethair.io/parameters/wind_chill/) [Precipitation](https://aethair.io/parameters/precipitation/) [Precipitation Intensity](https://aethair.io/parameters/precip_intensity/) [Heat Index](https://aethair.io/parameters/heat_index/) [Wet Bulb Temperature](https://aethair.io/parameters/wet_bulb/) [Absolute Humidity](https://aethair.io/parameters/absolute_humidity/) [WBGT (Heat Stress)](https://aethair.io/parameters/wbgt/)

Questions

## Dew Point FAQ

What is the difference between dew point and relative humidity?

Relative humidity is a percentage of the air's current capacity and therefore changes as the air warms or cools, while dew point is an absolute temperature that reflects the actual water-vapor content. Two rooms can share the same RH but very different dew points, which is why dew point is preferred when comparing moisture across different temperatures.

What dew point feels humid?

As a rough guide, dew points below the low teens feel comfortable, the high teens feel noticeably muggy, and values above about 20 °C feel oppressive, regardless of the air temperature. Because it is temperature-independent, dew point is a more consistent comfort cue outdoors than relative humidity.

Why does dew point predict condensation?

Condensation forms wherever a surface is at or below the dew point of the air touching it. So the dew point tells you the temperature at which windows, pipes, and walls will start to get wet. Keep every surface above it and no condensation occurs; that is the basis of managing mold and corrosion.

How do I monitor dew point?

The Aethair family (Aethair PRO and Aethair IAQ) derives dew point continuously from its built-in temperature and humidity sensors, so no separate instrument is needed for indoor condensation and comfort monitoring. Use the configurator to combine dew point with temperature, humidity, and, for surface-condensation studies, additional sensors connected through Thiamis.