testo 605i – Thermohygrometer Operated via Smartphone
Take charge of indoor climate assessment with a compact thermohygrometer designed for efficiency, accuracy and mobility. The testo 605i combines intelligent sensor technology with smartphone connectivity, giving you clear insights into temperature and moisture conditions wherever your work takes you.
Built for professionals who need fast, dependable results, this instrument supports informed decision-making across maintenance, HVAC and building performance tasks.
Smart measurement with mobile flexibility
Using Bluetooth® connectivity, measurement values are transmitted wirelessly to your smartphone or tablet, allowing you to work comfortably across large sites or multiple locations. With a range of up to 100 metres, the testo 605i keeps data flowing even when measuring points are widely spaced.
When paired with the testo smart probes app, readings are displayed clearly and intuitively. The app automatically calculates dew point and wet bulb temperature, helping you assess environmental conditions quickly without additional tools or manual calculations.
Practical design for real-world applications
Engineered for convenience, the slim housing and bendable probe head allow precise measurements in rooms and ducts, including areas that are awkward or difficult to access. This makes the instrument particularly useful for ventilation checks and air conditioning system assessments, including humidifier performance.
The device also integrates seamlessly with other Testo Smart Probes, enabling expanded analysis such as identifying mould-risk areas through guided measurement menus within the app.
Reliable results you can trust
With accurate sensing of temperature and air humidity, this instrument delivers dependable readings across a wide operating range. Its robust design supports consistent performance in both residential and commercial environments, ensuring confidence in every measurement.
Collected data can be visualised as tables or trend graphs and exported instantly as professional PDF or Excel reports, simplifying documentation and client communication.
testo 605i Key Features:
- Accurate measurement of temperature and relative humidity
- Automatic dew point and wet bulb calculation
- Long-range Bluetooth® connectivity up to 100 m
- Flexible probe head for challenging access points
- Clear visualisation and instant report sharing
- Compact design with professional measuring performance
▶ See the power of wireless performance:
What comes with the testo 605i:
- testo 605i Thermohygrometer
- Batteries included
- Calibration certificate
| Features | |
| Humidity – Capacitive Sensor |
| Measuring range | 0 to 100 %RH |
| Accuracy (at +25 °C) | ±3.0 %RH (10 to 35 %RH)
±2.0 %RH (35 to 65 %RH)
±3.0 %RH (65 to 90 %RH)
±5 %RH (< 10 %RH or > 90 %RH) |
| Resolution | 0.1 %RH |
| Temperature Sensor – NTC |
| Measuring range | -20 to +60 °C |
| Accuracy | ±0.8 °C (-20 to 0 °C)
±0.5 °C (0 to +60 °C) |
| Resolution | 0.1 °C |
| General Technical Data |
| Compatibility | iOS 8.3 or newer / Android 4.3 or newer
Requires mobile device with Bluetooth 4.0 |
| Storage temperature | -20 to +60 °C |
| Operating temperature | -20 to +50 °C |
| Battery type | 3 x AAA micro batteries |
| Battery life | 150 hours |
| Dimensions | 218 x 30 x 25 mm |
| Probe shaft length | 73 mm |
| Bluetooth range | Up to 100 m |
❓ Frequently Asked Questions (FAQ)
Q1: What does this instrument measure?
A. It measures air temperature and relative humidity, with automatic calculation of additional parameters via the app.
Q2: Do I need a mobile device to use it?
A. Yes, operation and display are handled through a compatible smartphone or tablet.
Q3: Is it suitable for ventilation systems?
A. Yes, the probe design allows accurate measurements in ventilation ducts and confined spaces.
Q4: Can I share results with clients or colleagues?
A. Yes, reports can be created instantly and sent by email as PDF or Excel files.
Q5: Which mobile systems are supported?
A. Compatible with iOS and Android devices that support Bluetooth® 4.0 or higher.