testo 175 H1 Dual-Channel Temperature and Humidity Data Logger

Overview

The testo 175 H1 is a dual-channel, high-reliability temperature and humidity data logger engineered for long-term environmental monitoring in regulated and non-regulated indoor settings. It operates on the principle of precision analog-to-digital conversion of signals from an external NTC temperature sensor and a capacitive relative humidity (RH) sensor—both calibrated traceably to national standards. The device continuously records time-stamped measurements of ambient temperature, relative humidity, and calculated dew point (Td), enabling rigorous assessment of thermal comfort, condensation risk, and hygrothermal stability. Designed for unattended operation over extended periods—up to three years on a single set of AAA batteries—the instrument features non-volatile memory with 1 million data points capacity, ensuring integrity during power loss or battery replacement. Its IP54-rated housing provides protection against dust ingress and water splashes, while the integrated anti-tamper lock secures both physical access and configuration integrity—a critical requirement for audit-ready environments.

Key Features

• Dual-channel measurement architecture: independent external NTC temperature probe and capacitive RH sensor for improved dynamic response and reduced thermal lag versus built-in sensors
• Calculated dew point output derived in real time using the Magnus formula per ISO 4677-2, referenced to measured T and RH values
• Automatic data backup upon battery depletion or replacement—no measurement gaps or data corruption
• High-contrast backlit LCD display showing live values, user-defined alarm thresholds, exceedance status, battery level, and elapsed logging time
• Configurable measurement interval from 10 seconds to 24 hours—optimized for both transient event capture and multi-year trend analysis
• Robust mechanical design: lightweight (130 g), compact footprint (149 × 53 × 27 mm), and wall-mountable with included bracket and security lock
• Long-term sensor stability: <1 %RH/year drift (at +25 °C), validated per IEC 60751 and EN 60068-2-30 for humidity sensor aging

Sample Compatibility & Compliance

The testo 175 H1 is validated for continuous monitoring of air in enclosed spaces—including office buildings, archives, pharmaceutical storage rooms, museums, cleanrooms (non-classified zones), and logistics hubs. Its external probe configuration ensures accurate representation of ambient conditions without enclosure-induced thermal inertia. The device complies with EU Electromagnetic Compatibility Directive 2014/30/EU and RoHS Directive 2011/65/EU. While not intrinsically certified for hazardous areas, its IP54 rating supports deployment in typical commercial HVAC environments. For GxP-regulated applications, optional ComSoft CFR 21 Part 11 software enables electronic signature support, audit trail generation, role-based access control, and data integrity assurance aligned with FDA expectations for electronic records.

Software & Data Management

Data retrieval and configuration are performed via testo’s ComSoft software suite. ComSoft Basic (freely downloadable) supports essential functions: instrument setup, real-time monitoring, raw data export to CSV or Excel, and basic graphical visualization. ComSoft Professional extends functionality with statistical analysis (min/max/mean/deviation), custom report templates, multi-device fleet management, and automated email alerts. ComSoft CFR 21 Part 11 adds full 21 CFR Part 11 compliance—including electronic signatures, immutable audit trails, user authentication, and system validation documentation—making it suitable for pharmaceutical cold chain validation, warehouse qualification (IQ/OQ), and GLP/GMP-aligned environmental monitoring programs. Data transfer occurs either via mini-USB cable (sold separately) or removable SD card (not included), supporting offline deployment in locations without direct PC connectivity.

Applications

• Continuous validation of HVAC performance and indoor climate stability in office and institutional buildings
• Environmental qualification of storage areas for archival materials, medical devices, and reference standards
• Monitoring of temperature-humidity excursions in pharmaceutical distribution centers and controlled-room-temperature (CRT) storage zones
• Supporting ISO 14644-1 cleanroom classification studies by documenting baseline hygrothermal conditions
• Energy efficiency audits—correlating occupancy patterns, HVAC runtime, and microclimate variability
• Compliance reporting for LEED IEQ credits, BREEAM Hea 02, or national building energy codes requiring documented environmental parameters

FAQ

What is the maximum recommended continuous operating time before recalibration?
The testo 175 H1 is designed for stable long-term use; however, annual verification against traceable reference standards is recommended per ISO/IEC 17025 guidelines—especially when deployed in quality-critical applications.
Can the device log data without being connected to a PC?
Yes. All measurements are stored autonomously in internal flash memory. No PC connection is required during logging—data retrieval occurs post-deployment via USB or SD card.
Is the external sensor replaceable or field-calibratable?
The NTC and capacitive RH sensors are integrated into a single external probe (order no. 0572 0175); replacement probes are available. Field calibration is not supported—the unit is designed for periodic lab-based adjustment using accredited calibration services.
Does the device meet requirements for EU GDP Annex 9 or USP <1079>?
When used with ComSoft CFR 21 Part 11 and configured with appropriate alarm limits, SOPs, and change control procedures, the system supports compliance with GDP Annex 9 (cold chain monitoring) and USP <1079> (environmental monitoring systems), subject to site-specific validation.
What happens if the SD card is removed mid-logging?
Removal of the SD card does not interrupt logging—the device continues recording to internal memory. The SD card serves only as an optional data offload path and is not used for active storage during operation.