U23-001-P HOBO Data Logger for Relative Humidity & Temperature with PVC Protector




Temperature and Relative Humidity Data Logger with special PVC protector for harsh environments.

Add to wishlist

Number of Channels 2: Temp + Rel. Humidity
ADC Bits 12 bit
Precision 0.2°C in range from 0° to 50°C
Resolution 0.02°C
With Display No
IP Classification IP67
Communications Optic
Battery Life 3 years
Memory Capacity 21,000 Temperature and RH measurements

The HOBO U23-001-P Thermo-hygrometer Temperature/Relative Humidity data logger U23-001-Protector is a data logger with an external PVC protection structure that serves as solar radiation shield, rain protector and allows it to be deployed outdoors hung to a tree or horizontal post.
It has a cap that allows access to the logger in order to read off data. 

The built-in temperature and relative humidity sensors are well protected from outdoor climate.
The more protected Relative Humidity sensor provides superior durability in humid environments and is user replaceable.



  • Removable PVC weatherproof housing for use in outdoor or condensing environments
  • High accuracy
  • Replaceable Relative Humidity sensor provides fast response and superior recovery from condensing conditions
  • Small-diameter external sensor versions for measurements in tight spaces
  • Optic USB interface for fast and reliable download of data in-the-field

Temperature Sensor:
Operation range:
Internal sensors: -40° to 70°C (-40° to 158°F)
Accuracy: 0.2°C over 0° to 50°C (0.36°F over 32° to 122°F)
Resolution: 0.02°C at 25°C (0.04°F at 77°F)
Response time: (typical to 90%)
Internal sensors: 40 minutes in air moving 1 m/sec
Stability (drift): < 0.1°C (0.18°F) per year

Relative Humidity Sensor:
Operation range: 0-100% RH, -40° to 70°C (-40° to 158°F)
Exposure to conditions below -20°C (-4°F) or above 95% RH may temporarily increase the maximum RH sensor error by an additional 1%
Accuracy: ±2.5% from 10 to 90% typical, to a maximum of ±3.5%.
Resolution: 0.03%
Response time (typical to 90%): 40 minute in air moving 1 m/sec with protective cap
Stability (drift): < 1% per year typical; hysteresis 1%

Operation range -40° to 70°C (-40° to 158°F)
Real-time clock ± 1 minute per month 0° to 50°C (32° to 122°F)
Battery 1/2 AA, 3.6 Volt lithium, user-replaceable (part # HP-B)
Battery life (typical use): 3 years with 1 minute or greater logging interval
Memory (non-volatile): 64K bytes memory (approx. 21,000 temperature and RH measurements)

ASA styrene polymer housing and mounting clamp; polypropylene protective cap; Buna-N o-ring(s)
U23-001, U23-002 only: ASA styrene polymer RH sensor cap; modified hydrophobic polyethersulfone membrane
Environmental rating: Electronics housing is NEMA 6P equivalent (tolerant of brief submergence)
Units with RH sensors are NEMA 4 equivalent (splash-resistant)
Launch modes: Immediate start; delayed start
Logging interval: Fixed-rate or multiple logging intervals, with up to 8 user-defined logging intervals and durations; logging intervals from 1 second to 18 hours (refer to HOBOware software manual)
Offload modes: Offload while logging; stop and offload
Battery indication: Battery voltage can be viewed in status screen and optionally logged in datafile. Low battery indication in datafile.
Weight: 57 g (1.5 oz)
Dimensions: Housing measures 10.2 × 3.8 cm (4.0 × 1.5 in.)

NIST Temperature Certificate available for additional charge

30 other products in the same category: