Active Air Hygro-Thermometer (Small)

The Active Air Hygro-Thermometer (Small) is a compact indoor/outdoor combo instrument that displays current temperature and relative humidity on a single large screen. A wired remote probe lets you monitor two locations at the same time, and built-in high/low memory captures peak readings for both temperature and humidity so you can review the full swing of your grow-room environment between check-ins.

Active Air Hygro-Thermometer (Small) Specifications

All specification values below are sourced from the manufacturer product documentation for model HGIOHT.

Why Choose the Active Air Hygro-Thermometer (Small)

Indoor growers need reliable environmental data without cluttering the grow space with multiple instruments. The Active Air Hygro-Thermometer (Small) addresses this by combining a humidity sensor and a thermometer in one compact housing built to hold up in the damp, warm conditions typical of enclosed grow rooms.

• Dual-parameter readout: Reads current temperature and relative humidity simultaneously on a single large display, so one glance gives you the full picture.
• Two-location monitoring with remote probe: The included wired probe lets you place the sensor inside your canopy while the main unit mounts on the tent wall, or monitor inside and outside the tent at the same time.
• High/low memory: Records the peak and trough values for both temperature and humidity. You can check the overnight swing without having to be present during the dark cycle.
• Built for grow-room conditions: The housing is described by the manufacturer as made of sturdy materials suited to the climate of an indoor grow room — higher humidity and temperature swings than a typical household environment.
• Compact size: At approximately 1 lb, this is a small-footprint tool that fits in tents, cabinets, and dedicated grow rooms without taking up meaningful space.

Best Uses for the Active Air Hygro-Thermometer (Small)

This instrument is straightforward to place anywhere you need an ongoing record of temperature and humidity. Common applications in indoor cultivation include:

• Grow tent environment monitoring: Mount on the inside tent wall to track the ambient conditions your plants are experiencing throughout the photoperiod and dark cycle.
• VPD spot-checks: Knowing both temperature and relative humidity at canopy level is the starting point for calculating vapor pressure deficit. Use the remote probe at canopy height and the main unit at a reference point higher in the tent.
• Overnight climate review: The high/low memory function makes it practical to check how far temperature dropped or humidity climbed during the night period without configuring a data logger.
• Propagation and clone areas: Cuttings and seedlings have tighter humidity requirements than mature plants. Placing this unit in a propagation dome or humidity tent lets you confirm the environment stays within range.
• Drying and curing rooms: After harvest, the same 60 degrees F / 60 percent RH targets used for drying are easy to track with a unit that records highs and lows between checks.
• Multi-zone comparisons: Use the remote probe in one zone and the onboard sensor in another to compare two areas of the same room side-by-side on a single display.

For general grow-room maintenance, keeping a cleaning solution like Alchemist 99.9% isopropyl alcohol on hand makes it easy to wipe down probe contacts and sensor housings between grows to prevent residue buildup. Similarly, a spare razor blade is a useful companion for any tool maintenance or trimming tasks in the same grow space.

Sources & Further Reading