Psychrometer with No Mercury Herter 4012 — Safe and Precise Humidity Measurement

The Herter 4012 is a professional, handheld psychrometer designed for fast, reliable humidity assessment without hazardous substances. Its mercury‑free design uses twin spirit thermometers to capture wet‑bulb and dry‑bulb temperatures, allowing you to calculate relative humidity and dew point with confidence in the field or the laboratory. Robust, portable and battery‑free, it delivers dependable readings wherever you work—HVAC sites, greenhouses, warehouses, classrooms or outdoor surveys—making it an ideal choice available at Stratosens.com.

Key Benefits and Applications

• Mercury‑free safety: Spirit‑filled thermometers eliminate mercury risks for a safer, environmentally responsible workflow in schools, laboratories and on‑site inspections.
• Battery‑free reliability: Purely mechanical operation ensures consistent performance without charging, replacements or electronic drift, perfect for remote locations.
• Trusted psychrometric accuracy: Dual wet‑bulb and dry‑bulb readings provide a proven path to precise relative humidity and dew point calculations across diverse climates.
• Built for field and lab: A rugged frame and clear Celsius scales make it easy to transport, read and use in HVAC commissioning, agricultural monitoring, storage control and educational demonstrations.
• Fast, repeatable readings: Stable thermometer columns and an efficient airflow design help achieve quick equilibrium for repeatable measurements during routine checks.
• Low maintenance: Simple components, a replaceable wet‑bulb wick and the use of distilled water keep upkeep minimal and cost‑effective.

Featured technical specifications

• Measurement principle: Dual thermometer psychrometry capturing dry‑bulb and wet‑bulb temperatures to determine relative humidity and dew point using standard psychrometric methods.
• Thermometer fluid: Spirit‑filled, mercury‑free columns designed for safe handling and transport.
• Scale and units: Clearly graduated Celsius scale for direct temperature reading in °C, aligned with International System usage.
• Airflow during measurement: Instrument designed to ensure steady airflow across the wet bulb for accurate psychrometric readings when operated correctly.
• Wet‑bulb wick: Absorbent wick maintains a consistent moisture film on the wet bulb; use with distilled water for best results.
• Calculated parameters: Relative humidity and dew point derived from wet‑bulb and dry‑bulb temperatures using psychrometric charts or tables.
• Construction: Durable, field‑ready body with protected thermometer mounts for stability and easy viewing.
• Power requirements: None required; fully mechanical operation for dependable performance in any environment.
• Typical use environments: HVAC diagnostics, meteorology fieldwork, horticulture and greenhouse control, museums and archives, storage and logistics, education and training.
• Care and maintenance: Periodic wick replacement and cleaning with distilled water recommended to preserve measurement quality.

Why this psychrometer is the perfect choice

Choose the Herter 4012 at Stratosens.com to combine mercury‑free safety, proven psychrometric accuracy and go‑anywhere reliability in one compact instrument. Our focus on precision tools means you get a robust, ready‑to‑work solution that simplifies humidity control tasks, supports compliance with safer materials policies and delivers consistent results across your projects.