AC Infinity VPD Thermometer

AC Infinity VPD Thermometer

Measure leaf temperature for more accurate VPD calculations

The AC Infinity VPD Thermometer is a handheld infrared measurement tool designed to help growers establish the correct Leaf Offset for use with AC Infinity environmental controllers.

Its primary purpose is not general grow room climate monitoring. Instead, it measures the temperature of the plant leaf and compares this with ambient conditions, giving growers the information needed to improve the accuracy of their controller’s VPD calculations.

Why leaf temperature matters

An environmental controller measures the temperature of the surrounding air, but the temperature of the plant leaf can be different.

This difference is important when calculating plant VPD.

AC Infinity controllers allow growers to enter a Leaf Offset, which accounts for the difference between ambient air temperature and actual leaf temperature.

For example, if the plant leaf is cooler than the surrounding air, that difference can be entered into the controller as the Leaf Offset. The controller can then incorporate it into its VPD calculations.

Infrared leaf temperature measurement

The VPD Thermometer uses infrared technology to measure leaf surface temperature without physical contact.

A 12-point laser guide helps indicate the measurement area, allowing growers to take representative readings from the plant canopy.

This makes checking leaf temperature quick and straightforward without having to attach sensors directly to the plant.

Ambient environmental measurements

Alongside leaf temperature, the VPD Thermometer measures and displays:

• Ambient air temperature
• Relative humidity
• Air VPD
• Leaf temperature
• Leaf VPD

Having this information available on one handheld device allows the grower to compare ambient and leaf temperatures and establish the appropriate Leaf Offset.

Using Leaf Offset with AC Infinity controllers

Once leaf and ambient temperatures have been measured, the difference can be entered as the Leaf Offset within a compatible AC Infinity controller or the AC Infinity app.

This helps the controller calculate VPD using a more representative leaf temperature rather than relying solely on ambient air temperature.

The process is straightforward:

• Measure the plant leaf temperature.
• Compare it with the ambient air temperature.
• Calculate the temperature difference.
• Enter the difference as the Leaf Offset in the AC Infinity controller or app.
• Repeat measurements periodically as the crop develops.

Leaf temperature can change throughout the growth cycle, so checking the offset periodically allows the controller’s VPD calculation to be refined as plant and environmental conditions change.

Adjustable measurement settings

The thermometer includes settings for:

• Emissivity
• °C / °F
• Ambient temperature calibration
• Relative humidity calibration
• Leaf temperature calibration

These settings allow readings to be adjusted where necessary for more accurate measurement.

Additional functions

The VPD Thermometer also provides:

• Previous five reading history
• 12-point laser on/off control
• Factory reset
• Individual setting reset
• Automatic power-off after 20 seconds of inactivity

These functions make it a practical handheld companion for growers using VPD-based environmental control.

Key benefits

• Measures plant leaf temperature
• Infrared non-contact measurement
• 12-point laser guide
• Measures ambient temperature and relative humidity
• Displays Air VPD and Leaf VPD
• Helps calculate Leaf Offset
• Improves VPD calculations in compatible AC Infinity controllers
• Leaf Offset can be rechecked throughout the grow cycle
• Temperature, humidity and leaf temperature calibration
• Stores the previous five readings
• Portable handheld design
• Designed for growers using VPD-based environmental control

Important information

• Primarily designed to establish Leaf Offset for VPD calculations
• Does not connect directly to a UIS controller
• Leaf Offset is entered separately into the compatible controller or AC Infinity app
• It should not be positioned as a tool for detecting hotspots, humidity pockets or airflow efficiency