HT-4000 Thermo-Hygrometer

The HT-4000 is a stand-alone thermo-hygrometer that has the same fast acclimating RH/T sensor found in our popular Navigator Pro and TotalCheck 3-in-1 moisture meters. For contractors who prefer having separate meters to one combination meter, the HT-4000 is the perfect solution.


Where to Buy

Product Features

  • Bright, clear digital display.
  • Relative Humidity Range: 0% - 100%, 
  • Temperature Range: -40°F - 255°F (-40°C - 124°C).
  • Dew Point Range: -40°F - 176°F (-40°C - 80°C).
  • GPP Range: 0.1 - 3820 GPP (Grains Per Pound).
  • GPK Range: 0.01 - 545 GPK (Grains Per Kilogram).
  • Vapor Pressure Range: 0 - 7 PSI (Pounds Per Square Inch).
  • Vapor Pressure Range: 0 - 47 KPA (Kilopascals).
  • Built-in back-light makes reading in dark places a cinch.
  • Auto shut-off timer saves battery life.
  • Reading HOLD Feature.
  • Size: 8 ½” x 3 3/8” x 1 ¾”.
  • Weight: 11 oz.
  • Rugged construction ensures years of reliable use.
  • Sturdy plastic carrying case.
  • 9V battery.
  • 1-year warranty.

Individual Instrument: Includes meter, (1) RH/T-S1 sensor, and carrying case. Order as HT-4000W/CS. (Price: $545.00)

HT-4000 Thermo-Hygrometer Accessories:


Relative Humidity Test Kit

The relative humidity test kit is great for testing the accuracy of our detachable RH/T-S1 and RH/T-S3 relative humidity sensors. The air inside the test kit bottle is controlled by a salt solution, which keeps the relative humidity constant. The kit is available with either 33% or 75% relative humidity (Order asRH/TK/33 and RH/TK/75 respectively).

RH/TK/33 (Price: $125.00)

RH/TK/75 (Price: $125.00)



Detachable relative humidity/temperature sensor that is included with Navigator Pro and HT-4000. Can be used to obtain ambient RH/T readings. Order individually or in packs of 5 as RH/T-S1/5.

Order as:

RH/T/S1 (Price: $80.00)

RH/T/S1/5 (Price: $400.00)



Extension cable that connects to the RH/T-S1 and RH/T-S3, allowing you to easily view your meter’s screen while performing tests in hard to reach areas.

(Price: $55.50)

HT-4000 Thermo-Hygrometer Electrodes:

Delmhorst offers a wide assortment of electrodes known throughout the industry for their durability. All Delmhorst electrodes fit any Delmhorst moisture meter. Below are electrodes that are typically used for this model:

Manuals & Training

Owner's Manual

Product Manual

Download Manual (pdf)


Relative Humidity Sensor Behavior and Care

Download Whitepaper (pdf)

Online Learning

Interactive Training Course

Click here to start learning


Moisture Meters 101 Guide

Finding the right kind of moisture detection equipment to meet your needs is a huge part of being able to anticipate how moisture conditions can affect your work.


Download the Complete Guide to Measuring Moisture in Restoration

Measuring Moisture in Restoration

Knowing the exact location and extent of moisture in a building is essential knowledge for restoration efforts. The full applications of moisture meters in restoration projects are described in this eGuide.


For more information, view our complete list of 
Moisture Meter Resources