As an indoor grower, it’s important to accurately measure the temperature and humidity of your grow room or grow tent. That’s where grow room environmental controllers come in. Grow room controllers combine temperature controllers and dehumidifiers to eliminate the need for two separate devices. As a result, you save money by using an all-in-one unit and free up space in your grow room.

The hotter it is, the more moisture the air can hold; the cooler it is, the less moisture the air can hold. When the temp in a grow room drops, the humidity climbs and moisture condenses. If you notice that the thermostat keeps rising and your room is holding too much moisture, you may need to incorporate inline fans or air conditioners into your grow room.

You can be able to monitor the two parameters closely and know when either of the two is in excess or lower than normal.

The most popular Hygro-Thermometers are digitally made with a large display. However, not all units will perform excellently.

After detailed research and analysis of features, we found the following five top products for your grow room.

Product Temperature
Range (°F)
Humidity
Range
Price
ThermoPro TP50 -58 to 158 30% to 60%
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Habor -32 to 122 20% to 95%
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ThermoPro TP63 -31 to 158 30% to 80%
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Ambient Weather WS-10-X4 -40 to 140 10% to 99%
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Bjerg Instruments Antique -20 to 120 10% to 99%
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Top 5 Best Temp and Humidity Controllers

#1 ThermoPro TP50 Hygrometer Indoor Thermometer

The TP50 is a small, mobile, accurate temperature and humidity reader with a wide temperature range compared to conventional units.

This unit delivers precise and professional readings of the humidity as well as the temp of your indoor grow space.

The controller comes equipped with the ability to provide you with the environmental conditions including daily highs as well as lows, of your growing environment.

What is truly impressive about the TP50 is the large digits digital readout. It clearly displays current humidity, current temp, comfort level, and min/max humidity and temperature.

The humidity comfort level feature tells you when the room is dry, wet or normal. All the tools combined allow for the optimization of your chosen settings.

The back of the controller is fitted with a Celsius and Fahrenheit toggle button, a magnet mount, a battery compartment, and a retractable stand.

The smart design has superior humidity accuracy. You have +/-2 percent from 30 to 80 percent, and +/-3 percent from 10 to 30 percent and 80 to 99 percent.

Things We Like:

  • Portability is at a premium with TP50
  • Displays daily lows and highs for temperature and humidity
  • Large digits display allows for easy readings
  • Easy to switch from Fahrenheit to Celsius with the toggle switch
  • Multiple mounting techniques are available
  • Comfort level indicator allows for superior optimization

Things We Didn’t Like:

  • May receive a defective unit that may malfunction

#2 Habor Digital Hygrometer Indoor Thermometer

Do you feel wet or dry whenever you are in your grow room? You need the Habor Digital Hygrometer Indoor Thermometer to know the temperature and humidity levels.

Measuring 2.3 inches by 1.8 inches, the unit is extremely portable. It is almost the same size as an egg. It is also super easy to install.

You’ve got more than one mounting options. You can choose to use the wall hanging design, table standing method, or mount with the magnet attachment feature.

This portable controller features twenty four highly sensitive vents that provide a fast response/detection time of ten seconds. It always provides accurate and updated readings.

Habor incorporated wide measuring scale. The humidity scale ranges from 20 to 95 percent, while the high temperature scale ranges from 32.0 to 122.0 degrees Fahrenheit.

Unlike conventional units, this portable controller comes with a comfort level indicator, which shows normal, uncomfortable, and comfortable conditions in your grow room.

Even though it is small in size, this unit has a simple digital readout. You can use the function button to switch the grow room temperature units (degree Fahrenheit/degree Celsius).

Things We Like:

  • Extremely portable temp and humid controller
  • Fast response/detection time improves accuracy
  • Comfort level indicator alerts you of abnormal conditions in your grow room
  • More than one mounting options for convenience
  • Function button allows you to switch temperature units at ease
  • Comes equipped with CR2 batteries

Things We Didn’t Like:

  • Provided batteries have a short lifespan

#3 ThermoPro TP63 Digital Wireless Hygrometer and Thermometer

If for any reason the TP50 didn’t impress you, you can try out the TP63. It is one of the finest from ThermoPro.

In the package contents, you should expect to find the remote receiver, the remote transmitter, 1 year warranty card, user manual, power plug, AC wall adapter, and two AAA batteries.

The unit is remarkably easy to configure. All you have to do is feed the batteries into the battery compartment.

The unit runs on autopilot and will turn on and start searching for a remote transmitter to connect. The TP63 comes with a completely rechargeable remote transmitter.

On the display, the device will show the outdoor temp and trend arrows as well as the indoor temperature, humidity, and trend arrows.

On the back of the unit, you will find the channel/sync button, the Fahrenheit/Celsius button, as well as the max/min and clear button.

Tapping the channel button will toggle through channels one, two, and three. You can cancel the channel mode by tapping the channel button until the circular arrow disappears.

Things We Like:

  • Comes with a waterproof design that won’t be affected by humid conditions
  • Backlit readout gives clear readings of outdoor and indoor temp as well as humidity
  • Wireless remote has a superior range of up to 200 feet
  • Has a reliable temperature accuracy of +/-2.0 degrees Fahrenheit
  • Completely rechargeable transmitter design is convenient
  • Trend arrows allow for easy adjustments
  • Can sync up to three remote sensors

Things We Didn’t Like:

  • Transmitter recharging time not stated by the manufacturer

#4 Ambient Weather WS-10-X4 Thermo-Hygrometer

Are you looking for a simple to use and reasonably priced temp and humidity controller for your grow room? Look no further than the WS-10-X4 from Ambient Weather.

Out of the box, you get four remote sensors for superior temperature and humidity detection and the console.

The console comes with a large digital timer readout that clearly displays the temperature in degrees Fahrenheit and humidity in percentage.

The console is also programmed with visual and audible alarms that alert you when the humidity and temperature levels are exceeded. Also, you’ve got preset min/max alarm settings.

What we found really impressive about this unit is the scroll mode. It allows you to view through the various available channels without the need of pressing any buttons.

The scroll mode displays all the detected sensors in 5-second intervals. You can also fine tune the device by using the optional temp and humidity calibration technology.

This is a super detection system on its own, it is engineered to support up to eight wireless sensors. This allows you to monitor more than one grow room.

Things We Like:

  • Ideal for indoor gardening as well as outdoor use
  • Each sensor is automatically displayed in scroll mode
  • The large readout is super easy to read and decipher
  • Superior transmission of up to a hundred feet
  • Remote sensors come with dip switches for easy channel selection

Things We Didn’t Like:

  • Sensors may generate an intermittent signal

#5 Bjerg Instruments Antique Indoor/Outdoor Thermometer & Hygrometer

Do you want something unique apart from the usual digital controllers? Look no further than the Bjerg Instruments.

This clock-like temp and humidity monitor is available in five finishes, including the antique copper, brass, bronze, copper, and satin nickel finish.

Has an easy analog readout. The larger scale (-20 to 120) is the Fahrenheit scale, and the inner small scale (-30 to 50) is the Celsius scale.

The humidity scale is located at the bottom, and it ranges from 0 to 100 percent with equal increments of 10 percent.

It has a clear plastic optical shadow resistant lens that is highly durable. The body is made of steel construction that is scratch resistant.

The unit comes preset from the manufacturer. Unless you accidentally drop it during unboxing, it won’t require any setting.

Unlike digital controllers, this analog model will take a considerable amount of time to adjust to the conditions of your growing environment.

Things We Like:

  • Adds an antique look to the interior of your grow room
  • Large diameter provides a clear view of the pointer
  • Plastic optical shadow resistant lens allows for easy readings
  • Steel construction is highly durable
  • Easy to adjust settings with a flat blade screwdriver

Things We Didn’t Like:

  • May take time to adjust to the conditions of your grow space

How to choose Temp and Humidity Controller for Grow room

Temperature and humidity control in a system relies on sensors for measuring temperature and humidity changes in the atmosphere of your grow room.

The objective is to bring the load to its preferred humidity and temperature set points as accurately and quickly as possible.

Here are a few things you have to consider:

Think of Your Application

Think about the features of your application before looking at what different controllers can offer you.

You need to think of how accurately or precisely you need temperature and humidity of your growing environment controlled. In some cases, you may even want to control the co2 levels in your grow room as well and will want a device that will give you the measurements you need. If your grow space is prone to overheating, you may need to add an air conditioning unit into the mix as well.

You have to know the absolute temperature limits that you have to maintain before the intervention.

Analog vs. Digital

Analog controllers use metal springs to detect climate changes in your grow room. The spring may loosen or tighten with respect to the temperature or humidity levels.

Some analog devices use natural or synthetic hair to detect climate changes in your growing environment.

Models that use natural or synthetic hair are more accurate. They also need little to no maintenance.

On the other hand, digital models use modern technology (sensors) for temperature and humidity detection.

A feature unique to digital controllers is the digital readout, which may need calibration and is much easier to read.

An analog unit is a low-cost way of monitoring your grow room. The easier to read digital version displays relative humidity as well as the indoor and outdoor temperature.

Temperature and Humidity Range

The most important feature of any Hygro-thermometer is the temp and humidity range. This depends on the type of sensors.

High performing sensors are important to the performance of any climate control system. Most controllers vary enormously with respect to their sensors. Some of these devices will include co2 monitors to keep an eye on the carbon dioxide levels in the room during various pints of humidity.

Their initial accuracy, ability to operate within different environments and long-term accuracy determine their efficiency.

The outdoor temperature limits of most units may range from -20°F to 158°F, while the indoor limits may range from -4°F to 158°F. The humidity limits may range from 10% to 99%, 10% to 95, or 30% to 80% and so on.

When selecting a Hygro-thermometer, check to confirm if the scale reads in Celsius or Fahrenheit or a combination of both Celsius and Fahrenheit.

The accuracy of analog units may not be difficult to establish because there are small markings in between the ten-fold points.

Digital controllers give direct humidity and temperature readings but must be calibrated for humidity and temperature range in which they are used.

Digital designs are both accurate and reliable, but it is important to buy a high-quality model. Consider models with superior accuracy, such as +/-2.7°F (temp) and +/-5% (humidity).

Special Features

There are a few special features you can consider. The first one is the comfort level indicator. This feature helps you to know when the conditions are normal, uncomfortable, or comfortable.

The second thing you should look for is multiple mounting options, including hanging, table standing, and magnet attachment.

The third thing you can consider is multiple channels. Some high-end controllers come with four remote sensors and the readout displays four separate readings.

The fourth special feature is the transmission range. The best models have a transmission range of up to three hundred feet line of sight, and a hundred feet under most conditions.

Final Words

It is important to realize that the indoor temperature, combined with your grow room relative humidity level, has a strong impact on the moisture content of your cannabis plants.

Knowing and controlling the climate in your grow room is the best way to keep your plants in good condition. The right climate controller will give you peace of mind that your plants are in good hands.

Your growing environment relative humidity level should be in a range of 30% to 50% at 75°F. A humidity level of 40% would be ideal.

Optimal levels allow you to grow indoors without the fear of your plants being too wet or too dry. So, invest in a high-quality temp and humidity controller for grow room. It’s also important to remember that you need everything in your grow room to work together harmoniously. That means making sure that your grow room controller works well with your grow lights, hydroponics, and that everything is customizable so that as your grow operation changes, you can still continue to use your equipment.

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