Extech RH390 Hygro Thermometer Psychrometer

Name: Extech RH390 Hygro Thermometer Psychrometer
Price: 284.41 USD
Availability: InStock
Rating: 4.2 (24 reviews)

Curated from 24 real Reddit conversations

Refreshed on: January 26, 2025

Extech RH390 Hygro Thermometer Psychrometer

Brand: Extech

Price: $284

Snoop Score:

4.2

Sentiment

2.5

Popularity

0.3

Technical

6.7

Buy on Amazon for $284 See All Hygro Thermometers Reviews

As an Amazon Associate, I earn from qualifying purchases.

Snoop's Take

The Extech RH390 Precision Dual Display Hygro Thermometer Psychrometer is a specialized device designed to measure both humidity and temperature with precision. With a dual display feature, it provides real-time readings for humidity and temperature or other combinations like dew point and wet bulb, making it useful for a variety of applications. Consumer feedback on the Extech RH390 indicates a mixed reception, with some users appreciating its simplicity, as one reviewer noted, "We have the RH529B, a pretty simple unit." However, there are significant concerns regarding the accuracy and reliability of the thermometer, with users reporting issues such as faulty readings and suggesting, "the fix is don't use analog hygrometers or thermometers. They're nowhere near as accurate or precise as they should be." Given the feedback highlighting both its ease of use and concerns about reliability, potential buyers should weigh these factors carefully. While the Extech RH390 offers useful features for monitoring environmental conditions, it may not be the best choice for users requiring highly precise measurements.

Not for you? Check out our other rated Hygro Thermometers

We have the RH529B, a pretty simple unit.
Positive Feedback

The thermometer is trash, you want a digital one.
Negative Feedback

4.2

Extech RH390 Hygro Thermometer Psychrometer

Buy on Amazon for $284

Reptile Habitat Monitoring

6 / 10

Amphibian Enclosure Management

6 / 10

Greenhouse Climate Control

4 / 10

Laboratory and Educational Settings

4 / 10

See how this compares to all Hygro Thermometers

What it does well!

Key strengths users can’t stop talking about.

Extech RH529B is appreciated for simplicity

“We have the RH529B, a pretty simple unit.”➕

Where it needs some work!

Areas to watch—feedback on possible improvements.

Thermometer is not recommended

“The thermometer is trash, you want a digital one.”➕

“Thermometer: nope use a digital one not a analog.”➕

Thermometer is not reliable for accurate readings

“the thermometers in the tank, top and bottom, both say the whole tank is in the mid 80's.”➕

“I am slightly concerned the sensor is just faulty since I bought an open box unit on ebay.”➕

Analog hygrometers are less accurate and precise

“The fix is don't use analog hygrometers or thermometers. They're nowhere near as accurate or precise as they should be.”➕

Digital devices can be faulty and require more maintenance

“Digital devices are ALWAYS going to be faulty and require MORE maintenance than any analog device.”➕

Compare On All Talked About Dimensions

Product Name	Price	Score	See Details	Buy Now
Triplett RHT22 Digital Indoor Hygro-Thermometer	$38	7.6	Details	Buy
ACTIVE AIR ActiveAir Hygro-Thermometer	$16	5.9	Details	Buy
Triplett RHT70 Hygro-Thermometer and Infrared Thermometer	$150	5.8	Details	Buy
Extech RHT510 Hygro-Thermometer Psychrometer	$142	4.6	Details	Buy
Extech RH390 Hygro Thermometer Psychrometer	$284	4.2	Details	Buy
Extech CTH10A Radio Controlled Hygro-Thermometer Clock	$88	3.5	Details	Buy
Extech RH490 Hygro-Thermometer	$551	2.0	Details	Buy
Extech 445713 Big Digit Indoor/Outdoor Hygro-Thermometer	$59	1.6	Details	Buy
szdealhola 145mm Dial Stainless Steel Wall Mount Thermometer	$22	0.9	Details	Buy

Core Power Plays

The specs and strengths that make it shine.

Comparison of different monitor brands and their features

“Ideally the thermometer would have convenient logging capabilities and/or computer connection in a convenient way to avoid the operator having to do more data entry.”➕

“Last place I worked had one that would text you if it got out of a set range.”➕

“I looked briefly at those, but was unimpressed that I couldn't find basic accuracy listed on their web site for the models I checked.”➕

Buyer’s Cheat Sheet

What to check before you click ‘Add to Cart.’

Discussion about ideal temperature and humidity levels for tanks

“Your average temps are too low. Try to heat it up a little more.”➕

“I feel like when I adjust the heat, it makes the whole tank the same temperature in the 80s.”➕

Discussion about ideal humidity levels and their impact

“I fixed the humidity problem without breaking the bank.”➕

“Lower humidity is more comfortable for me, meaning lower utility bills.”➕

“If that gets turned off, it gets easily into the 60-65 range even with the AC running.”➕

“Sometimes 70s if two people showered and were boiling water and it was humid outside.”➕

Discussion on calibration methods for hygrometers

“Disk monitors are only useless if you don't know how to calibrate them.”➕

Discussion about finding reliable thermometers

“AcuRite seems to be the go-to for regular thermometers.”➕

“I think the AcuRite, Xiaomi and Zigbee have more accurate sensors, but it's always nice to have other options.”➕

“does that mean AccuRite is what you recommend?”➕

“thanks for posting this.”➕

Extech RH390 Hygro Thermometer Psychrometer

Curated from 24 real Reddit conversations

Extech RH390 Hygro Thermometer Psychrometer

Snoop's Take

Extech RH390 Hygro Thermometer Psychrometer

Reptile Habitat Monitoring

Amphibian Enclosure Management

Greenhouse Climate Control

Laboratory and Educational Settings

What it does well!

Where it needs some work!

Compare On All Talked About Dimensions

Core Power Plays

Buyer’s Cheat Sheet

You May Also Like

Explore more Categories