HT607 Temperature Humidity Meter High Precision Digital Hygrometer with Ambient, Relative Humidity, Dew Point, Wet Bulb Thermometer, Min/Max Hold, LCD Backlight with Cover Protector

I got this to use as a calibration source for some mechanical hygrometers I want to test, to see if they even work at all. I need a portable unit to move around several buildings. This unit seems to work ok; I can't tell if it is accurate without setting up the tests, but after 30 minutes from out of the box and power-up, it was within a deg F of two other digital thermometers I have, and I've watched it track with temp changes up and down, maintaining the same relative differences with the other thermometers. It took a while for it to "settle down" to a temperature and RH; temp was several deg F off the other digital thermometers when I first turned it on, and took at least 10 minutes to stabilize the temp. It states +/-3F and +/-3%RH for the accuracy, so I guess it is operating within its design tolerances.Bottom line, it will probably do for calibrating my other analog hygrometers and proving whether they are working or not. Humidity is all relative, anyway.

It's largely a matter of faith as to whether any hygrometer is giving accurate readings. There are ways of calibrating them, but these aren't all that reliable for a variety of reasons, like the fact that calibrating at one humidity level doesn't guarantee accuracy at other humidity levels. That's due to the fact that errors are nonlinear (not always off by a constant amount). Errors can be small (or even zero) over some portion of the range and large at others. Most home calibration methods, like the salt method, calibrate at the high extreme of the range, when our concern may be for accuracy elsewhere in the range.That issue is a tough one to get around, but digital sensors seem to have gotten better. In any case, taking any value of relative humidity as the gospel truth is a questionable proposition.What I look for is patterns of change in displayed RH as the environment changes and, to some degree, concurrence among multiple indicators. That's where this unit seems to excel. It gives me a reading that tracks (notice I didn't say "agrees") with other devices I have and with changes in the environment, such as running the heat like crazy and/or running a humidifier. Also, repeat measurements are reasonably stable under unchanging conditions. So, the readings are reliable (notice I didn't say "accurate").The various bits of information the unit provides are convenient. For example, the dew point is sometimes more informative than the RH. This unit displays that.To sum up, even though I have no certainty that the readings this hygrometer gives me are precisely accurate RH values, I think it does about as well as you can expect in a consumer-grade product. It's consistent, easy to use, easy to read, compact, and affordable. If you need more than that, then you probably should be looking at laboratory equipment rather than something like this hygrometer. I like it and recommend it for most uses outside of a laboratory. It might even be fine in a lab but I'd need further validation tests to know that. In the real world, at affordable prices, in a convenient form factor, I think this is pretty much as good as it gets.

Advanced Tech Review:This is a pro grade product which measures the Humidity Levels not as Relative Humidity RH but as Humidity Ratio HR or GPP Grains Per Pound of Pressure. In water damage restoration this device tells us how much GPP or grains of moisture there is per pound of Air Mass (14 cubic feet of air) and the temperature as well. This data then tells us what equipment (air movers, Air Filtration Devices AFD, ventilators, Dehumidifiers (dehu), etc...to use and where to locate them to establish our dry bulb levels (driest point we need to reach). It also tells us Dew Point which tells us if we will have condensation issues. For the price you can not go wrong, the accuracy is excellent. I would buy 2 or 3 to have on hand if they are lost or stolen, no big deal :)

Edited….Never received it , tried to tell Amazon and they won’t allow me to say I didn’t get it for 3 days even though it says it was delivered.,……..I found it it was hidden in a stroller, seems to work good , looking forward to using it . Easy to use and read.

Very reliable equipment! Very accurated!

Very accurate and compact

A very handy device for indoor climate geeks. This is very accurate and compares favorably to professional models that cost much more.

Just received, out of the box the ambient room temperatures are off, reading 3-4 degrees too high. It's a meter, it's supposed to be reasonably accurate. It uses the ambient temperature to calculate the Dewpoint (the reason for buying the device) it sort of negates the reason for owning the device if that parameter is off.Based on the price, I didn't expect lab instrument accuracy, but within 2 degrees as specified would have been acceptable. However, I will keep the device and just keep in mind the DP reading will always be a bit higher elevated that what is actually present.