Extech RH200W-T Wireless Hygro-Thermometer Transmitter for RH200W

I have been using this for over two months now. My primary purpose for purchasing this unit (along with an extra transmitter) was to monitor the humidity level in my guitar cases. Keeping track of outdoor conditions was an afterthought. I am comparing this unit alongside a Traceable #4380 unit from the Control Company in Texas. My initial impression of this product is that it reflects typical Extech quality, which has always been good. But a few characteristics have their drawbacks.First of all, despite what the heading in the ad says – “Extech RH200W Wireless Indoor/Outdoor Hygro-Thermometer Indicator” – this NOT designed for outdoor use. In fact, the directions say, “Avoid placing the sensor in direct sunlight or INCLEMENT WEATHER.” I spoke to a tech representative from Extech on this. He explained that the transmitters have a protection rating of IP54, which means that they are not dust-tight and exposure to direct precipitation will render them inoperable at some point. So if you are looking for something to use on an RV or any place where the transmitters will get wet, or in a dusty environment, this unit is not for you. Incidentally, the Extech website lists this as an INDOOR unit. The description in the Extech site says “Connect up to 8 Wireless Transmitters to Remotely Measure INDOOR Temperature/Humidity.” So it would appear that the mistake in the ad heading appears to be just Amazon, not Extech.Amazon should correct the listing. I spoke to someone at Amazon about this but I suppose my message fell on deaf ears.I also agree with what some others have said about the shape of the transmitters. Whoever thought it was a good idea to have a contour on the back of the case where there is a keyhole slot for mounting should rethink their idea.As far as accuracy, I consider it okay. It reads within a degree or two of the ambient temperature and the remote transmitters read pretty close to that. So it’s usually with 3 – 4 degrees maximum error depending on the sensor. The humidity readings are usually within 3%-4%. Close enough for my needs.The Traceable unit has an edge in a few areas; the transmitters (it can link up to three) are in fact weatherproof, have their own digital display, and they also have a removable desk stand as well as a mounting clip which can be attached to a wall or object using either screws or by using the provided Velcro strips. I ended up using the Traceable units for the guitar cases due to the ease of mounting.The Extech RH200W is a decent unit which has the capability to link to and scan up to eight transmitters if you need that many provided that you are looking for something to monitor indoor conditions. However, due to the issues I mentioned, I’m giving it four stars. If you don’t need eight transmitters and are looking for truly weatherproof and more accurate equipment, I highly recommend the Traceable unit – it’s worth the extra few dollars.For what it is worth, since I was beyond the return period, I went ahead and mounted one of the Extech sensors outdoors (where it can’t get rained on directly) to see how long it lasts. I will let you all know when it fails.

The instructions that came with this are totally confusing. No hardware is provided to mount this so it is apparently intended to lie flat. The readings are way off from those of other units which have proven accurate.

When this arrived I handed it over to my husband to get it up and running. He said it was easy enough to install, ours did come with all the batteries, I see that other reviewers only received 4 of the 6 needed, that is not good quality control in the manufacturing plant. He had no issues understanding the directions and liked that you can calibrate it. We have another brand of something very similar to this, and we have both noticed that THIS Extech RH200W is running circles around the other one as far as being closer to the actual temp and humidity. Out here in the desert we like to know what the temp is BEFORE we open the door. It seems to be right on and my husband is really enjoying the large readout that he can see from across the room. As far as attaching the sensor that is outdoors, he just has ours sitting in a shaded area of a post, he wants to put it up on a wall and will once he digs out something to screw into the wall, as others have said, it would be nice if they would of included this in with the item so you had a complete, ready to go unit and didn't have to go digging or purchase the hardware to do so. But all in all he is very pleased with the item.

I've owned other indoor/outdoor wireless thermometers. However, none have a large display, a backlight feature or, importantly an indoor/outdoor humidity readout. The Extech RH200W Wireless Indoor/Outdoor Hygro-Thermometer Indicator has all of these things.The Extech RH200W Wireless Indoor/Outdoor Hygro-Thermometer Indicator has a main base unit with display. It can read the temperature and humidity from its own sensors (e.g. the indoor temperature and humidity) and from up to eight external sensors that can be mounted outdoors or in other rooms. It measures temperature and humidity trends (up, down, no change,) it shows comfort levels with an icon and has a memory function.The unit that I received shipped with one base unit and one sensor. The base unit can be hung on the wall or it can use a built in desk stand. The oddly shaped remote sensor can be hung outside. Everything runs on AA batteries that are supplied.I mentioned that the remote sensor is oddly shaped. By that I mean that the back is curved. This may offer some esthetic appeal, but it makes the sensor harder to hang and less stable. Although, I tried my best to secure it with a hanger, I am sure that a blast of wind from a squall will knock it right off its mountings. Why Extech thought that a curved back for something intended to be hung outside was a good idea is beyond me.Speaking of mounting, it would have been nice if Extech had thrown in the mounting hardware with the product. I found what I needed in my parts bin, but why was it necessary for me to even look?Another concern is that the base unit cycles through all eight sensors each and every time--even if there is just one sensor attached. It would have been better for the base unit to bypass the channels that have no sensors.Despite some of these qualms, the Extech RH200W Wireless Indoor/Outdoor Hygro-Thermometer Indicator is a really useful tool. It's accuracy seems reasonable out of the box, but if you need better it can be calibrated. The large display, temperature and humidity readings and backlight make this a worthwhile investment to keep an eye on your indoor and outdoor conditions.