Update: February 9, 2015 Alas, another of these excellent units has bitten the dust. They simply don't last that long, even when the probe is protected from the elements. We originally bought two of them because they are designed so much better than other indoor-outdoor thermometers-humidity devices. And, for a couple of years, they worked liked a charm. However, like our first, our second unit's hygrometer has now failed--it reads 29% at all times. If you read the story at the end, you'll see that the first one failed last year, getting stuck at 15%. Very disappointing! Plus, there's a problem reaching the company-- I detail that at the end, too. ORIGINAL REVIEW As you can tell from my other reviews, we've been on a quest for a decent, accurate, easy to read indoor-outdoor thermometer with hygrometer (humidity reader). Every one we've tried has failed in particularly fundamental ways--screen hard to read, digits too small, too much superfluous nonsense, inaccurate, etc. Well, Extech has accomplished a minor miracle with this product. 1. Readable. You can see the digits from across the room. 2. Crisp display. They show up well even when the only light is in another room. 3. Accurate. The humidity and temperature readings are virtually identical when the probe sits by the base unit's air opening--off by only .1 or not at all--meaning the unit is incredibly accurate (finally we found one!). 4. Worry-free. There's no worrying about the batteries in an external unit. 5. Data-rich. Has min/max button. 6. Frustration-free. Battery compartment easy to open. Extech (check out their web site) is a company specializing in scientific and industrial applications and products and that translates into precision and usability for this instrument for the home. This product's data sheet even specifies its accuracy! "Accuracy: ±5%RH; ±1.8°F, ±1°C". Now, I'm hoping that they actually meant 5% and not 5 percentage *points*, a big difference! If the RH is 40%, then ±5% would be .40 * .05 or .02, so the accuracy would be between 38 and 42% . Alternatively, ±5 points would mean 35-45!! I think the first is more likely from what we've seen, but I suspect they hedging their bets and meant the second (±5 points). Given that the old one we replaced was off by at least 15 points, we'll take it! Readability, accuracy, and quality. This is the first one of these indoor/outdoor devices that we quickly knew was going to be a keeper. What's not to like? 1. Well, the cord is thick, which makes the window hard to close. OTOH, that should give it protection from being frayed away as happened with an old GE one we had. 2. As another reviewer said, a longer cord would be nice. (If you didn't realize it, this is a wired probe; not wireless.) Alas, they do not have a wireless unit--yet the good news is that means no battery draining of an outdoor unit that sits in the frigid cold. 3. Their web site lists a humidity calibration kit as an accessory for this, suggesting one could calibrate it. Alas, this unit does not have a humidity calibrator! Erroneous humidity readings are a standard problem in the indoor/outdoor products we've tried from other companies--and even in the ones we've liked and used for years (that are no longer being made). Extech's 445713 has none of those problems. 4. The reset button is right beside the min/max button, which means you run the risk of hitting it instead of the other and losing your data. 5. The probe is relatively large, meaning that it sits exposed to the elements (we got 99% humidity due to some rain). Other devices with wired probes use tiny ones that can be place inside the window tracks. This does have a mini-cage around it, though, which offers some protection. [June 14, 2014 note: We cut a cross-X in the bottom of an empty margarine tub and slipped the probe into that. Offers protection, yet is open to the air.] 6. Wish that temperature came first on the display! We're used to thinking about a day's temperature and its humidity--in that order. But all these are minor, very minor, quibbles compared to the glitches, defects, and deficiencies of the other indoor/outdoor thermometers out there that rendered them unusable and returned to Amazon. We're now browsing the Extech site to see if there are other products worth getting. They have a nifty temperature, humidity, barometer device that *records* the data onto an SD card for import into an Excel spreadsheet. Now, that's cool! Of course, even cooler, would be wirelessly transmitting to the computer! Highly recommended! NO LONGER! Caution: The hygrometers have a limited lifespan. TROUBLING DEVELOPMENTS Update: June 14, 2014 This was, without a doubt, the best of the indoor/outdoor thermometer/hygrometers we had found. Alas, though, after 2-3 years, the outdoor hygrometer part of one of our two units has failed! (And, now as noted at the outset, the other unit's humidity reader failed, too!) We noticed this when it was raining outside, yet it was reading 15% relative humidity for the outdoors! No way that can be the case! Even when the wired probe is brought indoors and left next to the indoor base unit reading 55%, the "outdoor" reading stays at 15%. (The temperatures, though, match exactly to the decimal point!) The hygrometer is not fully broken-- one can breathe on it and the RH will go up, but then it quickly returns to 15%. It's a shame as we had it protected from the elements inside an open air small margarine tub container. So, it's not water damage or anything like that. Our other unit is still working like a champ--NO LONGER TRUE, IT GOT STUCK AT 29%. I'll be contacting the company to see if they have a replacement probe. Depending upon what we find out, I may have to lower the rating. I did notice that someone else's hygrometer broke after only 8 months, which is troubling. CUSTOMER SERVICE IS MISSING IN ACTION I went to the Extech site. It lists their customer service phone # as 877-239-8324, but when called that leads to an error message "We're sorry, your call cannot be completed as dialed." Double-checked, tried again, same result! Great, so talking to someone is out. Are they still in business? One assumes so, but having an out of order customer service number is not a very good business practice. They claim, "Customer Service is our #1 priority" but without a working phone number... Aha! At the bottom of their home page, in greyed text is what could be the correct phone number. 877-439-8324. So, someone typed their company's phone number in wrong! Oops! Wishful thinking. That leads to a message: "The number you have dialed is not in service"!! Now, I am concerned about the status of the company. At this point, I've lowered the rating because of the unreliability of the devices--it was otherwise a great product. If they just offered replacement probes--that shouldn't be too hard to design--they'd be back at the top.
