Temtop S1 PM2.5 Air Quality Monitor & Indoor Thermometer

This is extremely accurate. You will not find a better monitor for PM2.5. The cheap Chinese brands you see on Temu and Amazon are super low quality and many are just fakes. Temtop is a leader in this category and can be trusted to bring you reliable air quality monitors. It uses a built-in micro laser particle sensor to accurately measure fine dust and smoke particles (PM2.5) down to 2.5 micrometers. This is the absolute best you will find under $50.

Vey impressed with this meter . I live in an area prone to wild fires and I have health probems so I always try to do whatever I can to keep the air in the house as clean as possible , not really knowing how well I'm doing compared to the outside air. This unit is accurate to within one point of the Fire Stations readings. I read reviews and saw a ideo of a guy that tested different one and he liked this one ,even though it was the least exensive . This particular meter has PM2.5 readings which is really the most important and a lot of the other one ,that cost way more did NOT . The display is easy to read . It came charged , I just had to turn it on Besides PM2,5 function it hass humidity,temp, Air Quality readings

Works as described well packaged, easy to use w/clear instructions and convenient magnet stand comes with. Basic and simple testing results as I needed.

It’s good and works, but I found that even in auto mode it sometimes takes awhile before it updates AQI and pm25. To get it to force update the numbers I have to press the cog button twice to switch between eco and auto, then it’ll update. It just makes it feel unreliable

Even on "auto" mode, I find that it doesn't automatically update to track real-time PM2.5 and AQI. As noted in other reviews, once I toggle to "eco" then back to "auto" mode, it usually refreshes immediately. I know it's accurate because we had a day of hazardous air quality here recently and the reading changed from indoors vs. outdoors. It's small, portable, has great battery life, and much better value than some of the other devices I've seen online.

I bought this when our area was experiencing a lot of smoke this summer - even a couple of 1000+ AQI days (yes, 1 thousand+). I mainly wanted to see what the AQI was inside our house even though we were running 2 HEPA air purifiers. I also tested this outside and found the readings were very close to the "official" readings. The only issue I had was when there was a rapid change in the AQI (low inside to high outside or near kitchen placement when cooking), then the reading became "stuck" at the higher reading. Quickly remedied though by just turning off then back back on)

Update #4: The company sent me another one so I could corroborate the readings of the unit I bought. I did several quick tests in various locations and in nearly all cases I got the same reading on both, or very close. However the photos show one case where the readings seemed to get stuck and after waiting about 40 minutes (note the times on the microwave) the readings were still different in this one test. The last photo was taken after I turned both devices off then back on, and in that case they settled on the same reading. Basically, the flaw with these units is that they will sometimes get stuck on an inaccurate reading… but in most cases if you turn it off then back on you will get a different and presumably more accurate reading. Overall I’d say these are accurate enough to be useful, as long as you don’t mind confirming the reading by turning the device off then back on. Update #3: I continue to have trouble with the device. It shows an accurate reading in some cases, but only shortly after it is turned on. Then it just fixates on that reading regardless of changing conditions. I have confirmed this issue repeatedly by turning it off and on after it gets stuck, and almost without exception it will settle on a much different reading after it is turned off and then back on. Meanwhile, the manufacturer has offered to send me a new device, which I do appreciate, and I will update my rating if they are able to follow through and if the replacement works better than the one I have now. Update #2: It kind of works but has a tendency to get stuck on readings a minute or two after you turn it on, and then the reading doesn't change even if you move it to a location where the air quality is obviously different. This can be confirmed by turning it off then back on, which will often cause it to reset to what is likely a more accurate reading. It does seem to respond to changes in air quality, so long as you turn it off then back on. The ECO (power-saving) mode doesn't work, or it is always on regardless of whether you turn it on or off. There is no change in behavior depending on whether you turn the power-saving mode on or off. Either way, it tends to get stuck on a reading, sometimes, a minute or two after you turn it on. But not always. Sometimes it won't get stuck until 15 minutes after you turn it on, sometimes it is responsive for a few hours, etc. Update: Still doesn't seem to be working. Today it was showing a PM2.5 reading of 22 in location #1, outside. I then moved it inside, to location #2. An hour later it still showed 22. I then turned it off and back on, and left it in location #2. It then read 15, and is staying at 14-15. So how did the PM2.5 decrease by 33% just because I turned it off and on? I didn't disturb the air in that area very much when I turned it off and then back on. I didn't waive it around or anything. So how could pushing a button twice change the PM2.5 by 33%? Original review: Received this item in the mail today. When I first turned it on, and for a few hours after that, the PM2.5 and AQI seemed quite plausible, and I figured the device was working well. A few hours after that, I looked at the device, and in the same location, on my nightstand, it was now reporting PM2.5 had increased by 10x and the AQI had gone from in the 30s to above 140. This is totally implausible. There has been no change in the environment that would explain this. All weather sites and other online sources report air quality readings consistent with what the device was showing earlier in the day. I tried moving the device outside, etc. Turning it off and on, and the readings are still implausible high. I have done no nearby cooking, showering, etc, or anything else that could have affected the device. Meanwhile, when I switch it to ECO mode, the PM2.5 continues to move up and down, even though this mode is supposed to only test PM2.5 once every 30 minutes. Earlier today it was working, but inexplicably the PM2.5 now fluctuates even when in ECO mode. And for what it's worth, the Amazon listing for this item says the company is "based in USA," but unsurprisingly, the device itself says it is made in China. Not that the Chinese are incapable of making anything good, but this particular Chinese manufacturer appears to have failed.

I thought this thing was broken, but it turns out my neighbor was burning stuff in their backyard. I thought there was no way the air quality could be so bad, it didn't match the iphone number for my location. Usually the air quality in the house is a bit better than what the iphone predicts outside. So it seems to work pretty well

It does seem to provide pretty accurate PM2.5 and air quality readings. At least, these jibed with the one-word weather descriptions of Accuweather, a weather forecasting service. But will still need to try it out more to ascertain if it’s really accurate over a spectrum of air quality conditions. As of the first series of readings though, it did well.

This air quality monitor is working perfectly fine. I have seen some comments saying that it is not stable but I have tested it in multiple scenarios and it is working perfectly fine. I have recently bought an air purifier. Before turning on the air purifier the AQI was around 85 in my room. After 10 minutes of running the air purifier at full speed the value dropped to 25. I also tried it in multiple places during multiple days and the values looked consistent. I think this is a genuine product. I am attaching a few images captured at different locations. The only problem I noticed is when we use it directly under the sunlight it is giving a lesser AQI value. I think they have also mentioned this point in their manual, saying that direct exposure to a light source can alter the values. That is the only issue I found with it but for internal use cases it is great and really content and the battery life is so good. I have been using it for almost one week and even a single bar has dropped on it. Just to clarify I have been only using it on and off for short durations to test the AQI. I haven't left it turned on but even with this I think the battery life is really good.

Estaba súper escéptico al comprar este producto por las reseñas que he visto. Algunas dicen que no le dura la batería. Otros que no es exacto. Otros que se traba y ya no mide más. Después de una semana de usarlo… la batería le ha durado impresionantemente mucho. Si lo considero sensible ya que sí marca diferencias cuando cambias de cuarto o cuando sales. Inclusive me lo he llevado a casas de amigos para medir en diferentes lugares y verdaderamente mide más contaminado en donde sí está más contaminado y también mide menos contaminado cuando ya tengo el purificador de aire prendido durante algún tiempo. Lo único que no me gusta tanto es que es más exacto cuando lo prendes y apagas porque. Vuelve a medir desde 0 pero bueno, al final mide y es lo que importa. Tiene un margen de error de más menos 5 y como dice en el instructivo: al final es un producto para medir en casa, no es profesional ni la herramienta más fina es para que te des una idea. Lo recomiendo ampliamente y le dejo las 5 estrellas para complementar tantos malos reviews con los que no estoy de acuerdo para nada. Update: Estoy aún más contento con el sensor porque me lo he estado llevando a diferentes lugares. Me lo traje a un lugar que es un bosque y el aire supuestamente está muy limpio y al llegar lo encendí y ciertamente lo marco limpio. Pero luego el vecino empezó a quemar basura y cosas (malamente) y al mirarlo subieron los niveles de 12 aqi a 140 aqi. Realmente funciona y sí reacciona en un rango de tiempo realmente rápido.

No sirve.

The product shows the AQI as described however the data is not real-time. The automatic mode is not usefull at all and manual mode refresh in half n hour.