A1C

With all the smoke from the forest fires it’s been great to be able to keep an eye on our indoor air quality, and when it drops to know and quickly look for the cause, a window left open somewhere. Helps us see how effective our air filters are and when we need to replace them as well.

Price to performance is quite hard to beat, It got name brand sensors just like the rest of the air quality monitors.CO2 sensors can be tested by having it outside and seeing if it hits around 400ppm and blowing onto the sensor until it hits 3000ish and stops climbing. I tested mine, indoors with windows open it was around 580 and blowing on it, it hit 3160 and stop climbing.Temps and humidity is ballpark like 1-5% ish compared to my traceable thermometer/hydrometer.Not sure whether the particle meter part is accurate as I got nothing to measure it to.

I bought these hoping to monitor road dust, but the software is too poorly developed to be practical. It seems to be unable to properly connect with the device at times and is unable to pull the device history correctly. When it did work, the software took ~1.5 hrs to export a week’s worth of data collected at 3s intervals. The excel format of the data output is very old and Excel warns you that it make be unsafe. Save your $ and get a purpleair

Model "A1C-PM2.5+AQI+UPLOAD"When the wildfire smoke from Canada came down this summer 2023, this unit outside matched the AQI of about 150 from the AirNow dot gov site +/- 5%. The overall AQI is nice, but I really like that it includes the counts for six particle sizes on one screen. It responds to powdered drink mix, airing out my bedroom sheets and sweeping hard floors. The count of the smallest particles goes nuts--into five digits--when I fry (burn) eggs in butter. Nothing else comes close.I run an oversized HEPA filter in my room to clear allergens. When I open the door to the outside air, values rise. After I close the door, numbers drop as the filter clears the air. Sometimes I feel uncomfortable and look over to see that the AQI went over 50 (not "Good") for some reason.The humidity is significantly different from a TRIPLETT RHT313 electronic thermometer/hygrometer I have. Not sure which unit is accurate. This one has a fan drawing air towards the unit. Temperature seems reasonable.There's a screen with date and time of day that's always wrong. There's supposed to be software to set this and download data, but I haven't tracked it down. Honestly, for these fun little products, it would be best if the manufacturer just published the communications protocol because anyone could write a little script and give it away on the internet for anyone to find. Remember Hayes modems? If we could control those, we can surely communicate with this in 2023.Love it.

So I bought the 5-1 (CO2 version) and the regular HOTKREM, and was able to compare them both.First off, I like the "open" design. It allows air to move in and around freely.Unfortunately, the CO2 meter was off. Always showed lower readings, by about 75-100ppm. It's in the ballpark, but I want a bit more accuracy.The Temperature and humidity was also way off (on both devices) Strange, considering the sensor is right at the top of the unit.What really shines for both units together is the PM2.5 counter. It's quite good. I like the layout of the standard unit over the 5-1, but they both were within a few PPM of each other.I like the fact you get to see (in real time) whats in your air, from .3 microns all the way up to 10 microns.I don't bother with the Temperature of humidity readings, as they are not accurate, so I leave on the PM2.5 meter on the screen.Speaking of screen, very nice display. Easy to read.Cute little buggers, but I'd forget the 5 in1 and just get the standard one for it's cool PM2.5 meter..It does not have any battery's, so it will need to be plugged in all the time, via a common 5v USB connection.I'm giving this one a 3 stars for the excellent PM2.5 counter.

I thought I’d purchased a gimmick, the numbers on the pm counter stayed at zero unless I forced air across the sensor. Then about a month later I was seasoning an iron skillet in the oven and when I took it out and set it on the stove it smoked off a bit, the fine smoke filled the kitchen and living area of my home, it made my eyes water so I checked to see if this air monitor and the one on my home air purifier registered the smoke and to my surprise this little monitor turned out to be a working air monitor after all, it registered 42, which was about 15 ug/m3 above my air purifier but I’m pleased it actually registered the change in air quality and the numbers dropped as my air purifier captured the smoke particles - as the pictures show over time. I would give it 5 stars but it stays at zero all the time while my air purifier registers 1-2 ug/m3 on 2.5 ppm and moves up and down over the day if the window is open or I am cooking or cleaning and changing the air quality through my activities. It doesn’t have a battery and has to stay plugged in so it will not work if your power goes out but I suppose that is a minor issue compared to not having electricity :). All in all I am pleased with this product particularly for the price. I wouldn’t say any of these air quality monitors is scientifically accurate, but they do a nice job in conveying the otherwise unseen shifts in air quality.