Review: uHoo AQI Monitor

Finally is here. After having an adventure with the postal service for +40 days the uHoo device found its way to my home. I want to thank uHoo for its persistence.

Let me start by saying that this is a very promising device because it features 9 separate Sensors for Air Quality monitoring and there isn’t any other device with so many sensors for indoor use. The company was founded in August 2014 and it took them two and a half years to develop uHoo.


  • RGB LED Light
  • Temperature Sensor -40°C to 85°C / 40°F to 185°F
  • Humidity Sensor RT 0-100%
  • Air Pressure Sensor 300-1,100mbar
  • Carbon Dioxide CO2 Sensor 400-10,000ppm
  • Carbon Monoxide CO Sensor 0-1000ppm
  • VOC Sensor 0-1,000ppb
  • PM2.5 Sensor 0-200ug/m³
  • Ozone O3 Sensor 0-1,000ppb
  • *Nitrogen Dioxide NO2 Sensor 0-1000ppb
  • Micro USB Power Input 5V DC
  • WiFi 802.11 b/g/n @ 2.4 GHz

UHOO Front Back


The device is compact and it wont take a lot of space from your work surface or any other place. The design permits the air to flow from the bottom to the top without any fan inside and also it inhibits dust to fall into it. For me, it looks like a Modern Asian Skyscraper.


I haven’t opened the device, so I don’t know for sure, but from an 3D illustration they have on their website, a video on youtube and my experience I can see that they use the following sensors.

It seems that they use the MH-Z19 for CO2 measurements but they don’t because their sensor has better ranges. I don’t know which sensor is, but from my experience the sensor is super sensitive, so I recommend you not to place it in front of you for example next to the PC monitor because each time you breathe out the device will pick up the CO2 fluctuations. The software plays an important role on how the data are analyzed and interpreted. For example, when the device is turned on for the first time, it will need 48 hours to calibrate, so ignore the first readings. The CO2 sensor will read the values and the values will go through a statistical analysis to address any changes in sensor reading that is attributable to sensor drift. This is cool, isn’t it?

The Shinyei PPD42NS sensor is used to measure the Particulate Matter PM. You can read the following study with some additional info for this sensor link.

The Bosh BME280 sensor is used to measure the temperature, humidity and air pressure. Very good sensor with great accuracy and modern design. Read more here.

Finally, I can distinguish a SGX SensorTech sensor but I don’t know which one is because some SGX sensors look the same.



The iOS/Android app for the device features four main tabs on the bottom of the screen Home / Health Notes / Notifications / Settings.

  • On the Home tab you can access your device or devices and all the sensors by clicking on the name of your uHoo device. A clean UI with bold information. They use colour coding for all the stats. Green for Good, Orange for Medium and Red for High.
  • On the second tab *Health Notes the user can register all the health events like Asthma, Bronchitis, Emphysema and other illnesses and symptoms. This feature is especial useful for the individuals with chronic disorders and a great help for your MD. Your data are safe thanks to the 256-bit encryption.
  • On the third tab you can read all the notifications. They are ordered chronological. They also provide useful tips for example “Humidity environment can enhance mold growth” when humidity is above 50% for a long period of time or “Check if there is any unsealed household cleaners…” when VOCs have exceeded 250ppb for a period of time.
  • Finally on the last tab you can find the General Settings.


For me, it is very important the histogram. I want to have access to past readings from all the sensors and average values. The uHoo app provides all this information as you can see below. Once you are on the main tab you can see the histogram by turning your phone on landscape mode. The histogram is adjustable to Hourly, Daily and Monthly. You can also choose a specific time or date to read. A great addiction is the average value for each sensor for the day or hour. When you choose the monthly histogram then you get the minimum and maximum values, handy!

histogram thresholds uhoo

Each user has different thresholds on temperature, humidity, etc. As a result they provide the necessary tools to customize those thresholds on each sensor, look the image above. This way you won’t get unnecessary notifications but only the notifications that are really important to you.


uHoo costs US$299 which is a rather high price comparing with the rest of the indoor AQI monitors, but you have to think that it is the only one with so many sensors. The app constantly receives updates which indicates great support and future, no one wants a obsolete device. I would like to mention here that the software development isn’t cheap and we have to appreciate the fact that they offer us the app for free. Here, I would like to recommend some changes on the app regarding the landscape mode because in general I have that mode locked and second I would prefer if the stats tab was directly available on the main tab without the need to click on my uHoo device. Finally, I believe they have done a great work and the device offers some unique solutions to those with higher concerns on air pollution.

* The NO2 sensor and Health Notes tab will become available with an app update this fall.


12 thoughts on “Review: uHoo AQI Monitor

  1. This is not really a review. A review would be your testing the product and letting us know what you think about how it works for monitoring the air quality in your living space.

    Liked by 2 people

  2. Can you comment on how this device holds up to the competition in 2019? I am looking for an air quality sensor that can specifically measure ozone – is this device still my best choice or are there others I should consider?

    Liked by 1 person

      • Two reasons: 1. I have a whole house air filter running (Lennox PureAir) which has a UV light in it. According to Lennox, it’s ozone free, but I want to be sure. 2. We live in a very sunny environment (California) and are in a rather polluted area, next to two major highways. I’m concerned that between these two, we are at risk of ozone. Finally, more of a hunch than a reason, our cat seems to be the one who starts sneezing first when the air gets bad, so I am thinking that whatever it is, it’s close to the ground. Hence I am suspecting ozone.

        Liked by 1 person

      • I understand. Unfortunately, there are limited options for O3 monitors. Within 2-3 months I am going to review a device which has an O3 sensor too (waiting for production to complete).


  3. I too am interested in ozone concentrations. First this a serious pollutant that can damages lungs.

    In the error of COVID we don’t want to damage our lungs
    “Exposure to Ozone Modulates Human Airway Protease/Antiprotease Balance Contributing to Increased Influenza A Infection”
    Check ncbi search for PMC3322171 to find the paper.

    Also, I purchased an ozone generator to help sterilize equipment. These generators work as advertised and definitely generate enough ozone to kill viruses and bacteria and probably fungi (those are much tougher to kill). However, the ozone created are very dangerous for humans and needs to be used with caution.
    It’s like a skill saw, but you can’t tell if blade is spinning or not unless you have an $800 detector.

    If this device works as advertised it’s a great buy… however how do we trust the measurements? Reviewers rarely have thousands of dollars of scientific instruments needed to test the accuracy of the devices. Do we just trust the manufacture to be honest?


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