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RESET® Monitors FAQ

Welcome to the FAQ section for RESET Monitors.

Please note that all content below currently is related to RESET Air Accredited Monitors only.

Click here to go back to RESET Monitors introduction page.
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1. Accreditation Process

The accreditation process for a RESET Accredited Monitor and a RESET Accredited Provider is separate because RESET Air Accredited Data Provider has its own set of requirements.

For the Monitor process, please refer to the RESET Air Accredited Monitors Process page.

For the Data Provider process, please refer to the RESET Data Providers Process page.

That is correct.

We currently do not have a test procedure for Grade A because we do not believe we have the necessary equipment required to test at that level of accuracy.

Currently, all monitor testing and accreditation is done in house in our office in Shanghai.

We use the same reference device for both indoor and in-duct. The difference is that for in-duct monitors with a pump, we place them outside of the testing box and with in-ducts that are designed for passive air collection (without a pump), we test them in the same way as an indoor monitor.

RESET can start at any time and the process typically takes around 2 months. RESET does approximately 3 weeks of testing and it takes approximately 1-2 weeks for compiling the report. The extra time is slotted in because shipping and set up typically will require more time than initially expected.

It is common for monitors being tested to not pass the first time around. There is a free 2nd test, but please take into consideration the time it takes for the 2nd test to be completed.

If a monitor does not pass the first time around, there is a free 2nd test. If a 3rd test is required, then there will be additional fees required.

2. Monitor Requirements

RESET currently does not have a process for accrediting other indicators such as PM10, ozone, or NOx, but plan to include it as optional metrics in the next iteration of the standard.

All RESET Accredited Monitors must demonstrate the ability to push data to the cloud, whether directly or via a proxy. RESET does not specify specifically what protocol should be used (i.e. RS-485, modbus, WiFi, MQTT, LORA, etc., can all be used).


Data sheets are reference to the designed parameter, but actual usage might differ. Therefore, we recommend using data sheets as reference, but the final results will be determined by the actual testing procedure found in RESET Air Accredited Monitor Process.

RESET's monitor testing focus is on intra-model variability. Please refer to RESET Air Accredited Monitor Process for the testing procedures and details of how the testing is results are calculated. You can find sample calculation spreadsheets and sample reports in the Document Downloads section of the page.

For the 2.6: RESET Air Standard for Accredited Monitors, RESET plans to update the language and requirement around accuracy to reflect intra-model variability in the next iteration of the standard.


RESET uses ambient calibration because its a better reflection of air in non-lab environments.

Note that when RESET performs monitor testing, the reference is used for the trend, making sure that the peaks and troughs of the IAQ monitors being tested adn the reference are aligned in regards to time.

The reference is not used for absolute accuracy because locations around the world will have different PM2.5 calibration, thus different results. Instead, the test is looking for intra-variability between the monitors.

That is correct. For TVOC, it is the same approach. Especially with different brand and make of sensors in the market currently, we can not expect them to work exactly the same, so the most important aspect is that the TVOC readings of the IAQ monitors being tested fulfill the intra-model variability requirements.

This is a problem in the industry right now. TVOC sensors are not consistent because different brands of TVOC sensors are designed differently and even the same brand can have different readings depending on the setup. There are a few basic tips for best practice to have the best readings:

  1. Use the same monitor since different monitors, even if they have the same sensor, might have slightly different calibration.
  2. A lot of these monitors re-zero their TVOC readings when they get turned on, so you want to start them in a very low TVOC environment. If you want to test the monitors, turn them on at the same time, right beside each other, for the best result. Different monitors have different rules around how the zeroing of TVOC works, so that is another reason why monitors tend to not read the same across brands.

The best way is to be honest and transparent with the state of TVOC sensors and offer best practice suggestions, as listed in the question above.

We recently updated the RESET Air Accredited Monitor Process page with more details on testing procedure and sample reports available for download (scroll to the bottom): https://reset.build/programs/monitors/process-air. This might help provide a better idea on what has been done.

The key thing to note is our tests can only determine that it is possible for these monitors to perform according to standard. We do not check every monitor that comes off the factory line. A good way to do a performance check is to place the monitors that have been acquired in one room, right next to each other, and turn them all on at the same time and see if the readings are close over the period of a week.

The direct answer is no. RESET will not accept a VOC index by itself, but if the VOC index can be converted to ppb or ug/m3, then it is acceptable.

Below is the logic behind this decision:

We understand the ideas behind moving towards a VOC Index. A VOC Index might better reflect the idea that TVOC readings should be used more as a reference point rather than an absolute reading on the healthiness of indoor air. With the complicated nature of TVOC, a TVOC reading in ppb or ug/m3 cannot 100% reflect whether or not the indoor air quality is healthy due to there being harmful and unharmful VOCs.

This does lead to the fact that the TVOC thresholds set by RESET is slightly arbitrary. The truth is, there can never be a definitive TVOC number that represents healthy air or unhealthy air due to the nature of TVOC being a basket of different VOCs and it cannot differentiate between harmful and unharmful VOCs.

RESET will to require IAQ monitors that output an index to also be able to provide a concentration output. This aligns with our testing methodology where for TVOC, we are not expecting monitors of different brand and makes to have the exact same reading, but monitors of the same brand and make should have very similar readings.

This decision is made due to the requirement of a threshold for RESET Projects, therefore, a concentration reading in ppb or ug/m3 is still very important to have some relative method to compare against absolute readings from spot tests. Therefore, the current requirement is that all VOC indexes will need some way to convert the index into either ppb or ug/m3.

Our Monitor Testing Process page includes more details on the testing process and sample reports: https://reset.build/programs/monitors/process-air.)

Our general approach is to move towards more transparency and also continue to provide education to the market in regards to the use cases for TVOC sensors. There are plans to require monitor device manufacturers to provide a correlation function between TVOC output (whether it is an VOC Index, ppb, or ug/m3) of the IAQ monitor and the gas which has been used for calibrating the TVOC sensor, valid under controlled laboratory conditions, to have more data around calibration metadata and how results are obtained.

At the moment, there is no industry standard defining exactly how a TVOC sensor has to be calibrated, therefore, the outputs of sensors and monitors from different manufacturers may vary significantly from each other.

3. Calibration Requirements

Although recommended, please note that annual calibration is currently not enforced by RESET.

We do not currently have a sample calibration report available at this time. This is a part of the accreditation that we have not yet fully enforced, but we are looking at ways to include it officially.

This question is in reference to the ability of monitors to be accompanied with documentation from the original manufacturer attesting that the monitor was appropriately calibrated and confirmed functional without defect prior to shipping.

According to the RESET Air Standard for Accredited Monitors v2.0 section 2.6.2.g, it is stated that each monitor must ship with a calibration report.

This was the original intention but was never enforced, so it became optional. Although not enforced, it is completely in a user's right to ask whether or not the monitors they are purchasing have been calibrated after the sensor components have been installed. Since RESET does not have an official format for the report, it is currently down to the individual monitor manufacturers on how they want to showcase this if asked.

As a side note, a recommendation is to also do a Performance Check, where you place multiple monitors of the same brand and make next to each other and see if they perform consistently against each other. This is a good way to confirm that the units are going to have very similar readings, and this is also how RESET does initial testing for accreditation purposes. It is also a good way to see if monitors are still performing properly after a period of time.

Yes, both options will be considered satisfactory.

In the RESET Air Standard for Accredited Monitors, it is mentioned that monitors “must demonstrate the ability to be re-calibrated or be removed and exchange for a new or newly calibrated sensor”, but it does not state specific details in regards to the method of recalibration.

Currently, there are two concepts around calibration: software and hardware. Software calibration consists of re-adjusting the readings and address drift based on an assumed initial reference value. Hardware calibration requires the refurbishment or replacement of individual sensor modules as part of their annual re-calibration.

Ideally, there is some method of physical re-calibration or exchange of the sensors, but due to market limitations (access and cost), we also accept software calibration, which is significantly more cost-effective as it can also be done remotely.

ABC is a form of calibration, but cannot be used as a replacement for an official Annual Calibration.

ABC is a form of calibration, but cannot be used as a replacement for an official Annual Calibration.

ABC for TVOC tends to create other issues as well. TVOC sensors are not as accurate as CO2 sensors, and with different algorithms for ABC, which auto-zeroes the TVOC sensor, it can vastly affect the readings over time. One of the reasons that TVOC readings are so different between different monitors can simply be attributed to the monitors being turned on at different times and the ABC taking effect in different ways.

Typically, TVOC sensors are zeroed when they the IAQ monitor is powered on and different sensor manufacturers have different auto-zeroing rules (i.e. once every 24 hours, which might skew results if TVOC levels maintain high readings for 24+ hours).

4. Data Requirements

We do not track how much data is lost within the 30 minutes. This is built-in leeway. We are only tracking how many of the 30 minute averages get lost.