How to use your Wave Mini as a mould risk indicator

Place your Wave Mini
Place your Wave Mini (tips on placement below)
Read your graphs and data
Read your graphs
and data
Make positive changes to prevent mold
Make positive changes to prevent mould


For the most accurate readings, the device should be placed where mould is most likely to grow. The most vulnerable areas are often the coldest and least ventilated.

Next to a wall or on a windowsill


Next to a wall or on a windowsill

Underneath or behind furniture


Underneath or behind furniture

Towards the floor on external walls


Towards the floor on external walls

Next to underground external walls


Next to underground external walls

Small enclosures (such as behind an access door or wall)


Small enclosures (such as behind an access door or wall)

Common rooms with mould risk:

  • Rooms with cold external walls and/or poor insulation
  • Rooms with poor ventilation
  • Basement
  • Attic
  • Bathroom
  • Garages
  • Shed
  • Crawl space

Other assets with mould risk:

  • Campervans
  • Recreational vehicles
  • Boats
  • Second homes/cabins

Understanding your wave mini graphs and data

What do my mould risk levels mean?


Good. Little risk for mould growth, but there is always a possibility for mould above 0.


Fair. Mould will grow especially on vulnerable materials such as textiles and wood.


Poor. There is a high mould risk for all kinds of materials.

Mould risk graphs

It will take about 2 days for the mould risk indicator to give you an indication of your mould risk. “Processing data” will display when ready or when it is syncing using Bluetooth.

The mould algorithm depends significantly on time, which means that long term monitoring of your mould risk is essential.

When your graph is growing steadily, the risk of mould is increasing. You should take action before it gets worse.

When your graph turns green after some time in yellow or red: mould will start to die, however, the process is slow. Make sure to remove visible mould.

This is a very typical reading. If your humidity is always less than 80% in the most humid location in your room, you likely have no risk of mould. If you think there is a high likelihood of mould, move the device closer to the suspected mould risk area.


Understanding the limitations of the mould risk indicator

Mould prevention

The mould risk indicator will not detect actual mould spores in the air. However, it will tell you when the conditions in a space are at risk for mould growth. This means it is a great device to use to prevent mould or to proactively watch out for the chance of mould. However, once mould has started growing and is visible, it should always be removed. This can be easily done on your own. If you are unsure if what you are seeing is mould, then use a mould test kit or contact a mould professional.


How does the Airthings mould risk indicator work?

The mould risk sensor uses an algorithm based on the temperature and humidity sensor to measure how fast mould can grow under the current conditions. Since the material where mould is growing is an important condition to the speed of mould growth, we have assumed the more vulnerable materials in our equation: wood and textiles. Therefore, if your device is showing yellow in an all tile bathroom, there is less chance of mould growth.

Our scale

We have used the criteria for moisture control in buildings based on ASHRAE standards (a global society advancing human well-being through sustainable technology for all buildings). Their mould index scale is from 0 (no mould) to 6 (full mould growth population) and it takes into account material types to describe the total accumulated mould after a certain time. We base our indicator on the rate change of the mould index: 0 means declining index, while 10 means maximum increase to the index.

GOOD: 0-3

FAIR: 3-5

POOR: 5-10

What it does not do

  • It does not detect mould spores in the air.
  • It does not detect mould risk due to high humidity inside constructions (leaks in roof, flooding, within walls, or incorrect construction).
  • It does not estimate mould risk in areas away from the device (therefore the middle of the room is not a proper placement).

Wave Mini: Your indoor air quality companion

Mould growth at home affects the air we breathe triggering asthma, allergies, and illness. Stay ahead of mould growth with Wave Mini, because once you see it, it's too late!

Buy Wave Mini