Dyson Wrong Air Quality / Temperature: How to Fix It

Your Dyson fan suddenly shows wrong air quality reports and / or a wrong temperature?

Oftentimes, the air quality report shows a 999 value and the temperature shows 0°C (or °K).

Or the air quality report and temperature are stuck at a certain value, or they don’t show values at all.

This usually indicates a problem with the air quality and temperature sensor. Usually, the problem is easy to fix and requires just a few minutes of your time.

How to Fix Your Dyson Fan Reporting Wrong Air Quality / Temperature Data

Here’s how to fix your Dyson fan reporting nonsensical air quality and temperature.

1. Reset To Factory Settings

The first thing you should do is reset your Dyson fan to factory settings. A reset to factory settings forces the air quality and temperature sensors to recalibrate, which oftentimes solves the issue.

How to Reset your Dyson to Factory Settings

To reset your Dyson fan to factory settings, hold the power button on the device and on the remote simultaneously for 10 seconds.

Wait for the 10-second countdown animation on your Dyson fan display to disappear.

Initially, after the reset, some air quality readings may not show, because the fan needs time to calibrate again.

Let the fan run for an hour to self-calibrate.

Then, check the different air quality / temperature / humidity displays.

The values should be correct now.

If they aren’t, continue with the next section.

Why does a Reset to Factory Settings work?

The air quality and temperature sensors in your Dyson fan send electrical pulses that are converted to a meaningful air quality value and temperature. This conversion is called calibration.

And if the mathematical calibration function in your Dyson fan’s software uses wrong parameters to convert electric signals to air quality and temperature values on your Dyson’s display, it will display nonsensical values (999 air quality, 0° temperature).

After a reset, Dyson fans self-calibrate and establish new calibration parameters. This usually fixes the problem with wrong air quality and temperature readings.

2. Clean Air Quality and Temperature Sensor

If your Dyson fan still shows odd air quality and temperature readings after a factory reset, likely the air quality and temperature sensors are clogged.

When dust and grease settle on the sensors, they can’t measure air pollution and temperature properly anymore.

How to Clean Dyson Fan Sensors

To fix it clean the pollution and air quality sensors of your Dyson fan.

dyson sensor slits openings
Dyson fan air quality and temperature sensors sit inside these two openings

The sensors sit inside the two long and narrow opening slits in the side of the fan housing, above the air inlet holes.

  1. Using a vacuum cleaner: Point a vacuum cleaner at the sensor openings to remove the dust. I recommend using a narrow vacuum attachment, optionally with a brush attached. Without an attachment, the air stream is not as focused and you risk scratching your Dyson fan.
  2. Using Q-tips and rubbing alcohol: Soak a Q-tip in rubbing alcohol and clean the sensor opening with it.
    Rubbing alcohol dissolves grease.
    The Q-tip + rubbing alcohol method is preferable to a vacuum cleaner when your Dyson fan is very dirty,  since it removes residue more effectively.
  3. Blow into the sensor openings: The quickest, but least thorough method is to just blow into the sensor openings. In case of light clogging a strong blow is already enough.

After cleaning the sensors, turn on your Dyson fan. The air quality and temperature readings should work properly now.

If the values are still off, possibly your Dyson fan’s calibration is off due to the previous clogging.

In this case, do a reset to factory settings by pressing the power button on the device and on the remote control simultaneously for 10 seconds (as described in the previous section).

3. Replace Dyson Fan

If neither the reset to factory settings nor the sensor cleaning works, replace your Dyson fan.

Within Warranty: Request Refund

Dyson fans have a 2-year warranty. Within that period, Dyson will repair or replace your Dyson fan.

If you’re within the warranty period, contact Dyson support and request a replacement.

If you bought your Dyson fan from Amazon, or a similar store, you can also contact the store you bought it from and request a refund or replacement.

In most cases, you’ll get it. The newer your Dyson fan is, the better your chances are.

Outside of Warranty: Sell Broken Fan and Buy a New One

If your Dyson fan is older than 2 years I recommend selling your defective fan. There are plenty of fixing & flipping businesses looking for broken Dyson fans to repair and sell for a profit.

So, on any large online marketplace, you’ll get a competitive price.

Also, make sure to mention that your Dyson fan is working fine, only the sensor readings are off / not working.

That indicates to a professional repairman that the issue is easy to fix, resulting in more money for you.

With the money you get, buy a new Dyson fan. Usually, this approach is much more cost-effective than doing your own repair.

I recommend getting the Dyson Hot+Cool HP10 (click here to view it on amazon).


Fixing the problem with the wrong air quality and temperature report is very easy. Usually, a hard reset and / or sensor cleaning suffices.

To fix the Dyson air quality / temperature problem, reset to factory settings, holding both power buttons (on remote and fan) for 10 seconds. Then, clean the fan sensors with a vacuum or rubbing alcohol + Q-tip.

If these fixes don’t work for you, request a replacement fan, if you’re within the warranty period. Else, sell your fan as broken, and buy a new one.