Maintenance procedure · Written to ASD-STE100 Issue 9 · Formatted to ANSI Z535

Change the Filter — Dyson Purifier Cool

Replace the HEPA and carbon filters on a Dyson Purifier Cool air purifier, and reset the filter life
ApplicabilityDyson Purifier Cool air purifier fans covered by the Dyson Purifier Cool user manual published on dyson.com (document 369968-01, filed under the TP09 product path). The manual covers three filter configurations under the Purifier Cool name, including the Purifier Cool Formaldehyde with its permanent catalytic filter, and does not print a model number in its text. Check which filters your own machine holds before you order a replacement, and check your own manual if your machine is a different Dyson model.
Task time10 min to 14 min editorial estimate, not a measurement
PersonnelOne
Revisionv1 · 2026-07-29
BEFORE YOU BEGIN

Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.

Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.

Summary

Changing the filter on a Dyson Purifier Cool is about ten minutes of work, and the step people skip is the last one: resetting the filter life. Miss it and the machine keeps counting down from where the old filter left off, so the screen tells you the new filter is nearly spent. The other thing worth knowing before you order anything is that this machine ships in three filter configurations — one combined HEPA+Carbon filter, a separate HEPA and a separate carbon filter, or a HEPA+Carbon filter alongside a permanent catalytic filter on the Formaldehyde model — and the reset is done with a different button depending on which you have.

Every step carries a page link into Dyson's own user manual, so you can check any instruction against the manufacturer's document in one click. Nothing on this page is copied from that manual. One thing the manual does not give is how long a filter lasts in hours or months, so this page does not print a figure either; the machine tracks it and tells you.

Necessary equipment

ItemNote
Lint-free clothMake the cloth damp. Do not make the cloth wet.
Soft brushUse the brush to remove dust from the air inlet holes.
Replacement filter materialGet the filter type that your machine holds.

Identify the filters of your machine

Estimated 3 min to 7 min

NOTEThree filter configurations use this manual. The correct filter and the correct reset button are different for each one.
How long a filter lasts
Unverified — do not rely on this value
READ THE REMAINING FILTER LIFE FROM THE SCREEN OF THE MACHINE

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Replacement filter for your machine
Unverified — do not rely on this value
IDENTIFY THE FILTER TYPE FROM THE FILTER IN THE MACHINE

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

  1. Push the Information button on the remote control.
    • You can also see this data in the Dyson Link app.
    <1m
  2. Read the filter life from the screen.
    • A filter symbol on the screen gives the life of the filter.
    • The machine tells you when the filter needs a replacement.
    <1m
  3. Identify the filters that your machine holds.
    • One configuration has a HEPA+Carbon filter.
    • One configuration has a separate HEPA filter and a separate carbon filter.
    • The Formaldehyde configuration also has a permanent catalytic filter.
    1m
  4. Get a replacement filter of the same type.
    • Do not get a replacement for the catalytic filter. The catalytic filter is permanent.
    1m

Prepare the machine

Estimated under a minute

CAUTION

DISCONNECT THE MACHINE FROM THE POWER SUPPLY BEFORE YOU OPEN THE OUTER COVERS.
The machine can start while your hands are in the filter cover.

  1. Set the machine to off.
    • Push the Standby button on the machine or on the remote control.
    <1m
  2. Disconnect the machine from the power supply.
    <1m
  3. Put the machine on a clear flat surface.
    • Hold the machine by its base.
    • Do not hold the machine by the loop amplifier.
    <1m

Remove the used filter

Estimated 2 min

  1. Push the button on each side of the machine.
    • This releases the outer covers.
    <1m
  2. Remove the two outer covers from the machine.
    <1m
  3. Push the tabs on the used filter.
    • The tabs hold the filter in the outer cover.
    <1m
  4. Remove the used filter from the outer cover.
    <1m
  5. If your machine has a carbon filter on the base, remove that filter.
    <1m

Install the new filter

Estimated 2 min

NOTICE

USE ONLY A FILTER THAT IS CORRECT FOR YOUR MACHINE.
A filter of the wrong type does not seal in the outer cover.

  1. Push the new filter into the outer cover.
    • Make sure that the tabs engage.
    <1m
  2. If your machine has a carbon filter on the base, install the new carbon filter.
    <1m
  3. Put the two outer covers into position on the base.
    <1m
  4. Push each cover until it clicks into position.
    • Both covers must click.
    <1m
  5. Connect the machine to the power supply.
    <1m
  6. Set the machine to on.
    <1m

Reset the filter life

Estimated under a minute

NOTEDo not omit this section. The machine counts the life of the old filter until you reset it.
Filter life reset button hold time
Manufacturer or standard verified
5 seconds

Source: Dyson Purifier Cool air purifier — user manual · tier 1 · accessed 2026-07-29

NOTICE

RESET THE FILTER LIFE AFTER YOU INSTALL THE NEW FILTER.
The machine shows the life of the old filter until you do this.

  1. Reset the filter life with the Night mode button.
    • Hold the button. Do not release it until the countdown ends.
    • This button resets a HEPA+Carbon filter and a HEPA filter.
    <1m
  2. Look at the countdown on the display of the machine.
    • The display counts down from five.
    • The machine is then ready for use.
    <1m
  3. If your machine has a carbon filter on the base, hold the Oscillation button.
    • Hold the button. Do not release it until the countdown ends.
    • This resets the life of the carbon filter.
    <1m

Clean the machine

Estimated 3 min

NOTICE

DO NOT USE DETERGENTS OR POLISHES ON THE MACHINE.
Dyson gives this instruction in the user manual.

  1. Clean the machine with a damp lint-free cloth.
    1m
  2. Examine the air inlet holes for blockages.
    • The air inlet holes are in the filter area.
    <1m
  3. Use a soft brush to remove the dust and the loose material.
    <1m
  4. Examine the small aperture in the loop amplifier for a blockage.
    <1m

Terminology

This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.

HEPA+Carbon filter
Also called: combined filter, hepa filter, carbon filter, dyson filter, purifier filter, air filter
outer cover
Also called: filter cover, filter housing, the shell, side covers, mesh cover
loop amplifier
Also called: the loop, the ring, the hoop, bladeless fan ring
filter life
Also called: filter light, filter warning, change filter message, filter countdown, filter percentage
catalytic filter
Also called: formaldehyde filter, permanent filter, selective catalytic oxidation filter

When to use a professional

Do not disassemble the machine. Do not remove the loop amplifier. The machine has no parts that a user can repair.

Do not wash a HEPA filter or a carbon filter. These filters are not washable. Install a new filter.

If the machine shows an error code, set the machine to off. Then set the machine to on again. Speak to Dyson Customer Care if the error code stays on the display.

Speak to Dyson Customer Care if a cover does not click into position. Air can flow around the filter if a cover is not fully closed.

Common questions

How often should I change the filter on a Dyson Purifier Cool?

The user manual does not print an interval in hours or months, and this page will not invent one. What Dyson does is track it on the machine: the remaining filter life shows on the LCD screen and in the Dyson Link app, and the machine tells you when a replacement is due. Press the Information button on the remote to see where you are. If you want a figure to plan a purchase around, ask Dyson or check the product page for your exact model rather than trusting a number from a third-party site.

Why does my Dyson still say the filter needs changing after I changed it?

Almost always because the filter life was not reset. Dyson is clear that resetting is a separate action after fitting the new filter, and the machine has no way of knowing you swapped it otherwise. Hold the Night mode button on the remote until the display counts down from five. If your machine has a separate carbon filter, that one has its own reset on the Oscillation button, so a machine with two filters needs two resets.

Can I wash the Dyson purifier filter instead of replacing it?

No. Dyson describes these as non-washable filters and the manual's instruction is to change them, not to clean them. That is different from some Dyson vacuum filters, which are washable, and the two get confused constantly. What you can clean is the machine itself: a damp lint-free cloth on the body, and a soft brush on the air inlet holes and the small aperture inside the loop.

How do I know which filter my Purifier Cool takes?

Open the covers and look. The manual covers three arrangements under the same name: a single combined HEPA+Carbon filter, a separate HEPA filter in the cover plus a carbon filter on the base, and the Formaldehyde version which adds a permanent catalytic filter you never replace. The one you have decides both which part you order and which button resets the life.

Do I need to change the catalytic filter on the Formaldehyde model?

No. Dyson states that the catalytic filter is permanent and does not need changing. Only the HEPA+Carbon filter is a consumable on that model. If a shop offers you a replacement catalytic filter for a Purifier Cool Formaldehyde, that is a reason to check what you are actually buying.

The machine is showing an error code. What should I do?

Dyson's own first move is to switch the machine off and on again. If the code comes back, the manual sends you to Dyson Customer Care rather than to any user-serviceable fix, and this page does the same. There is nothing inside the machine a reader is meant to open beyond the filter covers.

Sources

Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.

  1. Tier 1Dyson Purifier Cool air purifier — user manualDyson · accessed 2026-07-29 · re-verification due 2027-01-25

Revision history

Current version 1 · updated 2026-07-29 · next review due 2027-07-29

  1. v1 · 2026-07-29First draft. Built from the Dyson Purifier Cool user manual fetched by scripts/manuals.py, with per-step deep links into Dyson's own PDF.

Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.

Comments and corrections

Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.

Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.

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