Quick Tip: How to Replace Your W-Cat Pre-Filter in 3 Easy Steps

Hey cat parents! If you own a W-Cat Air Purifier (WS360A), you already know how much fur it pulls out of the air. That thick layer of cat hair on the pre-filter? That's proof it's working hard for you.

But here's the thing — your W-Cat can only do its job if the pre-filter stays fresh. A clogged pre-filter restricts airflow, makes the fan work harder, and lets more dander slip through to your HEPA filter, shortening its lifespan.

The good news: replacing the pre-filter takes under a minute. The W-Cat uses disposable electrostatic cotton sheets that come in a convenient 10-pack — no washing, no drying time, no fuss. Here's exactly how to swap one out.

What Is the Pre-Filter and Why Does It Matter?

The pre-filter is the outermost filter layer in your W-Cat — the first line of defense. It catches large particles like cat hair, dust bunnies, and bigger bits of dander before they reach the composite filter (HEPA + activated carbon) inside.

Think of it as a screen door for your air purifier. When it's fresh, air flows freely and the composite filter only deals with the fine stuff. When it's matted with fur, everything slows down — reduced airflow, higher energy use, and faster composite filter wear.

The W-Cat's pre-filter uses electrostatic cotton — a disposable, tear‑off sheet material that traps particles with a static charge. When it gets dirty, you simply peel it off and apply a new one. No rinsing, no drying, no downtime.

Step 1: Check If It's Time to Replace

How do you know when the electrostatic cotton sheet needs replacing? Here's the easy way:

• Visual check: If you can see a visible layer of hair, dust, or debris covering the sheet, it's time for a fresh one.

• During spring and fall shedding season, your cat drops fur at a much higher rate — so you may need to replace the sheet more frequently. Get in the habit of doing a quick visual check every couple of weeks during peak shedding.

💡 Pro tip: Do this near a trash can. There will be loose hair on the used sheet, and you'll want to dispose of it quickly.

Step 2: Peel Off the Used Electrostatic Cotton Sheet

1. Turn off your W‑Cat and unplug the power cord.

2. Press the PUSH grooves on both sides of the machine with both hands, then lift the upper part upwards to open the filter compartment.

3. Inside, you'll see the electrostatic cotton sheet wrapped around the cylindrical composite filter (HEPA + carbon).

4. Simply peel the used sheet off. If it's been a while since your last replacement, expect a thick layer of trapped fur and dust — that's a good sign. It means the sheet was doing its job, protecting your composite filter from all that debris.

5. Toss the used sheet in the trash. That's it — no rinsing, no drying, no waiting.

Step 3: Apply a Fresh Sheet From the 10‑Pack

1. Take a new electrostatic cotton sheet from your pack.

2. Important: The sheet comes in a protective PE bag. Remove the bag completely before wrapping — otherwise the purifier cannot draw air.

3. Wrap the fresh electrostatic cotton sheet around the composite filter, just like the old one was positioned. Make sure it sits snugly with no gaps or loose edges — you want full coverage so large particles can't bypass the pre-filter layer.

4. Close the filter compartment: lower the upper part until you hear a click.

5. Plug in your W‑Cat and turn it on. That's it — the whole process takes under 60 seconds.

A Note About the Composite Filter

Replacing the electrostatic cotton sheet does not require replacing the composite filter underneath. The composite filter (HEPA + carbon) lasts about 3000 hours (roughly 4 months) and has its own indicator light:

• Lock icon flashes red + AQI ring breathes green at 1Hz → 2800 hours, prepare to replace soon

• Lock icon flashes red + AQI ring breathes green at 2Hz → 3000 hours, replace immediately

After replacing the composite filter, remember to press and hold the Child Lock button for 10 seconds to reset the timer. Replacing only the electrostatic cotton requires no reset.

How Often Should You Replace the Pre-Filter Sheet?

Under normal conditions, one sheet lasts several weeks for most single‑cat households. During spring and fall shedding season, your cat drops fur at a much higher rate — and the sheet fills up faster.

• During peak shedding: check your pre-filter sheet weekly and replace as needed.

This one small habit makes a real difference. It keeps airflow strong, protects your composite filter from premature clogging, and ensures your W‑Cat is capturing dander and odors at full capacity when it matters most.

For a deeper look at shedding-season filter schedules, check out our guide: Spring Shedding Season: How Often Should You Replace Your Air Purifier Pre-Filter?

Quick Recap

That's it — under a minute of effort to keep your W-Cat running at its best. Each pack comes with 10 sheets, so you're covered for months. For more tips on getting the most out of your purifier, including how to extend your HEPA filter's lifespan, read our complete guide to maximizing your W-Cat air purifier.

Photos by Alpha En, ThisIsEngineering, and Bianca Vogt on Pexels