Change Your Aprilaire Filter in About 15 Minutes

Changing an Aprilaire humidifier filter takes roughly 15 minutes and requires no tools beyond what you have at home. Turn off the humidifier at the power switch, slide out the old filter, rinse the water panel if your model has one, insert the new filter, and turn the unit back on. The filter itself costs between $30 and $50 depending on your model number.

Most Aprilaire owners need to change the filter once a year, though homes with hard water or low humidity may need it more often. A clogged filter reduces moisture output and forces the humidifier to work harder, shortening its lifespan. Knowing your model number before you buy a replacement saves a trip back to the store.

Key Takeaways

  • Turn off the humidifier at the wall switch before opening the unit to avoid water spillage and electrical hazard.
  • Your model number is printed on a label inside the humidifier cabinet or on the back of the unit, and you need it to order the correct replacement filter.
  • The water panel (a foam or paper insert) can be rinsed under tap water and reused, but the filter itself must be replaced when it turns brown or gray.
  • Hard water buildup on the filter is normal and does not mean the filter is defective — mineral deposits are why annual replacement matters.
  • New filters cost $30 to $50 and are sold at hardware stores, online retailers, and directly from Aprilaire's website.

Locate Your Model Number Before You Start

Find your Aprilaire model number on a white label inside the humidifier cabinet or on the back panel of the unit. Write it down or take a photo. Common residential models are the 400, 500, 600, 700, and 8100, but dozens of variations exist. The model number determines which filter you need — buying the wrong one means a wasted trip.

If you cannot find a label, check your original paperwork or the manual. If you have neither, call Aprilaire's customer service line with your humidifier's serial number and they will tell you the model. You can also search your model number online to confirm the correct filter part number before you buy.

Turn Off Power and Locate the Filter Compartment

Switch off the humidifier at the wall outlet or at the power switch on the unit itself. Wait a few minutes for any residual moisture to settle. Open the humidifier cabinet or access panel — most Aprilaire models have a hinged door on the front or side that swings open without tools.

Inside, you will see the filter mounted vertically or horizontally depending on your model. It looks like a thick, accordion-folded pad, usually white or tan when new. The water panel (a thinner foam or paper sheet) sits in front of or behind the filter. Take a moment to note how both pieces sit so you can reinstall them correctly.

Remove the Old Filter and Rinse the Water Panel

Slide or lift the old filter straight out of its slot. It will likely be brown, gray, or discolored from mineral deposits and dust — this is normal. Set it aside for disposal. Do not try to clean or reuse the filter itself; it cannot be restored to working condition.

If your model has a water panel in front of the filter, remove it next. Rinse it under cool tap water to remove dust and mineral buildup. You can gently brush it with a soft brush if deposits are heavy, but do not scrub hard or wring it out. The water panel can be reused for several years if it is not torn or falling apart. If it crumbles or has holes, replace it along with the filter.

Insert the New Filter and Reassemble

Slide the new filter into the same slot where the old one sat, making sure it sits flat and fully inserted. The filter should not be forced; it should slide in smoothly. Check that the edges are flush with the frame and no part of the filter is bent or sticking out.

Reinstall the water panel in front of the filter if your model has one. Make sure it is seated properly and not blocking the filter. Close the humidifier cabinet or access panel and find it if it has a latch or clip. Do not force the door shut; if it does not close smoothly, the filter or water panel is not seated correctly.

Turn the Humidifier Back On and Check for Leaks

Switch the humidifier back on at the power outlet or wall switch. Let it run for 5 to 10 minutes and watch for water leaks around the cabinet seams or the access panel. A small amount of condensation on the outside is normal, but steady dripping means something is not seated correctly.

If you see a leak, turn the unit off when ready, open the cabinet, and check that the filter and water panel are fully inserted and not tilted. Reposition them and try again. If leaking continues, the gasket or seal inside the cabinet may be worn and may need replacement — contact Aprilaire support for guidance.

When to Replace Your Filter

Most Aprilaire filters last 12 months of regular use. In homes with hard water, mineral deposits build up faster and you may need to replace the filter every 6 to 9 months. In dry climates where the humidifier runs constantly, yearly replacement is standard.

Signs that a filter needs replacement include reduced moisture output, white dust around the humidifier, or a filter that is visibly brown or clogged. A clogged filter forces the humidifier motor to work harder and can cause the unit to shut down prematurely. Replacing the filter on schedule keeps the humidifier running efficiently and extends its life.

Frequently Asked Questions

Can I clean and reuse my Aprilaire filter instead of replacing it?

No. The filter is designed to be replaced, not cleaned. Washing it damages the material and does not restore its ability to trap minerals and dust. The water panel can be rinsed and reused, but the filter itself must be new. Reusing a clogged filter reduces moisture output and strains the humidifier motor.

What is the difference between the filter and the water panel?

The water panel is a thin foam or paper sheet that sits in front of the filter and helps distribute water evenly. The filter is the thicker accordion-folded pad behind it that traps minerals and dust. The water panel can be rinsed and reused for years; the filter must be replaced annually.

Where do I buy Aprilaire replacement filters?

Aprilaire filters are sold at hardware stores like Home Depot and Lowe's, online at Amazon and Walmart, and directly from Aprilaire's website. Prices range from $30 to $50 depending on the model. Buying from the manufacturer's website guarantees you have the correct part number for your specific model.

What happens if I use the wrong filter size?

A filter that is too small will not seal properly and water will bypass it, reducing humidifier performance. A filter that is too large will not fit in the slot. Always confirm your model number before ordering to avoid wasting money on the wrong part.

Do I need to replace the water panel every time I change the filter?

No. Rinse the water panel under tap water and reuse it unless it is torn, crumbling, or falling apart. Most water panels last several years. Replace it only when it shows visible damage or no longer holds its shape after rinsing.