Rheem Furnace Filter Replacement Made Easy (No Tools Required)

Rheem

Summary

  • Replacing a Rheem furnace filter can be done DIY in under five minutes without any tools.
  • Filters are typically located below the blower compartment or in a side-return duct slot.
  • Signs that a filter needs to be changed include dust accumulation, airflow noise, and increased indoor allergies.
  • Choose the right filter size and type, with pleated filters being more effective than fiberglass screens.
  • To extend filter life, vacuum vents monthly, brush pets regularly, and seal windows and doors during heating season.

Breathe Easier—Without Calling an HVAC Pro

Replacing your furnace filter might seem like a “technician-only” task. But if you own a Rheem system, here’s the good news: you can do it yourself, without any tools, in under five minutes.

Seriously.

Whether you have a Rheem Classic, Classic Plus, or Prestige model, this guide will show you exactly where to find your filter, how to change it, and what to look out for—so you can keep your air clean and your furnace happy.

Rheem furnace filter replacement guide

Step 1: Know Where Your Filter Lives

Most Rheem furnace filters are tucked into one of two places:

  • Below the blower compartment (accessed by removing the lower panel)

  • Or in a side-return duct slot (a slide-in tray on the side of the furnace)

To check:

  1. Turn your furnace off at the thermostat or power switch.

  2. Open the lower panel or inspect the ductwork on either side.

  3. Look for a rectangular slot where the filter slides in and out.

If you see a white (or grayish) pleated panel—bingo.

Step 2: Is It Time to Change the Filter?

Don’t wait for a technician to tell you. Look for these signs:

  • The filter looks dusty, dark, or fuzzy

  • You hear faint whistling or airflow noise at the return vents

  • Your house feels dustier than usual

  • You’ve noticed more sneezing or allergies indoors

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For most homes, change the filter every 2–3 months. If you have pets or use your furnace daily in winter, go monthly.

Step 3: Find the Right Filter Size & Type

Before you pull the old one out completely, check the frame for its size label—it’ll look something like 16x25x1 or 20x20x1.

Standard sizes for Rheem units include:

  • 16x25x1

  • 20x25x1

  • 16x20x1

  • 20x20x1

Filter types:

  • MERV 8: Great for general dust and lint

  • MERV 11: Better for homes with pets or allergies

  • MERV 13: High-end filtration—traps smoke, mold, and tiny particles

Stick with pleated filters. They’re more effective than those cheap fiberglass screens.

Step 4: Replace It the Right Way

Here’s the process:

  1. Turn the furnace off.

  2. Slide out the old filter.

  3. Check the airflow arrow on the old filter—it should point toward the furnace.

  4. Grab a matching new filter and insert it with the arrow pointing the same way.

  5. Turn the system back on and enjoy quieter, cleaner air.

No screws. No screwdrivers. No stress.

Bonus Tips to Help Your Filter Last Longer

  • Vacuum return air vents every month

  • Brush pets regularly to reduce shedding

  • Keep windows and doors sealed during heating season

  • Clean ducts every few years to reduce long-term buildup

Cleaner air in = cleaner filter out = less work for your furnace.

Simple Filter Reminder Chart

What to Do How Often
Check filter for dust Monthly
Replace filter Every 60–90 days
Vacuum vents Monthly
Full system inspection Annually

 

Want to make life easier? Set a recurring alert on your phone for the first of each month.

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More on Rheem– Here

 

Kelsey Neff
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