As an Amazon Associate I earn from qualifying purchases.Updated: March 27, 2026
The Furnace Filter in your Rheem RA18 furnace is crucial for clean air circulation. It traps dust, dirt, and other airborne particles that can damage the internal components and reduce heating efficiency. Over time, the filter becomes clogged and needs replacement to ensure your furnace runs smoothly and safely. Neglecting filter replacements can lead to decreased performance, increased energy consumption, and potential damage to the unit.
$36.70
Price from Amazon • As an Amazon Associate I earn from qualifying purchases.
Function: The Furnace Filter removes dust, dirt, pollen, and other airborne particles from the air circulating through your furnace.
Signs it needs replacing: Reduced airflow, visible buildup of dirt on the filter, unusual noises from the furnace, increased energy bills.
OEM vs aftermarket: OEM filters (Rheem brand) are designed specifically for your RA18 model but may cost more. Aftermarket filters are often cheaper and can be just as effective if they're compatible with your model number.
Installation: Replacing the Furnace Filter is generally straightforward. Turn off the furnace, locate the filter compartment, remove the old filter, and insert the new one in the correct direction. Consult your owner's manual for specific instructions.
Replacement schedule: every 1 month
Compatibility warning: Always verify part number matches your exact model before ordering
Pros & Cons
Pros
✓ Restores device to original performance without buying a new unit
✓ Significantly cheaper than a full device replacement
✓ Multiple options available from OEM and aftermarket sellers
Cons
✗ OEM parts cost more than third-party alternatives
✗ Wrong part number will not fit — model verification is essential
Common Use Cases
Scheduled maintenance on the every 1 month replacement cycle
Performance restoration after noticing reduced output or efficiency
Preventive replacement before a worn part causes secondary damage
Who Should Buy This
This Furnace Filter replacement is for Rheem RA18 owners experiencing reduced heating efficiency or airflow, wanting to extend their furnace's lifespan.
Not ideal for: If your furnace is severely damaged or beyond repair, a full device replacement may be more cost-effective than simply replacing the filter.
Good to Know Before Buying
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Always confirm your exact model number (RA18036) before ordering. Part numbers vary between model variants and production years. Check the label on your device or original documentation to be sure.
Frequently Asked Questions
What is the part number for the Rheem RA18 Furnace Filter?
The part number is RHEEM-1500M. Always verify this matches your exact model (RA18036) before ordering, as similar models may use different parts.
How often should I replace the Furnace Filter on my Rheem RA18?
every 1 month
Will aftermarket Furnace Filter replacements work in my Rheem RA18?
Third-party parts are widely available and often cheaper than OEM. Look for listings that specifically mention compatibility with model RA18036 and check buyer reviews for fit confirmation before purchasing.
Prices change frequently. See the latest deal on Amazon.