18 x 20 x 1 Permanent Washable Residential Air Filter

Product ID V41S.011820
18 x 20 x 1 Permanent Washable Residential Air Filter product photo Front View thumbnail
Actual Size: 17 1/2" x 19 1/2" x 3/4
  • Actual Size: 17 1/2" x 19 1/2" x 3/4 (more info)
  • MERV not rated
  • Built for long-term use
  • Wash Every 30 Days
  • Ships in 5 Business Days
View Terms and Conditions
  • 45.38 1-Pack (45.38 each)

IMPORTANT: NDUSTRIA™ infrared heaters are transported on a pallet(s) via a full-size or short semi-trailer. Please be aware that a forklift may be required to unload. Also, delivery may not be available in certain residential areas. Please contact NDUSTRIA™ for questions on shipping or for special shipping instructions.

Why Should I Change My Air Filter?

If you have postponed changing the air filter in your unit more than once, you probably do not realize how important it is and why. Over time, the fan motor could burn out, causing the system to overheat and ultimately fail. A new filter protects the system and helps it run years longer.

Product Details

Nominal Size
20" x 18" x 1"
Actual Size
17 1/2" x 19 1/2" x 3/4"
Air Filter Type
Lead Time
4 Business Days

18 x 20 x 1 Residential Washable Air Filter

*Listed Filter Size is Nominal (Actual size is up to 1/2 inch smaller on all dimensions)

These quality filters are built to last a lifetime. They are interchangeable with 1 inch disposable filters and can be used again and again. The secret behind the filter's performance is its patented stage loading/peak and valley design. Instead of face loading (particles captured on the outer surface of the filter) the filter uses stage loading, with each stage capturing progressively smaller particles inside the filter. This design enables the filter to maintain its performance over the years. Unlike some permanent air filters, the filter uses no foam that may clog, degrade and restrict air flow, so it can provide a lifetime of dependable service.

  • Never have to hassle with disposable filters that will end up in a landfill. Easy to install - installs like any disposable filter.
  • Easy to maintain - no need to buy oil sprays or adhesives to enhance filter effectiveness.
  • Easy to clean - simply backwash every month with cold water. No expensive air filter cleaners needed.
  • Factory made to fit with no hassles or problems cutting and sizing adjustable filters.

This filter has no MERV rating.

  • Framing: Custom assembled aluminum frame designed for strength and durability.
  • Layer A (Front): Corrugated galvanized lathe designed to hold fabrics in framing under high velocities of air flow.
  • Layer B: This layer is 100% synthetic air filter media design with large openings to allow maximum air flow with filtering capabilities to capture larger particles. Made of high density polypropylene, this layer starts the electrostatic reaction that holds particles to the fabric.
  • Layer C: Proprietary 100% synthetic polypropylene woven mesh filter media designed to catch the smallest of particles.
  • Layer D (Back): Corrugated galvanized lathe designed to hold fabrics in framing under high velocities of air flow.

Installation and Care Instructions

  • Installation:
    • The dark blue side is the front of your air filter
    • When installing, the front side faces away from the unit
    • For indoor installations, the front side faces the room
  • Maintenance:
    • No special cleaners are needed to wash your filter
    • A simple back wash every 30 days will suffice
    • Spray through the gray side of the filter to remove dust and other particles
    • Make sure the filter is completely dry before installing it back into your unit