Nordic Pure MERV 15 Air Filters: Sizing and Compatibility Guide

Best for: Homes needing particle capture and odor neutralization

Pros

• Activated charcoal layer
• MERV 15 synthetic media
• Universal 4-inch track fit
• Manufactured in the USA

Cons

• Too thin for 5-inch housings

The Nordic Pure 16x25x4 Pleated MERV 15 is built for residential and commercial air handling systems that utilize standard 16×25 return filter racks. While the nominal size is labeled as 16x25x4, the actual dimensions measure 15 1/2 x 24 1/2 x 3 5/8 inches. The core filtration layer uses electrostatically charged synthetic poly blend media rated at MERV 15, which captures microscopic particulates for hospital-grade air cleaning. Unlike standard particle-only filters, this model integrates an activated charcoal flat panel across the frame, introducing odor adsorption capabilities to eliminate smoke, cooking aromas, and pet smells without restricting airflow.

Physical depth is the defining factor when determining whether this model matches your HVAC installation. The 3 5/8-inch actual thickness fits standard four-inch track assemblies found in typical furnace and central air conditioner return plenums. However, if your system utilizes a proprietary Honeywell or Lennox media cabinet that originally took a nominal 16x25x4 filter with a 4 3/8-inch depth, this standard frame will sit too loose. For those specific deep cabinets, Nordic Pure manufactures a dedicated 16x25x5 replacement, making this 3 5/8-inch unit suitable exclusively for standard four-inch channels.

Supplied as a 2-pack, this filter is manufactured in the United States using moisture-resistant frame components. Nordic Pure recommends replacing these four-inch deep-pleat filters every three to six months, depending on your home environment and fan runtime. Because it includes activated carbon media, it serves homeowners who want particle defense combined with chemical odor removal.

• Actual frame dimensions measure 15 1/2 x 24 1/2 x 3 5/8 inches.
• Electrostatically charged synthetic pleated media paired with an activated charcoal flat panel.
• Engineered for high-purity air needs in residential and commercial systems.
• Manufactured in the USA and supplied in a 2-count package.

Best for: Honeywell and Lennox 16×20 media housings

Pros

• Exact 4 3/8-inch depth
• Rigid moisture-resistant frame
• Laboratory-grade MERV 15 media

Cons

• Supplied as single unit

The Nordic Pure 16x20x5 Honeywell Lennox Replacement is engineered for homeowners with proprietary media filter cabinets from Honeywell or Lennox. This model carries a nominal size of 16x20x5 H, but its actual physical dimensions measure 15 7/8 x 19 5/8 x 4 3/8 inches. The 4 3/8-inch depth is a deliberate engineering choice: traditional five-inch media cabinets from Honeywell and Lennox are narrower than standard five-inch enclosures. Using an actual 4 3/8-inch frame ensures the filter slides securely into the cabinet rails without bending or leaving perimeter air gaps.

Homeowners evaluating a honeywell air filter setup often face confusion when reading cabinet door stickers, which occasionally list nominal depths of four inches while actually requiring a 4 3/8-inch insert. This Nordic Pure replacement bridges that exact gap. It replaces both nominal 16x20x5 and nominal 16x20x4 filters that feature an actual 4 3/8-inch measurement. If your cabinet tracks have an interior clearance narrower than 4 3/8 inches, a standard four-inch filter with a 3 5/8-inch depth must be selected instead.

The filter features electrostatically charged synthetic poly blend pleated media designed for high-efficiency residential and commercial applications. The heavy-duty perimeter frame supports maximum dust-holding capacity while resisting moisture buildup. Supplied as a single filter, Nordic Pure recommends an operational service life of three to six months under standard residential operating conditions.

• Actual dimensions measure 15 7/8 x 19 5/8 x 4 3/8 inches.
• Direct fit for Honeywell and Lennox media enclosures requiring 4 3/8-inch depth.
• High-efficiency synthetic poly blend pleated media rated MERV 15.
• Manufactured in the USA for commercial and residential air conditioners and furnaces.

Best for: Standard residential 16×20 4-inch return tracks

Pros

• Standard 3 5/8-inch depth
• MPR 2800 performance equivalence
• Includes two filters

Cons

• Incompatible with Honeywell 5-inch racks

The Nordic Pure 16x20x4 Pleated MERV 15 provides high-performance air filtration for HVAC return ducts configured for standard four-inch filters. The nominal 16x20x4 dimensions translate to an actual physical size of 15 1/2 x 19 1/2 x 3 5/8 inches. This 3 5/8-inch thickness is the industry baseline for universal four-inch filter tracks. The synthetic pleated media achieves a MERV 15 rating, which Nordic Pure notes is equivalent to an MPR 2800 rating, delivering filtration suited for capturing sub-micron allergens, fine smoke, and airborne bacteria.

Precise cabinet measurement is crucial when deciding which nordic pure air filter to buy for a 16×20 opening. If your furnace or air handler uses a specialized Honeywell or Lennox media box that calls for a 4 3/8-inch actual thickness, installing this 3 5/8-inch frame will result in a 3/4-inch space inside the housing. That clearance permits unfiltered return air to circumvent the filter pleats entirely. For standard four-inch sheet metal housings, however, this model provides an airtight fit that prevents bypass while maintaining steady static pressure across the system.

This product comes packaged as a 2-count box, giving users up to a full year of filtration when following the manufacturer recommendation of changing media every three to six months. Constructed from electrostatically charged synthetic material, the media resists moisture and will not support microbial growth on the filter frame.

• Actual dimensions measure 15 1/2 x 19 1/2 x 3 5/8 inches.
• MERV 15 synthetic pleated media equivalent to MPR 2800.
• Engineered for standard residential 4-inch filter housings.
• Made in the USA and packaged as a convenient 2-pack.

Best for: Trion Air Bear whole-house air cleaner units

Pros

• Matches part 266649-103
• Full 4 15/16-inch depth
• Economical 4-pack supply
• Heavy-duty construction

Cons

• Too thick for Honeywell cabinets

Best for: Square 20×20 Honeywell and Lennox cabinets

Pros

• Direct 4 3/8-inch track replacement
• Electrostatically charged fibers
• Convenient 2-pack supply

Cons

• Too narrow for Air Bear cabinets

The Nordic Pure 20x20x5 Honeywell Lennox Replacement addresses square HVAC filter housings commonly found in mid-sized residential and light commercial systems. Branded under model designation 20x20x5 H, its actual dimensions measure 19 5/8 x 19 7/8 x 4 3/8 inches. The frame is constructed to serve as a direct swap for Honeywell 20x20x4 housings as well as proprietary 5-inch units that require an actual depth of 4 3/8 inches. It also matches systems specified for MPR 2800 performance.

Dimensional comparison is critical when looking at square five-inch filters. Homeowners occasionally mistake this model for the 20x20x5 Air Bear variant, but the internal sizing is distinct. This Honeywell and Lennox replacement has an actual thickness of 4 3/8 inches, whereas an Air Bear housing requires an actual depth of 4 15/16 inches. Attempting to install this filter into an Air Bear rack leaves a 9/16-inch air gap, while trying to force a 4 15/16-inch filter into a Honeywell housing will crush the pleats. Matching the 4 3/8-inch specification ensures zero bypass and protects equipment like a rheem air filter cabinet or furnace blower assembly.

Each shipment includes two filters weighing 7.5 pounds combined, reflecting the dense structural pleating and heavy-duty frame construction. The electrostatically charged synthetic fibers attract tiny airborne contaminants without relying on chemical additives. The replacement interval remains consistent with Nordic Pure recommendations at three to six months.

• Actual measurements are 19 5/8 x 19 7/8 x 4 3/8 inches.
• Direct replacement for Honeywell 20x20x4 and 20x20x5 cabinets with 4 3/8-inch actual depth.
• MERV 15 filtration media performance equivalent to MPR 2800.
• Packaged as a 2-count set with heavy-duty moisture-resistant construction.

Best for: Standard 20×25 4-inch return air ducts

Pros

• True 3 5/8-inch thickness
• High-capacity deep pleat design
• Packaged in 2-count box

Cons

• Will bypass in 5-inch housings

The Nordic Pure 20x25x4 Pleated MERV 15 is built for high-capacity return air cabinets that accommodate 20×25 filter frames. The nominal 20x25x4 size corresponds to an actual measurement of 19 1/2 x 24 1/2 x 3 5/8 inches. The deep-pleat geometry expands the active surface area of the media, allowing it to capture high volumes of airborne particulate matter while minimizing initial static pressure drop across the ductwork. Nordic Pure assigns this MERV 15 filter an equivalence of MPR 2800, targeting sub-micron particles such as smoke, smog, and fine respirable dust.

When measuring your existing filter, verify the depth dimension carefully. If your 20×25 housing is a Honeywell unit designed for a 4 3/8-inch filter, this 3 5/8-inch frame will not seal properly along the top and bottom channels. Nordic Pure explicitly advises that users replacing a 4 3/8-inch deep filter should order the dedicated 20x25x5 Honeywell replacement (actual dimensions 19 7/8 x 24 7/8 x 4 3/8 inches) rather than this standard four-inch unit. However, for universal four-inch filter racks, this frame slides into position with tight tolerances.

For homeowners comparing deep-pleat disposable media against options detailed in a k&n home air filter guide, this disposable synthetic filter offers high single-pass efficiency without requiring cleaning solvents or wash cycles. Packaged as a 2-pack, it is manufactured in the United States and recommended for changeouts every three to six months.

• Actual dimensions measure 19 1/2 x 24 1/2 x 3 5/8 inches.
• Electrostatically charged synthetic pleated media equivalent to MPR 2800.
• Engineered for standard 4-inch deep return air plenums and furnace cabinets.
• Manufactured in the USA and packaged as a 2-pack.

The Nordic Pure 20x20x5 Air Bear Replacement is designed specifically for whole-house air cleaner cabinets manufactured by Trion Air Bear. Labeled under model number 20x20x5 AB, this filter carries an actual physical size of 19 11/16 x 20 11/16 x 4 15/16 inches. Its 4 15/16-inch actual depth makes it the thickest filter in the Nordic Pure 20×20 lineup, engineered to fit Air Bear housing part number 266649-103. The substantial depth allows for expansive pleat spacing that handles significant airflow volume while capturing fine particulates.

It is vital not to interchange this model with the 20x20x5 Honeywell Lennox unit. Although both are sold under the nominal 20x20x5 banner, the Air Bear model is 9/16 of an inch thicker (4 15/16 inches versus 4 3/8 inches) and slightly wider in length and width (19 11/16 x 20 11/16 inches versus 19 5/8 x 19 7/8 inches). Installing an Air Bear filter into a Honeywell cabinet will result in mechanical interference, preventing the cabinet door from latching. Conversely, using a Honeywell replacement inside an Air Bear cabinet creates significant perimeter leakage.

Packaged in a convenient 4-pack, this model provides multi-season maintenance coverage for homeowners. The synthetic poly blend pleated media achieves a MERV 15 rating, suited for residences requiring clean-room air filtration to manage severe allergies or respiratory concerns. Like all Nordic Pure filters, it is produced in the USA and carries a recommended replacement cycle of three to six months.

• Actual measurements are 19 11/16 x 20 11/16 x 4 15/16 inches.
• Engineered specifically to fit Trion Air Bear cabinets and part number 266649-103.
• Dense MERV 15 synthetic media provides pro-strength HVAC filtration.
• Manufactured in the USA and supplied as a high-value 4-pack.