MERV 6 Air Filters | Washable EC Series Electrostatic Filters

Shop MERV 6 Electrostatic Air Filters

Popular sizes shown above. Browse custom 1-inch or custom 2-inch options for dimensions not in the standard catalog. All sizes available in both 1-inch and 2-inch depths; size reference tables are below.

What Is a MERV 6 Air Filter? MERV 5 vs. MERV 6 Explained

The MERV (Minimum Efficiency Reporting Value) rating scale is defined by ASHRAE Standard 52.2 and measures an air filter’s efficiency at capturing particles of specific sizes under controlled laboratory conditions. Higher MERV values indicate better fine particle capture efficiency but also higher static pressure drop that requires more fan energy to maintain airflow. MERV 6 sits in the mid-range of the full scale — above basic MERV 1–4 mechanical pre-filters and below the MERV 8–13 pleated filters specified for allergy and asthma concerns.

Under ASHRAE 52.2, a MERV 6 filter must capture at least 35% of particles in the 3.0–10.0 micron range and at least 20% in the 1.0–3.0 micron range. A MERV 5 filter must capture at least 20% in the 3.0–10.0 micron range. The EC Series achieves MERV 5 certification on the composite efficiency test and delivers 84–85% overall dust arrestance on the synthetic dust test used to measure real-world filtration of household particulate. This performance distinction — MERV 5 on the ASHRAE 52.2 small-particle fractional efficiency test, MERV 6–equivalent on the ASHRAE 52.1 dust spot / arrestance test — is why the filter earns the MERV 6 designation in its product name and marketing despite the legacy MERV 5 slugs in some product URLs.

For the context in which most people search “MERV 6 filter” — residential HVAC replacement, commercial air handler service, or light commercial HVAC with a need for better-than-basic dust and dander capture — the EC Series delivers exactly the performance improvement over MERV 4 that MERV 6 implies. It captures everything MERV 4 captures (particles 10 microns and larger at high efficiency) while also significantly improving capture of the 3–10 micron range that includes the fine dust fraction, mold spore fragments, and allergen-carrying pollen debris. The electrostatic enhancement means a mechanically thin media achieves this performance with low pressure drop — keeping both filtration efficiency and system airflow at acceptable levels simultaneously.

The practical choice between MERV 5 and MERV 6 in a washable filter comes down to this: the EC Series is the only AMFCO washable filter product rated above MERV 4 and below MERV 8. If you need washable and reusable, and you need better than MERV 4 foam or aluminum mesh, the EC Series is your product. If you need MERV 8 with washable construction, the R8 Series washable pleated filter is the answer.

Technical Specifications — EC Series MERV 6 Electrostatic Air Filters

All specifications from AMFCO EC Series product data and WooCommerce product records (verified April 2026). Specifications apply to all standard ECA sizes.

Standard Size Reference — EC Series MERV 6 Electrostatic Filters

A representative range of standard nominal sizes is listed below. The full EC Series catalog includes over 50 standard sizes in each depth. All sizes follow the 1/2-inch undercut rule: actual height and width each equal nominal minus 1/2 inch. Actual depth is 7/8” for 1-inch nominal and 1‑3/4” for 2-inch nominal. If your size is not listed, custom 1-inch and custom 2-inch options are available.

1-Inch Nominal EC Series Electrostatic Filters (7/8” actual depth)

2-Inch Nominal EC Series Electrostatic Filters (1‑3/4” actual depth)

Size not listed above? Custom 1-inch electrostatic filters and custom 2-inch electrostatic filters are cut to your exact specified dimensions. Contact us with your required height, width, and depth.

How EC Series Passive Electrostatic Filtration Works

The EC Series captures airborne particles through two complementary mechanisms: mechanical filtration through the polyester and polypropylene media layers, enhanced by passive triboelectric electrostatic charging of the polypropylene layer. Understanding how these mechanisms work together explains why the EC Series achieves higher efficiency than a purely mechanical filter of similar thickness and density — and why both the “no adhesive coating” and “no power required” characteristics follow directly from the physics involved.

Triboelectric Charging: The Electrostatic Effect

Triboelectric charging occurs when two dissimilar materials contact and separate. In the EC Series, airflow friction generates a static charge in the polypropylene media layer as air passes through it at rated 300 fpm. Polypropylene is a strong triboelectric material — it tends to charge negatively in contact with air while airborne particulates carry a slight positive charge from ambient atmospheric conditions. The oppositely charged particles are attracted to the charged polypropylene fibers and adhere to them, removing particles from the airstream that would otherwise pass through the mechanical media. This is the same mechanism as a statically charged balloon attracting small paper pieces or hair fibers.

Mechanical Filtration: The Polyester Layer

The polyester layer upstream of the polypropylene layer provides mechanical filtration: particles too large to navigate the fiber matrix are captured through interception and impaction independent of the electrostatic charge. The two-layer arrangement (polyester upstream, polypropylene downstream) progressively loads the media — larger particles are captured in the polyester upstream stage, relieving the fine polypropylene stage of excessive loading. This extends the service interval between wash cycles and maintains the electrostatic enhancement of the polypropylene layer longer between cleanings.

Why No Adhesive Coating

Adhesive coating is specifically not advisable for EC Series filters because any coating applied to the polypropylene layer physically blocks the surface contact between polypropylene fibers and the airstream, interfering with the friction-based charge generation that is the core of the filter’s enhanced performance. Coating a passive electrostatic filter is self-defeating — you eliminate the mechanism that makes it better than a plain mechanical filter. The EC Series achieves its 84–85% dust arrestance through electrostatic enhancement alone; no adhesive is needed or beneficial.

Charge Regeneration After Washing

Because the electrostatic charge is generated dynamically by airflow (not stored by a permanent charge deposited at the factory), washing the filter with warm water does not permanently remove the electrostatic effect. After washing and drying, the polypropylene layer regenerates its triboelectric charging capacity as normal HVAC airflow resumes. Full electrostatic efficiency is restored within the first operational cycle after reinstallation. No reconditioning spray, chemical treatment, or factory recharging is required.

Applications for MERV 6 Washable Electrostatic Air Filters

Installation

EC Series electrostatic filters install in any standard HVAC panel filter housing that accepts the nominal size. Unlike the all-metal HI and HF Series filters that can be installed in either orientation, the EC Series should be installed with the airflow direction consistent with the filter’s face grid design — check the product label or airflow arrow for correct orientation.

Before Installing

• Verify the housing accepts the nominal size; actual dimensions are nominal minus 1/2” per face (±1/16”)
• Check for an airflow arrow on the filter frame and orient to match the direction of airflow toward your HVAC system
• Confirm no adhesive coating or treatment has been applied to the filter — adhesive is not advisable and interferes with the electrostatic mechanism
• Clean the housing interior of accumulated debris from the previous filter service

Installation Steps

1. Shut down your HVAC system before accessing the filter section
2. Remove the existing filter and clean the housing interior
3. Insert the EC Series filter with the airflow arrow oriented toward the HVAC unit
4. Press firmly into place verifying all four frame edges seat flush against housing walls with no air bypass gaps at the frame perimeter
5. Secure with the housing retention mechanism and close the access panel
6. Restart the system and record the installation date to track wash intervals

Cleaning and Maintenance

The EC Series electrostatic filter is designed for regular washing with warm water. The electrostatic charge regenerates automatically after each wash cycle as the filter dries and is returned to service — no special treatment is required between washes.

Washing Procedure

1. Remove the filter from the HVAC housing
2. Take the filter to a utility sink or hose bib
3. Hold the filter with the dirty (upstream, air-inlet) face directed away from you
4. Rinse with a moderate stream of warm water washing from the clean (downstream, exit) side through to the dirty (upstream, inlet) side
5. Continue until water runs completely clear through the media
6. For heavily loaded filters, allow a brief warm soak before rinsing
7. Shake off excess water and air dry completely before reinstalling
8. Do not apply any coating, spray, or adhesive treatment at any point during or after washing

What NOT To Do

• No adhesive coating — ever. Adhesive interferes with the triboelectric charging mechanism of the polypropylene media. Coating this filter reduces, not enhances, its filtration performance.
• No high-temperature steam cleaning. Excess heat above normal water supply temperatures is not necessary and not recommended.
• No chemical dips or solvents. Not necessary; clean water restores full performance.
• Do not reinstall wet. Allow full air drying; the filter charges more effectively and reaches full electrostatic performance faster when fully dry at reinstallation.

Washing Frequency

• Residential HVAC (standard use): every 1–3 months
• Homes with pets or high dust loads: every 4–6 weeks
• Light commercial / lightly used systems: every 2–4 months
• Best indicator: visual inspection — wash when the upstream (inlet-side) face grid is visibly coated with dust; do not wait for significant airflow reduction, which indicates the filter is already heavily loaded and reducing system efficiency

Frequently Asked Questions About MERV 6 Air Filters

What is a MERV 6 air filter?

MERV 6 is a mid-range efficiency level on the MERV (Minimum Efficiency Reporting Value) rating scale defined by ASHRAE Standard 52.2. A MERV 6 filter is effective at capturing particles 3 microns and larger — including household dust, pollen, dust mite debris, pet dander, mold spores, and textile fibers — at significantly higher efficiency than MERV 1–4 filters. MERV 6 is the appropriate choice for residential HVAC systems where you want meaningfully better capture than a basic MERV 4 furnace filter, without the pressure drop penalty of MERV 8 or higher.

Why do some EC Series product pages say “MERV 5” in the URL and “MERV 6” in the product name?

The EC Series electrostatic filter was originally listed with “MERV 5” in the product slugs and URL paths, which are permanent and cannot be changed without creating redirect complications. The product names and descriptions have since been updated to accurately reflect tested performance. The EC Series achieves MERV 5 certification under ASHRAE 52.2 composite efficiency testing and delivers 84–85% dust arrestance at 300 FPM on the ASHRAE 52.1 synthetic dust test — performance squarely in the MERV 5–6 range for the large particle size categories (pollen, dust, dander, mold spores) that matter most in residential and commercial HVAC. If you are searching specifically for a MERV 6 washable filter, the EC Series is the correct product for your application.

How does electrostatic filtration work in the EC Series filter?

The EC Series uses passive triboelectric charging — the same physical principle that makes a balloon attract your hair after being rubbed. As air moves through the 4-ply media pack, friction between the polypropylene media layer and the airstream generates a static electric charge. This charge attracts airborne particulates — dust, pollen, pet dander, mold spores — to the oppositely charged fibers of the media, capturing particles that would pass through a purely mechanical filter of the same density. No external power source is required. The electrostatic charge regenerates automatically after each wash cycle as the filter dries and normal airflow resumes, restoring full electrostatic capture efficiency without any reconditioning treatment.

What is 4-ply EC Series construction?

The EC Series 4-ply media pack consists of: (1) an upstream expanded metal aluminum face guard on the air-entry side; (2) a layer of polyester media; (3) a layer of polypropylene electrostatic charging media; and (4) a downstream expanded metal aluminum face guard on the air-exit side. The two expanded metal aluminum face guards provide structural support for the composite media layers at rated airflow velocity, preventing deformation and maintaining dimensional stability. The polyester layer provides mechanical filtration; the polypropylene layer provides the triboelectric charging effect that enhances fine particle capture. The entire pack is held in a .030” thick mill-finished aluminum frame with 24 gauge aluminum face grids on both sides.

What are the actual dimensions of EC Series electrostatic filters?

EC Series filters use the same 1/2-inch undercut rule as other AMFCO filter product lines: actual face dimensions equal nominal minus 1/2 inch on height and width. A 20×20×1 nominal filter measures 19.5”×19.5”×7/8” actual (±1/16” on all dimensions). A 20×20×2 nominal filter measures 19.5”×19.5”×1‑3/4” actual. The same rule applies across every standard size: subtract 1/2 inch from each face dimension; depth is 7/8” for 1-inch nominal and 1‑3/4” for 2-inch nominal.

Does the EC Series electrostatic filter need to be connected to power?

No. The EC Series is a passive electrostatic filter — it requires no external power source, wiring, or installation beyond the standard filter slot in your HVAC system. The triboelectric charging of the polypropylene media occurs naturally through the friction of airflow during normal system operation. This distinguishes the EC Series from electronic air cleaners and powered electrostatic precipitators, which require a power source. Install the EC Series filter exactly like any standard panel filter — slide into the housing and the electrostatic effect works automatically.

Can EC Series electrostatic filters be coated with adhesive?

No. Per AMFCO manufacturer specifications, it is not advisable to apply any adhesive coating to EC Series electrostatic filters. Coating the polypropylene media with adhesive interferes with the passive triboelectric charging mechanism — the coating blocks the friction-based charge generation that is the core of the filter’s enhanced particle capture performance. Do not apply Filter Coat, tackifier, or any other adhesive or spray treatment to EC Series filters.

How do I wash an EC Series MERV 6 electrostatic air filter?

Remove the filter from the housing and hold it with the dirty (air-inlet) face away from you. Rinse thoroughly with a moderate stream of warm water, washing from the clean (exit) side through to the dirty (inlet) side, until the water runs completely clear. For heavily soiled filters, allow a brief warm soak before rinsing. Shake off excess water and allow the filter to air dry completely before reinstalling. Do not apply any treatment, coating, or spray during or after washing. The electrostatic charge regenerates automatically as the filter dries and normal HVAC airflow resumes — no reconditioning is required.

How often should I wash an EC Series electrostatic filter?

In most residential HVAC applications, washing every 1–3 months is the right interval. Homes with pets, heavy foot traffic, or dusty environments should wash monthly or every 6–8 weeks. Lightly used systems or vacation homes with lower particulate loads can often go 3–4 months between washes. Visual inspection is the best guide: wash when the aluminum face grid is visibly coated with grey/brown dust. A useful practical indicator is when your HVAC blower seems to be working harder or airflow from registers feels reduced compared to a newly washed filter.

Why Choose EC Series MERV 6 Washable Electrostatic Air Filters?

The EC Series is the only AMFCO washable filter that uses passive electrostatic enhancement to achieve MERV 5–6 performance without the mechanical density that would raise static pressure drop to MERV 8+ levels. The 4-ply polypropylene and polyester media pack delivers 84–85% dust arrestance at 300 fpm — capturing pollen, pet dander, fine dust, and mold spores that standard MERV 4 aluminum mesh or foam filters miss — while maintaining the low resistance that residential blower motors and commercial air handlers require for efficient operation. No external power, no media replacement, no recurring filter cost beyond the initial purchase.

The .030” thick aluminum frame with 24 gauge face grids provides the structural rigidity to maintain critical face-dimension tolerance (±1/16”) through decades of wash cycles, keeping the filter properly seated in the housing without air bypass gaps that defeat filtration. The aluminum construction is fully corrosion-resistant and appropriate for HVAC systems including outdoor-exposed make-up air applications and humid environments where cardboard-framed disposable filters deteriorate. Made in the USA by American Metal Filter Company, every EC Series filter is built to the same dimensional and construction standards across the full catalog of 50+ standard sizes in 1-inch and 2-inch depths.

If you need performance between basic MERV 4 and full MERV 8 with washable permanent construction, the EC Series is the correct choice. Remember the two care requirements specific to electrostatic filters: no adhesive coating (it interferes with triboelectric charging) and allow full air-drying after washing before reinstalling (the electrostatic charge regenerates naturally with drying and airflow). Both follow directly from how electrostatic filtration works — and both mean that proper care of this filter is simpler, not more complex, than any disposable media alternative.