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1. What does “electrostatic” mean?

2. Why does this type of permanent, washable furnace air filter cost more?

3. With a pleated filter, I can just throw it out and put a new one in my system. Wouldn’t this be easier than washing a filter and a lot less costly?

4. How do I know which washable air filter is the right one for my use?

5. What makes your furnace filter better than your competitors?

6. Do I need to plug my electrostatic in to an outlet?

7. Where can I purchase my Permatron Air Filter?

8. What size filters do you manufacture?

9. How do I measure what size air filter I need?

10. How can I tell that my air filter is working?

11. How do I return my air filter because of a warranty issue?

12. How do I install my air filter?

13. Does my air filter have a directional air flow?

14. How do I clean my air filter?


1. What does”electrostatic” mean?

A static electric charge (positive or negative), or having a charge which remains local and permanent. This property does not diminish or disappear over time, and is not an additive that can wash out from filtration media, nor is it created by the addition of high voltage electricity. Airborne particles are attracted to the filtration media like iron filings to a magnet. Particles remain attached to the media until they are rinsed away.

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2. Why does this type of permanent, washable furnace air filter cost more?

Built with the finest quality permanent/washable materials and construction design, this furnace filter is made to last the life of your HVAC system. There are no replacement parts and nothing to dispose of and environmentally friendly. This is a one time cost, and gives you the least cost over the product’s useful life.

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3. With a pleated filter, I can just throw it out and put a new one in my system. Wouldn’t this be easier than washing a filter and a lot less costly?

Disposable furnace filters, which use impingement filtration, tend to face-load over time due to particle buildup. This causes increased resistance to airflow if not changed or cleaned regularly. Clogged furnace filters can cause upset of air flow balance, resulting in overheating and costly damage to a blower motor or compressor. Our woven filter media allows air to flow through. The particles, attracted to the electrostatic fibers in the direction of air flow, build up on the fibers without face loading. Permanent/washable electrostatic filters are a one-time cost and environmentally friendly. If you add up the time and material cost of buying new throw away filters each month, you’ll see that our permanent furnace filter gives you the least cost over the product’s useful life. Our washable air filters are simply rinsed and placed back into your system. Our air filters are a”green” product!

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4. How do I know which washable air filter is the right one for my use?

Furnaces and air conditioners are not all alike; some have different air flow requirements for optimum efficiency. No one filter is effective in all circumstances. Today’s equipment manufacturers are using advanced sensitive technology. With 90 Plus efficiency come stricter air filter requirements. The same can also be said for homes with older HVAC equipment or heat pumps, with limited airflow of less than 900 CFM. Homeowners should not just insert an air filter into their system without checking on the size of the ductwork and the pressure drop/air velocity requirements. These requirements can be found in the operating manual of the equipment.

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5. What makes your furnace filter better than your competitors?

As a pioneer in the electrostatic filter market since 1957, our permanent, washable air filters were designed with the finest quality materials and workmanship. They will remove the most airborne irritants with the least resistance to air flow, offer easy cleanability and a long useful life. The following is a brief guideline to assist you in choosing an electrostatic air filter for your furnace:

The highest arrestance does not necessarily mean the most efficient filter. High arrestance can mean higher resistance to airflow (clogging) – check a complete copy of test data for initial resistance. Many high arrestance efficiency averages are the result of face loading (dirt build-up) and blocked airflow. Filters with numerous stacked media layers and no drain ports in the frame allow residual dirt build-up inside, seriously clogging the filter. Inexperienced manufacturers/ assemblers often choose materials and methods based on cost alone, with little regard for the quality or durability of the end product.

Long term product use, effectiveness and customer satisfaction comes from filter design based on proven engineering principles and precision construction. HVAC/furnace equipment specifications vary with different air flow requirements for optimal efficiency – no single air filter model is effective in all possible installations.

When comparing test data, compare correctly – peak scores are not as representative of performance as are average scores, and dirt holding capacity is important because it indicates how much dirt the filter holds before clogging. Be sure the manufacturer has a proven history of standing behind product warranties.

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6. Do I need to plug my electrostatic in to an outlet?

No. The static charge is inherent in the filter media.

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7. Where can I purchase my Permatron Air Filter?

Homeowners can purchase a Permatron Air Filter from their local heating and air conditioning contractor. Or you can call us toll-free at 1-800-882-8012 or email us at and we’ll be happy to refer you to a mail order catalog or website, HVAC contractor or duct cleaner in your area. Custom sized air filters are nonreturnable.

Purchase Permatron Air Filters Online

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8. What size filters do you manufacture?

We manufacture all sized filters. Our air filters come in 25 standard NOMINAL sizes (undercut 1/2″ less than stated size per industry standards) as well as any custom EXACT size (nonreturnable) you need, including those with fractions. Standard Sizes Available:

10×20 14×20 16×24 18×30 12×30 18×24     25×25
12×12 14×24 16×25 20×20 12×36 18×25
12×20 14×25 18×18 20×24 15×20 20×30
12×24 14×30 18×20 20×25 16×20 24×24

Filter thickness is available in ¼”, ½”, 1″ and 2″.

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9. How do I measure what size air filter I need?

A. Check to see if your furnace has an existing air filter in it. If so, does it fit properly? If it contains a disposable air filter, are there any squashed corners or has the filter been forced into the system to fit? If not, the size should be labeled on the side of the filter. That is the replacement size you should be using when ordering your new Permatron air filter. The size should read something like 16″ X 20″ X 1″. If the size is not clearly labeled, you can measure the filter with a ruler. Keep in mind that many disposable filter manufacturers undercut their filters by anywhere from ¼” to ½”. In most cases, you should be able to use closest standard size. I.E., a filter measuring 15-3/4″ X 19-3/4″ exact could be replaced with a 16″ x 20″ Permatron Filter. Our standard sized filters are undercut by 1/2″. Ask for “nominal” when ordering. If the filter does not fit properly, or you do not have an existing air filter in your system, you will have to measure the duct opening. You will need a flashlight and a stiff tape measure. Look inside the section of the furnace where the filter should be located. You should have a 1″ filter track or opening where the filter slides into. Your filter should cover the duct opening. Measure the height and width of the duct opening; allow a bit of overlap if you have room. That is the exact size that you need to order your new Permatron Filter. Ask for “exact” when ordering.

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10. How can I tell that my air filter is working?

Air filters are designed to remove airborne particles as the air from your home recirculates through your ventilating system. Air filters can not remove dust particles that have already settled onto your furniture, and do not take the place of vacuuming and dusting. Unusually high levels of dirt might be caused by remodeling/construction, repairs on ventilation system breaking built-up dirt loose, new home furnishings generate high lint levels, open windows suck in dirt from outside air, clothing dryers vent indoors, or your filter has become coated with oils from cooking, air fresheners, professionally cleaned furnishings or cigarette smoke. Your air filter will work most effectively if your recirculating fan is turned on, as well as your heat or air conditioning. Your filter might not look very dirty on the surface because dirt is distributed throughout several layers of filter media. Remember that most airborne particles are not visible to the naked eye. Rinse the filter in a white tub and you will see the dirty water running out.

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11. How do I return my air filter because of a warranty issue?

Permatron takes pride in the quality and workmanship of our products. All are built to give years of trouble-free service. Any filter found to be defective in workmanship or materials, will be repaired or replaced without charge by Permatron, with a prepaid shipping fee of $29.95.   The warranty period begins from the date of purchase and does not cover damage caused by excessive heat, disassembly, rough handling or improper installation. DO NOT take the unit apart for cleaning, as this is unnecessary. With proper care and regular cleaning, your Permatron filter should last many years. Permatron Corporation makes no medical or health claims other than that the filter will effectively remove particles from
the air.

As a reminder, our warranty only covers manufacturer’s defects. Take a photograph of your filter clearly showing the defective area and email it to, using HOMEOWNER WARRANTY CLAIM in the subject line. Customer service will respond to your request promptly.

Valid manufacturer’s defect claims will receive a RETURN AUTHORIZATION NUMBER from Permatron Corporation to include on future correspondence.  A replacement filter will be shipped to you after you supply the following information:  A photo of the product label, showing model and size.  Include your shipping address and credit card payment of $29.95 for the shipping fee.

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12. How do I install my air filter?

Standard and custom sizes are available to fit any furnace. Install the filter by simply removing your existing disposable filter and sliding in your permanent new air filter. Furnaces with hammock style filter racks can be adapted easily. Check the system requirements for pressure drop/air velocity restrictions (i.e., Initial Resistance to Airflow 0.11 inches w.g.). These requirements can be found in the operating manual of the equipment.

Some air filter models are designed to have a directional air flow. Check the label on your filter frame before you install it. The filter is designed to be installed so that the air flows in the same direction, depending on how your HVACR system was designed to work. 

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13. Does my air filter have a directional air flow?

Depending on how an air filter is manufactured determines whether or not there is a specific direction that you need to install your air filter into your furnace so that it works properly.

Some of our filters are designed with stacked media encased in a 1″ frame, like our LifeStyle Plus® MF and LR models.   The filter media is layered so that the same media is the outside layer on both sides of this filter.  There is 1 layer of different/thicker mediain the center.  The media in the center depends on what efficiency the filter model is trying to achieve, i.e., low resistance or maximum filtration.    These filter do not have a directional air flow, since the air flows though the same media, no matter what side it flows through.

Some of our filters are designed with our exclusive Accumulator Chamber® construction.  This filter design represents a mini filter bank, or has been referred to as 3-stage filtration.  The outer steel frame holds (2) 1/4″ steel framed panels inside, which are separated by air space which we call our Accumulator Chamber.   In these filters the 1st panel (prefilter) made of just polypropylene media allows air to flow through, enhancing its electrostatic charge.  If excess (called face loading) particulates build up on the prefilter, they tend to break off, allowing air flow to sweep them through the prefilter into the Accumulator Chamber.  The 2nd panel (afterfilter) sometimes contains additional media, like nonwoven polyester or foam or supporting wire encased in polypropylene.   The more efficient afterfilter captures the smaller particles that were not captured by the prefilter.   These filters would have a directional air flow (air flows through the prefilter to the afterfilter), because they contain a lower resistance prefilter and a higher resistance afterfilter.  So when they are washed, they should be back flushed for best results.  That means water flows through the afterfilter to the prefilter.

Filters that include a directional airflow are the DustEater® and Model HFA.   The Easy Flow and Model IN do have the Accumulator Chamber construction, but both interior panels contain only polypropylene, so there is no directional air flow since the media is the same throughout the whole filter. 

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14. How do I clean my air filter?

Clean monthly by rinsing your filter with running water. Particles in the Accumulator Chamber as well as on the electrostatic panels wash out easily through the drainage ports in the frame. For tough dirt and grease, use a mild detergent (i.e., 409 or Simple Green) and rinse thoroughly with warm water.

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