Where To Buy Ac Air Filters Near Me

The research

Who this is for
What is a MERV rating?
How to choose a filter past its MERV rating
A perfectly good HVAC filter: Nordic Pure MERV 12
Two other filters that should do a fine job
How often should I replace my filters during wildfire smoke events?
Footnotes

Who this is for

Nearly HVAC systems use a standard 1-inch-thick filter, then we focused exclusively on 1-inch medium-efficiency MERV filters. These are installed either in wall-mounted air-return vents (most common in the South), or at the air handler (more common in the Mid-Atlantic and northern states, where the air handler is often placed in the basement, near the furnace). A correctly sized 1-inch MERV filter simply rests behind a bracket at the render annals; if you're not sure what size y'all need, bank check the narrow side of an existing filter for the dimensions (like "sixteen x 25 x ane").

If your HVAC arrangement uses a thicker filter (usually in the iv- to 5-inch range, and usually mounted at the air handler), it was likely designed specifically for medium-efficiency MERV filtration. You don't demand our advice; simply replace the existing filter with one that has the same specs.

What is a MERV rating?

MERV stands for Minimum Efficiency Reporting Value, and is a mensurate of how well a filter removes particulates from the air. In that way it's akin to the more familiar HEPA rating used on air purifiers. And like the test for HEPA rating, MERV testing mensurate a filter's efficiency—the percent of particles it captures—in a unmarried laissez passer. Air is loaded with particulate matter, sent through the filter a single fourth dimension, and the results measured. In real-globe apply, with the air in your home constantly recirculating through the ducts and passing through the filters each time, the cumulative effect of the filters rises.

But MERV is unlike in some key means. Start, instead of being a unproblematic pass-fail measure similar HEPA (a filter is either HEPA-rated or information technology's not), MERV ratings fall on a scale from 1 to sixteen, with college numbers indicating meliorate performance.

Besides unlike HEPA, MERV tests measure particulates of dissimilar sizes, from 0.three micron (very minor and difficult to filter—the size HEPA tests measure) up to 10 microns (relatively big and like shooting fish in a barrel to filter). MERV also doesn't have a target percentage for removal, the way HEPA does. Instead, the actual pct removal is recorded for each of 12 particle sizes, and these numbers are referenced against a functioning tabular array to make up one's mind the appropriate rating.

So when yous wait at the full spectrum of what'southward floating around in the air in your firm, MERV ratings reflect a filter's performance on all of it. Higher numbers indicate a ameliorate filtration of the smaller particles, similar pollen and fume, that cause many respiratory bug. And medium-efficiency MERV filters in the 8 to thirteen range—the kind nosotros would go—can remove 90 percentage or more than of these. (For a really thorough explanation of how MERV ratings are calculated, visit the website of the National Air Filtration Association.)

One more thing: Some companies, including major filter manufacturer 3M/Filtrete and major filter retailer Domicile Depot, use their own rating conventions (MPR past Filtrete and FPR by Dwelling Depot). Both merits to be based on the American Club of Heating, Refrigeration, and Air-Conditioning Engineers'southward ASHRAE 52.2 standard that's used to set MERV ratings, just neither company provides an hands accessible explanation of how its ain ratings differ from or compare with MERV. (Filtrete does print MPR and MERV equivalents on the frames of its filters, just you lot tin't see that until you've actually got ane in your easily.)

After we inquired, Filtrete replied that its MPR filters capture more of the very small particles (0.3 to one micron) than equivalent MERV-rated filters when tested to ASHRAE 52.2 protocol, and shared a test summary that backs this up; on the larger particles (ane to 10 or more microns), MERV and MPR performance was nearly identical. Filtrete said MPR 1900 is equivalent to MERV xiii, MPR 1500 to MERV 12, and MPR 1000 to MERV 11.

Home Depot shared a basic comparative chart but no exam data or protocols; information technology equates FPR 9 and 10 to MERV 12, FPR 7 and 8 to MERV eleven, and FPR 6 to MERV 10.

How to choose a filter by its MERV rating

A stack of the filters we tested — Photo: Michael Hession

To make up one's mind what filter nosotros'd buy, nosotros needed a more pragmatic explanation of MERV, then nosotros turned to Kathleen Owen, a inquiry engineer specializing in air filtration. Owen almost literally wrote the book on MERV: In the 1990s she helped define the American Society of Heating, Refrigeration, and Ac Engineers'southward ASHRAE 52.2 standard that's used to set the ratings. She later chaired the ASHRAE 52.two committee, which regularly updates the standard to address changes in filter technology.

In a chat virtually the most mutual filter levels for sale at retail, MERV 1 through 16, Owen said this range "gets y'all from filters that might catch a golf ball—I'm exaggerating a niggling bit—up to filters that will catch almost everything." Owen added, "I like to tell people that each of those filters has a purpose."

• MERV 1 to 4 (and unrated): Filters like the MERV 4 East-Z Flow, MERV 2 True Blueish, MERV 1 Filtrete Bones Cut-To-Fit, and the unrated Flanders, are the cheapest (some under $1 apiece) and most basic MERV-rated filters. Their purpose is to go on particles larger than 10 microns—including pet hair (but non dander), carpet fibers, and heavy grit—from clogging the heating/cooling coils and ducts in your HVAC system. They have little to no bear upon on fine particulates like pollen and fume, so they will not practice much to ease respiratory issues. But even with their limitations, these filters aren't pointless. They prolong the life of your equipment and help continue it running efficiently in the heating and cooling seasons. "Think of how important your screen door is in summer when there's flies out," Owen said. If you are reading this guide, you probably care too much near air quality to consider 1 of these filters, merely if you're living (or vacationing) in a rental and don't want to invest much—specially if the existing filter is problematically old or dingy—replacing it with a MERV one to 4 filter would exist a fine quick fix.

• MERV v to seven: Owen said filters in this range (similar this MERV 7 Nordic Pure) were created equally an comeback on the basic MERV 1 to 4 filters and designed to likewise filter out midsize particles (three to 10 microns, which includes well-nigh pollen and mold spores) that could encourage mold growth on heating/cooling coils. These filters are not as widely sold as the lower and higher MERV-rated filters in hardware stores, but they can be institute online easily. There's nothing wrong with these types of filters; we just didn't focus on them as much as we did those in the 8 to thirteen range more often than not because this form, past comparing, usually isn't any cheaper, doesn't perform quite as well, and oftentimes isn't as piece of cake to detect.

• MERV 8 to 13: This is the category we'd recommend for people who intendance about indoor air quality, and in that location are many equally good examples, such as the Nordic Pure MERV 10 and MERV 12, the Honeywell FPR nine, and the Filtrete 1500. (For more detail on these models, run across the A perfectly good HVAC filter and Two other filters that are also fine sections.) We focused on filters in the MERV eight to 13 range considering they are good to splendid at removing fine particulates (as pocket-sized every bit 0.3 to 3.0 microns in diameter, including smoke and exhaust particles and leaner), plus anything larger. This MERV range, Owen said, "covers most of the stuff that people are probable to breathe in unless they're really shut to the source." The EPA says filters rated MERV 7 to 13 "are probable to exist nearly equally effective as true HEPA filters at controlling well-nigh airborne indoor particles." The higher end of the range, MERV 11 to xiii, removes xx-plus to 50-plus percent of the very smallest, 0.3-to-ane.0-micron particulates, and filters in this range are especially pop. An NIH literature review indicates that filters in this range can significantly reduce indoor fine-particulate pollution and alleviate some respiratory ailments.

• MERV 14 through sixteen: These are specialized filters that require a purpose-built HVAC system; they're widely used in hospitals and some commercial and industrial environments, only more often than not non in homes.

So why doesn't everyone get a MERV 8 to 13 filter? Beyond their higher cost, in that location is also a concern your equipment might not be able to handle them, according to engineers we interviewed from ii of the major HVAC manufacturers: Jay Ayers of Trane and Doug Powell of Carrier. They (and Owen) all told usa MERV filters in this range restrict airflow more than than low-MERV filters, as measured by the drop in air pressure the filters create when installed. That can potentially strain your equipment.

Powell noted that, "You lot have a fair amount invested in your HVAC organization, and unless you know how much pressure drop you have in it and how much more it tin handle, you could finish up shortening the life of your blower. And a blower's non cheap." Ayers said, "That's the danger of looking at 1-inch filters and trying to go college-efficiency and do the job that's needed for allergies: You lot run the adventure of actually damaging your blower and your HVAC arrangement." (If you are concerned near this, to exist absolutely punctilious you can hire an HVAC firm to measure force per unit area driblet in your system.ⁱ)

Against these warnings, however, is a mountain of owner testimony that MERV 11, 12, and fifty-fifty xiii filters have worked just fine in their systems for years. Too, an often-cited comprehensive independent exam of MERV viii to 13 filters' furnishings on HVAC airflow and energy consumption (a proxy for how hard the equipment is working) ended that even "if no accommodations are fabricated for the greater pressure drop of high-MERV filters, air flow and energy penalties are not likely to be astringent—at to the lowest degree, non until the filter is loaded with dirt."

Nosotros experience the manufacturers' concerns are a scrap overcautious, in function considering a recent innovation in air filters permits high MERV ratings (11 to thirteen) with low pressure driblet.² So-called electret filters use a mat of fibers that are electrostatically charged. The charge helps attract airborne particles (rather than just passively impeding them). Every bit a result, the mat can exist more porous, causing improve airflow and a smaller pressure drop. Yet, Owen emphasized, electrets get less efficient over time, oft significantly so. "Electret media will drop in efficiency upon utilize, sometimes by equally much as 50 percent," she said. "Basically what happens is the tiny particles—we're talking 40, 50 nanometers, which in that location are gazillions of in the air—will glaze the charged fibers and keep them from alluring larger particles." That means regularly replacing electrets is absolutely primal to maintaining good filtration, and most come with 60- or 90-day replacement schedules. If you run your system year-round, that'due south potentially half-dozen filters a yr.

Given all this, we decided that if we were buying new filters today, we'd expect for an electret filter around the MERV 8 to thirteen level with a low pressure level drib that was both affordable and easy to find.

A perfectly adept HVAC filter: Nordic Pure MERV 12

Nordic Pure's MERV 12 filter, a white corrugated fabric-looking material. — Photo: Michael Hession

Nordic Pure MERV 12

Nordic Pure'due south MERV 12 filters are non the only products that run into all our criteria, but they are perfectly skilful examples, and they're usually competitively priced and easy to find online. Nosotros similar that they're genuinely MERV-certified, because dissimilar the proprietary ratings used past some bigger-name brands, the MERV criteria are publicly available. Being rated MERV 12, the Nordic Pures will remove at least 35 pct of particles in the 0.3-to-1.0-micron range, which includes bacteria and smoke; at least 80 per centum of 1.0-to-iii.0-micron particles, which include fine grit and soot; and at least 90 per centum of larger pollen, dust, pet hair, and lint particles. Again, MERV stands for Minimum Efficiency Reporting Value, so this is the worst operation measured during third-party testing to the ASHRAE 52.2 standard. And again: the MERV test measures a single pass of polluted air through the filter. In your home, the air will continuously recirculate when your HVAC organisation is, leading to cumulatively greater filtration with each trip through the return registers.

Nordic Pure filters are more often than not sold online, and the MERV 12s typically retail for a much lower price than competitors—almost $40 for a six-pack of sixteen-by-25-by-i-inch filters, or most $vii each (with some competitors you lot'll pay about double that price for MERV eleven/12 or the equivalent). At the recommended three-month replacement bike, a Nordic Pure can salve you almost $xxx to $40 a year.

Nordic Pure reports the filter's force per unit area drop as 0.24 inch, which puts it a shade college than the similar, MERV 12–equivalent Filtrete 1500 at 0.22 inch. But almost people seem to have had no issues with the Nordic Pures straining their HVAC system—the six-pack has an overall score of 4.3 stars (out of five) beyond more 2,800 reviews at Amazon at this writing (we should annotation that the reviews once received an A rating from Fakespot; as of May 2019 that rating was downgraded to a C). The Nordic Pure MERV 12 filters are bachelor in many sizes, so you should be able to detect one that fits your render vent opening.

2 other filters that should do a fine task

A tester holding two 16 by 25 inch filters — Photo: Michael Hession

If y'all can't find Nordic Pure in your size, or if you prefer to purchase and pick up a new filter in a store immediately, Honeywell's FPR 9 filters and Filtrete'due south MPR 1500 filters are like, and they're widely available at retail. (Abode Depot stocks Honeywell; Lowe'south and Ace stock Filtrete). These filters perform on a similar level as the Nordic Pure MERV 12, they are well-reviewed by many owners, they come in a wide range of sizes, and the high likelihood that they're in stock at a nearby hardware store is a big advantage if you need one ASAP.

We don't love that neither Honeywell or Filtrete is MERV-certified, but their proprietary ratings are reportedly equivalent to MERV 11 or 12. We couldn't find pressure-drop information on the Honeywell, and so that's a possible concern. The Filtrete's pressure drib is 0.22 inch, fractionally lower than the Nordic Pure MERV 12'southward at 0.24 inch. Data Filtrete shared with us indicates the the 1500 removed 54 percent of 0.3-to-1-micron particles in its own tests, versus a minimum of 35 percent for the MERV 12-certified Nordic Pure. On larger particles, the two filters performed very similarly.

A major reason nosotros'd expect for Nordic Pure as an choice start comes downwards to toll: Both the Honeywell and Filtrete options normally cost more than than twice the toll of the Nordic Pure filters. As electret filters, all these models volition lose effectiveness every bit they capture particles, and should exist replaced at to the lowest degree every three months, per the manufacturers' recommendation. Simply homes with certain challenging weather condition—if y'all smoke, frequently apply candles or fireplaces, or have pets—will significantly reduce that lifespan.³

Owen too offered a simple way to judge if it'south time for a bandy: "If you can get to your filter easily, 1 simple affair yous can do is just become have a look. If you tin't see the filter media anymore, it's been in there too long. Change it!"

How often should I replace my filters during wildfire smoke events?

During a wildfire, you'll need to alter your filters more often than you would under normal air conditions, and there are a few indicators that can help yous know when information technology's time to supersede one.

We asked Kathleen Owen, the filtration expert we spoke with for this guide, for her advice. She replied in an email: "If I lived near the wildfires and didn't find the cost prohibitive, I'd probably change a 3-month filter every calendar month during the season. Or possibly after each major issue— say if a fire gets close enough to be a big deal (rather than simply you lot know nearly it from the news)."

Owen also noted that wildfire smoke is a circuitous mixture, incorporating both concrete smoke particles (which filters trap permanently) and water vapor and volatile organic compounds (gases), which are not trapped—and the latter of which create the smoky scent. "The wet particles or ones with gases adsorbed on them can be collected, so requite off the smelly stuff the adjacent time the fan comes on," she wrote. "So, one recommendation is that if folks feel similar the air breathes easier or smells OK with the HVAC on just are gagging in the outset infinitesimal or two the HVAC is on once more, changing the filter could assist."

There are also visual cues you tin can look for when judging whether to replace your furnace filter, Owen wrote. Clogging increases the pressure differential between the intake and outflow sides, and this can cause the filter'southward pleats to flatten out or the frame of the filter to buckle. Both are show that the smoky air is finding a path around the chock-full filter rather than through it, and that it's time to install a new one.

In addition to obvious steps like keeping windows and doors airtight, Owen too brash shutting off bathroom fans and range hoods, both of which vent directly to the outside and, as a result, describe an equal volume of smoky outdoor air in through window frames and other leaky spots.

Owen added that she'd too consider adding a portable air purifier with a VOC filter. All our purifier picks have them, and though in our tests against an extreme load of ethanol vapors nosotros found nigh of them ineffective, anecdotally we can say that they seem to perform well nether adequately heavy fume conditions. Both in guide author Tim Heffernan'south apartment and in our New York exam infinite, after running our acme picks for a few hours, in that location was little olfactory prove that hundreds of matches had been burned nearby.

Finally, Owen noted that the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) has begun working on edifice-filtration guidelines specific to wildfire conditions. We'll exist following upwards on this as it develops. For more on this topic, please run into our reporting on how to clean wildfire smoke from your home.