Replacement filters for kitchen exhaust pollution control units

OEM fit. Better media.

Every stage of your PCU, from the grease mesh to the caustic-blend carbon. Built to your unit's exact dimensions, with media that matches the original spec or beats it.

Match my OEM part See the filter lineup

CROSS-SECTION · AIRFLOW →

GreaseSmokeOdor

Exact fit

Built to the actual dimensions of your OEM filter, not a close nominal size. A filter that fits loose lets grease bypass straight into the next stage.

Same media or better

We match the original efficiency rating at minimum. Where a higher grade costs you no extra airflow, we offer the step up.

Every stage, one order

Mesh, pleats, bags, HEPA and carbon from one supplier, so a full change-out arrives together.

Replacement filters for units from

CaptiveAire
Halton
Greenheck
Accurex
Trion
SmogHog
Air Quality Engineering (AQE)
and others

The lineup, in airflow order

Seven filters, each with one job

A PCU works as a chain. Each stage takes out what it is best at and protects the stage behind it. When one stage is skipped or overdue, the next one loads up fast and the whole unit costs more to run.

Not every unit takes every filter

Your unit uses some of these stages, not all seven

Each PCU model is built around its own set of filters. Most systems we see are CaptiveAire, which typically run three stages: SOLO stainless baffle filters as the first pass, then a MERV media filter, then an odor stage. CaptiveAire's standard odor filter is 100% carbon, with caustic and permanganate blends offered as options.

Typical CaptiveAire PCU

SOLO first pass→MERV→Carbon or Caustic Blend

ESP unit

Mesh safety filter before→ESP cells washed daily→Mesh safety filter after→Carbon

In an ESP unit, the electrostatic cells take the place of the MERV stage, with a mesh safety filter on each side. The first one catches heavy grease and protects the cells. The second one catches any grease that blows off the cells before it reaches the carbon. The carbon handles odor. On most units the cells are washed daily, and we sell the detergent.

Not sure what yours takes? Send us the model or the part number on the old filter and we'll list the exact set.

Stage 1

Mesh

GREASE

Layers of knitted aluminum or stainless steel mesh. Grease droplets hit the wire, cool, and drain out. It is the first line of defense and the only washable stage.

A clean mesh stage is the cheapest way to make every filter behind it last longer. On CaptiveAire units, this first pass is a SOLO stainless baffle filter instead.

CATCHES: Grease droplets, roughly 10 µm and up
DEPTHS: 1″, 2″
FRAME: Galvanized, aluminum or stainless
SERVICE: Wash on schedule, replace when crushed or torn

Stage 2

Z-pleat

GREASE

Media folded in a zigzag inside a rigid frame. The pleats pack a lot of surface into a thin panel, so it holds a heavy grease load at low resistance.

Catches the grease mist that slips through the mesh before it reaches finer filters.

RATING: Typically MERV 8
DEPTHS: 2″, 4″
MEDIA: Synthetic, grease-tolerant
SERVICE: Disposable

Stage 2–3

MERV pleated

SMOKE

Extended-surface pleated filters rated to ASHRAE 52.2. Higher MERV means better capture of fine particles. We match your OEM's rating and can step it up when airflow allows.

Our 4″ MERV 15 drops straight into CaptiveAire-style PCUs, with an all-metal frame, a high grease-loading media pack and a low 0.23″ starting resistance.

RATING: MERV 8, 13, 14, 15
MERV 13: ≥ 50% of 0.3–1 µm, ≥ 85% of 1–3 µm
DEPTHS: 2″, 4″, 6″, 12″ rigid
CHANGE: Every 3 months

Stage 3

Bag

SMOKE

Multi-pocket bags that inflate in the airstream. All that media area means a long service life and a slow pressure rise, which is why many units run bags ahead of the HEPA.

RATING: MERV 13–15
POCKETS: 6 or 8
POCKET DEPTH: 15″, 22″, 30″
SERVICE: Disposable

Stage 4

HEPA

SMOKE

The stage that takes out visible smoke haze. HEPA media removes 99.97% of particles at 0.3 µm, the size that is hardest to catch. Gasketed frames seal against the track so nothing bypasses.

EFFICIENCY: 99.97% at 0.3 µm
STYLE: Box or mini-pleat
DEPTHS: 6″, 12″
SERVICE: Disposable, never wash

Stage 5

Carbon

ODOR

Activated carbon has a huge internal surface. Odor molecules stick to it as air passes through, a process called adsorption. It handles the broad mix of cooking odors well.

Available in Standard and Heavy Duty. What's the difference?

REMOVES: Odor VOCs, smoke organics
GRADES: Standard, Heavy Duty
FORMAT: Trays, cassettes, bonded panels
CHANGE: Standard every 3 months, Heavy Duty every 6 months

Stage 5

Caustic blend

ODOR

Standard carbon blended with carbon impregnated with potassium hydroxide, a caustic. The caustic reacts with acidic odor compounds and turns them into salts that stay locked in the media. How it works

REMOVES: Fatty acids, H₂S, sulfur compounds, plus everything plain carbon catches
FORMAT: Trays, cassettes
BEST FOR: Charbroil, frying, wood-fired
SERVICE: Replace or refill media

Electrostatic precipitator units

Most ESP units wash their cells daily. We sell the detergent.

Some PCUs use an electrostatic precipitator in place of a MERV filter, typically with a mesh safety filter before and after the cells and carbon behind them. Instead of trapping particles in a filter, it puts an electric charge on them and pulls them onto metal collector plates. The plates don't get replaced. They get washed.

Where the cells sit in the unit

Mesh safety filter before→ESP cells→Mesh safety filter after→Carbon

ChargeAn ionizer section gives each grease and smoke particle an electric charge.

CollectCharged particles are pulled onto oppositely charged aluminum plates and stick there.

WashOn units with an automatic wash, a cycle runs daily after service, spraying hot water and detergent over the cells and rinsing the grease to drain. The cells also get pulled and hand-cleaned on the unit maker's schedule.

Grease left on the plates cuts how much the cells can capture. Run the wash cycle your unit's maker specifies, and check which detergent type its manual calls for. Some makers say a detergent other than their own can void the warranty, so check yours before you switch.

ESP & PCU detergent

Colloidal hood wash detergent

A colloidal cleaner breaks grease into tiny droplets and keeps them suspended in the wash water. The grease rinses off the collector cells and out the drain instead of settling back on the plates.

For ESP wash systems and water-wash hoods.

Order detergent

Odor control

Why the caustic blend matters

Cooking smell is a mix of hundreds of compounds. Plain activated carbon handles most of them well, including the fatty acids from fryer oil and grilled fat. Its weak spots are acid gases, like hydrogen sulfide and the sulfur dioxide from wood and charcoal fires, and light aldehydes like formaldehyde. A caustic blend adds a chemical reaction for the acid gases.

Plain carbon · adsorption

Molecules stick to the surface

Odor molecules cling to the carbon's pores by weak physical attraction. It works on a wide range of compounds, but a weakly held molecule can be pushed off by heavier ones, or by heat and humidity in the airstream.

odor molecule + carbon pore → held (reversible)

Caustic blend · chemisorption

Acids are neutralized in place

The potassium hydroxide in the impregnated carbon reacts with acid gases such as hydrogen sulfide and sulfur dioxide, and with short-chain acids. The product is a salt bound inside the media, so it cannot be released again. The caustic also slowly reacts with carbon dioxide in the air, so caustic media loses capacity with age even before it starts to smell.

R–COOH + KOH → R–COOK + H₂O

Odor family	Where it comes from	Plain carbon	Caustic blend
Volatile fatty acids butyric, hexanoic acid	Fryer oil breakdown, charbroiled meat fat	Strong	Strong, also neutralized
Sulfur compounds H₂S, mercaptans	Onions, garlic, eggs, brassicas	Mixed: good on mercaptans, varies on H₂S	Strong
Acid gases SO₂	Wood and charcoal fires	Weak	Strong
Smoke organics heavier VOCs	Charbroiling, smoking, searing	Strong	Strong (carbon base)
Acrolein heavier aldehyde	Oil past its smoke point	Good	Good (carbon base)
Formaldehyde light aldehyde	Combustion, heated oils	Weak	Weak

Carbon only performs when the grease stages ahead of it are maintained. Grease that reaches the carbon coats the pores and ends its life early, whichever blend you run.

Standard carbon

3 months between changes

A lighter carbon load sized for everyday cooking. It does the job at a lower price per change.

Less carbon in each tray, so less capacity to fill up
Good fit for moderate-volume kitchens and lighter menus

Heavy Duty carbon

6 months between changes

More carbon packed into the same footprint. The deeper bed holds roughly twice the odor before it's full, and air spends longer in contact with the carbon, so capture stays strong for longer.

About twice the service life, so half as many change-outs
Built for high volume, charbroiling, frying and wood-fired kitchens

Running Heavy Duty often costs less per year: one change instead of two, and one service visit instead of two.

UV odor stage

Some units add UV lamps ahead of the carbon

Some PCUs offer UV lamps in the odor stage. Halton's PolluStop, for example, offers a UV/carbon module on units of 4,000 CFM and up. The UV-C lamps break down cooking vapors by oxidation, and carbon panels after them adsorb the odor compounds that remain. UV doesn't replace the carbon.

Typical UV odor stage

Grease & smoke filters→UV-C lamps oxidize vapors→Carbon remaining odor

The carbon

Still changed on schedule

Behind UV lamps the carbon catches the odor compounds the lamps didn't finish. Keep it on the same Standard or Heavy Duty change schedule as any other carbon stage.

The lamps

Only as good as the filters ahead

Grease that gets past the filters films over the lamps and cuts their output. Keep the grease and smoke stages changed on time, and replace the lamps on the unit maker's schedule.

Never open a UV section with the lamps on. UV-C light is harmful to eyes and skin. Shut the unit down before servicing filters near the lamps.

Sizes

Nominal size vs. the size you measure

Filters are sold by nominal size, the rounded number on the label. The real filter is smaller so it slides into the track. A 24 × 24 × 2 usually measures about 23⅜ × 23⅜ × 1¾. Measure your old filter and we'll tell you what it is.

Size finder

Width (in) Height (in) Depth (in)

24 × 24 × 2Nominal size. Fractions like 23 3/8 work too.

Odd size, or a filter with a special frame? We build to your measurements. Include them in your quote.

Filter	Common face sizes	Depths
Mesh	16×25, 20×20, 20×25, 24×24	1″, 2″
Z-pleat	12×24, 16×20, 20×20, 20×24, 24×24	2″, 4″
MERV pleated	20×25 (CaptiveAire 4″), 24×24 (Greenheck 2″), 16×20, 12×24, 20×20	2″, 4″, 6″, 12″
Bag	12×24, 20×24, 24×24	15″, 22″, 30″ pockets
HEPA	12×24, 24×24	6″, 12″
Carbon / caustic	24×24 and 20×20 trays, 22×22 panels, 18×24 modules	1″–6″ bed, 12″ V-bank

Change-out

Change on schedule. Check the gauge in between.

Our recommended schedule is below. It keeps you ahead of the unit makers' own guidance, which runs from checking filters monthly to replacing odor media every 3–6 months. Set the change-outs on a calendar. Between visits, the pressure gauge on each stage tells you if a filter is loading up early, for example after a busy season or a missed mesh cleaning.

Filter	Change every	Changes per year
MERV	3 months	4
Standard carbon	3 months	4
Heavy Duty carbon	6 months	2

Gauge readings are in inches of water column. A filter that reaches its change point before its scheduled date is done early. Values shown are for the filters we supply, and your unit's label and manual come first.

Quote & OEM match

Send us your part or job number. We'll match it.

Tell us the unit
The job number from the nameplate if it's a CaptiveAire unit, the serial number, the manufacturer and model, or the part number printed on the old filter's frame. You don't need to know what filters are inside.
We match the spec
Exact dimensions and the same efficiency or better, stage by stage.
You get one quote
The full change-out set priced together.