If you’ve heard contractors, restoration pros, or HVAC techs talk about air scrubbers and wondered “what does an air scrubber do?”, here’s the plain‑English answer: an air scrubber is a high‑powered filtration unit that pulls dirty air in, traps fine particles (like dust, smoke, and spores) with HEPA filtration, and pushes cleaner air back out. Many models also let you duct the exhaust outside to create negative pressure so contaminants don’t spread to the rest of the building. Think of it as a heavy‑duty, job‑site‑ready air purifier with more airflow, more filter media, and more ways to set it up.
On TheDryAir’s HEPA Air Scrubbers & Negative Air Machines page, you’ll see typical airflow from ~270 to 2,000 CFM and multi‑stage filters (pre‑filter + HEPA, often with optional carbon/UV). That higher airflow is what makes air scrubbers so effective during dusty projects, flood cleanup, or smoke events.
Quick definition (and two common versions)
- Portable air scrubber / negative air machine (most common): A standalone box with handles or wheels. Pulls air through pre‑filter → HEPA (99.97% @ 0.3 µm) → optional carbon for odors; some units add UV. You can recirculate the cleaned air or duct the exhaust outdoors for negative pressure during containment.
- In‑duct “air scrubber” (HVAC add‑on): A device installed in supply/return ductwork that treats air as it moves through your system. Consumer and contractor sites often use “air scrubber” for these, which can include mechanical filtration and/or electronic/UV technologies. Our focus here is the portable HEPA style used for projects and remediation.
How an air scrubber works (step‑by‑step)
- Intake: A powerful blower draws room air into the cabinet. Many units move 500–2,000 CFM—far more than a typical living‑room purifier.
- Pre‑filter: Catches hair, drywall dust, and larger debris so the HEPA stays efficient longer.
- HEPA filter: The star of the show. HEPA is a pleated mechanical filter that removes ≥99.97% of particles 0.3 microns in size—the toughest size to capture; larger and smaller particles are removed at similar or higher rates.
- Optional carbon stage: Adsorbs some odors/VOCs (capacity depends on how much carbon is used).
- Optional UV/ion features: Some models include UV‑C inside the cabinet. If you choose anything with ionization or other electronic tech, ensure it meets CARB’s indoor air cleaner rules and does not produce unhealthy ozone.
- Exhaust (two ways):
- Recirculation (most home jobs): discharge cleaned air back into the room.
- Negative air setup (remodels/mold/fire): duct the exhaust outdoors to keep dust and spores from escaping the work zone.
Air scrubber benefits (why pros use them)
- Captures fine particles: drywall/plaster dust, sanding debris, sawdust, pollen, mold fragments, and smoke PM2.5—the small stuff that irritates lungs the most.
- Controls spread: with plastic containment and negative pressure, you limit cross‑contamination to occupied areas during mold remediation or demo.
- Cuts odors: add activated carbon to reduce paint, adhesive, or smoke odors (note: gases require adequate carbon; filtration alone won’t remove all VOCs).
- Flexible & fast: higher CFM means more air changes per hour (ACH); that translates to faster clean‑up of airborne particles versus small consumer purifiers. NIOSH’s general target of 5+ ACH of clean air is a helpful benchmark for cleaner air in occupied spaces.
Where air scrubbers are used (with real examples)
- Remodeling & construction dust control: During demo, drywall sanding, or tile removal, HEPA air scrubbers cut airborne dust and help workers meet best practices alongside OSHA silica controls. (Use dust suppression, capture at source, and HEPA filtration together.)
- Mold remediation & water damage: EPA guidance for schools/commercial buildings recommends HEPA filtration and negative pressure containment for larger jobs to protect occupants and prevent spread. Portable HEPA units are standard equipment.
- Wildfire smoke & structure fire cleanup: Portable air cleaners (HEPA) reduce smoke particles indoors; EPA advises selecting non‑ozone‑emitting units sized for the room and running them on higher speeds during smoke events.
- Finishing, painting, salons, print shops: HEPA + carbon helps manage overspray and odors—still supplement with source control/ventilation. (TheDryAir’s category page shows use‑case tiles for painting, renovations, salons, and more.)
- Healthcare & isolation areas (temporary): For non‑clinical spaces, portable HEPA devices can add “equivalent ACH” and, with proper ducting, support negative pressure concepts. Hospital isolation room standards are different and much higher; follow local codes and facility guidelines.
Air scrubber vs. air purifier: what’s the difference?
Both filter air, but they’re optimized for different jobs:
- Air purifiers (consumer portable units) are sized for single rooms and use CADR ratings; great for bedrooms/living rooms and day‑to‑day allergies. They recirculate room air.
- Air scrubbers are industrial‑grade with higher CFM, larger filters, daisy‑chain power options, and duct ports so you can create negative pressure or vent outdoors. They shine during renovation, remediation, and cleanup—or when you need to move a lot of air, fast.
Bottom line: For everyday living spaces, a room air purifier may be enough. For projects (dust, mold, smoke, odors) or to protect adjacent areas, choose an air scrubber. EPA notes that filtration supplements—not replaces—source control and ventilation.
Sizing an air scrubber (easy math)
To pick the right size, think in air changes per hour (ACH)—how many times the unit can cycle the room’s air each hour.
Formula:
ACH = (CFM × 60) ÷ Room Volume (length × width × height in feet)
Target: A practical rule for cleaner indoor air is ~5 ACH of clean air, combining ventilation and filtration (NIOSH). For sensitive tasks or tougher conditions, go higher.
Example: A 20 ft × 15 ft room with 9 ft ceilings = 2,700 cu ft.
To reach 5 ACH: required airflow ≈ (2,700 × 5) ÷ 60 = 225 CFM.
Even a compact scrubber (270–550 CFM) can handle that; bigger rooms, heavy dust, or smoke may justify 600–2,000 CFM. (See TheDryAir’s category for options across that range.)
Pro tip: Higher ACH clears particles faster. CDC’s table shows that at 6 ACH, it takes roughly 46 minutes to remove 99% of airborne contaminants (and less time as ACH rises).
Set‑up tips that amplify results
- Place it smart: Centered or slightly off‑center with clear intake/exhaust; avoid blocking flow with curtains or plastic.
- Seal the room if you’re containing dust/mold: Poly sheeting + sealed vents + negative pressure (exhaust outside). Check that plastic billows inward; if it flutters outward, you’ve lost containment.
- Run it long enough: More runtime + higher fan speed = more filtration; leave it on through dusty phases and for a period after you finish.
- Use carbon if odors matter: Smoke/paint/adhesives benefit from a real carbon stage (thicker = better capacity).
- Replace filters on schedule: Dirty filters reduce CFM and efficiency; follow manufacturer guidance.
Safety notes (read this if you’ll be in the room)
- Mechanical HEPA = safe for occupied spaces; just loud at higher speeds. Avoid devices that produce ozone. California’s CARB requires air cleaners sold in the state to meet strict ozone limits; look for CARB‑certified devices.
- During mold remediation, keep the work zone isolated and under negative pressure; limit occupant access and wear appropriate PPE when disturbing materials.
- Wildfire smoke: Choose non‑ozone units and run them continuously on higher speeds in your main living area or a designated clean room.
What do air scrubbers do on TheDryAir?
On the Air Scrubbers & Negative Air Machines collection, you’ll find portable units with multi‑stage filtration and CFM options to match bedrooms, basements, renovation zones, and open‑plan areas. Many include daisy‑chain outlets, hour meters, and optional UV or carbon modules—useful for restoration, remodeling, painting, salons, and post‑fire cleanup.
Frequently Asked Questions
Do air scrubbers really work?
Yes—HEPA filtration is a proven mechanical method that removes ≥99.97% of 0.3 µm particles, and portable air cleaners are shown to reduce fine particulate levels indoors (which helps with dust and smoke). They don’t fix moisture problems or remove every gas without carbon, but they meaningfully lower particle exposure when sized and run correctly.
Is it safe to be in a room with an air scrubber?
With mechanical HEPA units, yes. Avoid ozone‑generating devices marketed as “air cleaners”—ozone is a lung irritant. Look for CARB‑certified products and keep cords/hoses tidy to avoid trip hazards.
Which is better, an air purifier or an air scrubber?
Different tools. A room air purifier is great for everyday living spaces; an air scrubber moves more air, uses larger filters, and can be ducted for negative pressure—better for renovations, remediation, or smoke cleanup. EPA’s consumer guide supports using portable air cleaners for particles and activated carbon for odors/VOCs.
Does an air scrubber remove smoke?
Yes—HEPA significantly reduces smoke particles (PM2.5). For odor compounds, use activated carbon. EPA recommends non‑ozone portable air cleaners during wildfire smoke and running them as often as possible on higher speeds.
How long should you run an air scrubber?
Run it continuously during dusty work or smoky periods and after the source stops to allow enough ACH to clear the air. More runtime and higher speeds filter more air. CDC/NIOSH suggests 5+ ACH of clean air as a practical goal; higher ACH clears faster.
