Plan office air purification room by room. For each space, calculate the volume, pick a clean-air target (5 air changes per hour is a good default, more for dense meeting rooms), check that the unit can deliver it at a noise level suited to the room, and assign someone to maintain it. Keep ventilation separate: purifiers reduce particles but do nothing for CO₂, which is the best everyday indicator of whether a room gets enough outdoor air.
Start with an inventory of rooms
An office is not one room. A reception, an open-plan floor, a 12-person meeting room and a phone booth have very different volumes, occupancy and noise expectations. List each space with its dimensions, typical and peak occupancy, how long people stay, and what ventilation it already has.
| Space type | Occupancy pattern | Typical priorities | Planning notes |
|---|---|---|---|
| Meeting rooms | Dense, 30–120 min sessions | High clean air per person, low noise | Size for peak occupancy; CO₂ monitor strongly recommended |
| Open-plan areas | Moderate density, all day | Even distribution, low draught | Several units or ceiling-integrated units spread across zones |
| Private offices | 1–2 people, all day | Quiet operation | Small unit at low speed usually sufficient |
| Reception / waiting | Changing visitors | Robust operation, low maintenance | Door openings bring in outdoor air and particles |
| Kitchenettes / print rooms | Short visits, local sources | Odor and particle control near source | Carbon stage helps with odors; local exhaust is better where available |
Set a clean air target for each room
Two complementary ways to set targets are useful in offices:
- Air changes per hour. Room volume × target clean ACH gives the required clean air delivery rate (CADR). The U.S. CDC's ventilation guidance suggests aiming for 5 or more air changes per hour of clean air. See how to size an air purifier.
- Clean air per person. ASHRAE Standard 241 (2023) expresses targets as equivalent clean airflow per occupant, combining outdoor air and filtration. In dense rooms, per-person targets often call for more clean air than a volume-based target would.
In practice, calculate both and plan for the higher value.
Worked example: a 10-person meeting room
Volume-based target. 84 m³ × 5 ACH = 420 m³/h of clean air.
Occupancy check. 420 m³/h ÷ 10 people = 42 m³/h per person from filtration alone, before counting outdoor air from ventilation. If your organisation adopts a higher per-person target for dense rooms, increase the purifier capacity accordingly.
Noise check. Meeting rooms are often designed for background noise in the mid-30s dB(A). Choose one or two units that together deliver about 420 m³/h at or below that level — typically meaning larger units running at moderate speed.
Placement. Keep outlets away from blowing directly onto seated people; ceiling-integrated or high-mounted units help here.
Monitoring. Install a CO₂ sensor. If readings regularly climb well above about 1,000 ppm during meetings, the room needs more outdoor air, whatever the purifier does.
Noise targets matter more in offices than anywhere else
A purifier that disturbs a presentation or a phone call gets switched off. Office acoustic design commonly works with background noise levels in the mid-30s dB(A) for meeting rooms and private offices and somewhat higher in open-plan areas. A few practical rules:
- Compare units by clean air delivered at an acceptable sound level, not by maximum CADR.
- Oversized units running slowly are usually quieter than small units running fast — fan noise rises steeply with speed. See air purifier noise explained.
- Avoid automatic modes that ramp up audibly during meetings; use scheduled or manual settings in sensitive rooms.
- Check for tonal hum and vibration, which are more annoying than a steady airflow sound.
Draught and comfort
People notice air movement on the neck and ankles. Air velocities above roughly 0.15–0.2 m/s at seated positions can be perceived as draught, especially with cooler air. Point outlets along walls or the ceiling rather than at desks, and use more units at lower speed rather than one powerful jet. Ceiling-integrated units that discharge air horizontally along the ceiling can use the ceiling surface to spread air before it reaches occupants.
Keep ventilation and purification separate in your plan
| Issue | Air purifier helps? | What actually controls it |
|---|---|---|
| Fine particles (PM2.5), outdoor smoke ingress | Yes | Filtration (purifiers, higher-grade HVAC filters), building tightness |
| Odors from kitchenettes, printers | Partly (carbon stage) | Local exhaust, source control, carbon filtration |
| Stuffiness, high CO₂ | No | Outdoor air ventilation |
| Humidity problems | No | HVAC humidity control, source control |
For the underlying pollutant differences, see PM2.5, VOCs and CO₂ explained.
Placement in open-plan offices
- Distribute capacity across zones instead of placing one large unit at one end of the floor.
- Keep intakes clear of partitions, filing cabinets and plants.
- Avoid positions directly under supply diffusers, where the unit would mainly re-filter freshly supplied air.
- Consider ceiling-integrated units where floor space is valuable and where cable management for floor units would be awkward.
Maintenance: plan it before you buy
Office purifiers often fail not because of poor products but because nobody owns them. Before installation:
- Assign responsibility to facilities management or a service contractor.
- Label each unit with an ID and its room.
- Keep a simple log per unit: install date, filter changes, pre-filter cleaning, issues.
- Stock at least one spare set of filters per model.
- Budget annual filter costs alongside the purchase price.
Our maintenance guide includes a schedule you can adapt.
Communicating with staff
Explain what the purifiers do and do not do. Staff should know that purifiers complement ventilation, that opening a window on a high-pollution day may undo their effect, and whom to contact if a unit is noisy or faulty. Clear information prevents units being unplugged or blocked with coats and boxes.
Key takeaways
- Plan room by room: volume, occupancy, noise target, maintenance owner.
- Calculate clean air by volume (≈5 ACH) and per person, and plan for the higher figure.
- Choose units by clean air delivered at an acceptable noise level; avoid draughts at desks.
- Purifiers do not reduce CO₂ — keep ventilation and CO₂ monitoring in the plan.
Frequently asked questions
Does an air purifier replace office ventilation?
No. Purifiers recirculate and filter indoor air; they do not supply outdoor air or remove CO₂. Offices need mechanical or natural ventilation that meets local building regulations, with purification added to increase clean air for particles.
How loud can an office air purifier be?
It depends on the room. Meeting rooms and private offices are often designed for background levels in the mid-30s dB(A), open-plan areas somewhat higher. Choose units that deliver the required clean air at a speed that stays within the room's normal background noise.
Who should maintain office air purifiers?
Assign them to facilities management or an external service provider, with a written schedule, a stock of spare filters and a simple log per unit. Unmaintained purifiers lose airflow and can become a source of complaints.
Sources and further reading
- ASHRAE Standard 241-2023 — Control of Infectious Aerosols (equivalent clean airflow concept)
- U.S. Centers for Disease Control and Prevention — ventilation guidance for buildings and homes (2023 update recommending 5 or more air changes per hour of clean air)
- U.S. EPA — Guide to Air Cleaners in the Home
- World Health Organization — WHO global air quality guidelines (2021)