Open-plan kitchen, living and dining areas are common in modern Australian homes — and they're one of the easiest spaces to under-size an air purifier for. A unit rated for a 30m² bedroom will struggle badly in an 80m² open-plan living area, no matter how good its filter is.
Why Sizing Matters More in Open-Plan Homes
An open-plan layout combines what used to be three separate rooms — kitchen, living, dining — into one continuous air volume, often with higher ceilings than a standard bedroom too. Cooking smoke, higher foot traffic, more soft furnishings and larger windows all add pollutant load, while the sheer volume of air means a purifier has more air to cycle through to reach the same clean-air result. Undersizing is the single most common mistake in this room type.
Calculating Your Actual Room Size
Measure length × width for the combined space, not just the "living room" portion — include the dining and kitchen area if they're not separated by walls or doors. Don't forget to account for ceiling height above the Australian standard of roughly 2.4m; a room with 3m+ ceilings (common in newer builds and renovated older homes) has meaningfully more air volume than the floor area alone suggests.
For open-plan spaces specifically, choose a purifier rated for at least 20–30% more than your measured floor area. High ceilings, constant air movement between zones, and cooking pollutants all add real-world load that a straight floor-area calculation understates. See our CADR ratings guide for the full sizing formula.
One Large Unit vs Multiple Smaller Units
There are two valid approaches for open-plan spaces, and the right one depends on layout:
- One large-capacity unit — works well when the space is fairly open with good air circulation and no major obstructions between zones. Simpler to manage, one filter to maintain.
- Two smaller units placed strategically — better when the space has distinct zones (e.g. a kitchen separated from living by an island bench, or an L-shaped layout). Placing one purifier near the kitchen and one near the living/dining seating area often clears the air faster than a single unit trying to reach both ends.
As a rule of thumb, if you can't see clearly from one end of the space to the other, or the layout has genuine corners and nooks, two moderate units usually outperform one large unit at a similar combined price.
What to Check Before Buying
- CADR high enough for the full combined area, not just the living room portion
- A genuine activated carbon layer — essential in open-plan homes given proximity to cooking odours
- Enough tank/filter capacity for continuous operation across a larger space without frequent maintenance
- Noise level at the fan speed you'll realistically run it at — a large-capacity unit often needs a higher speed to reach its rated CADR, so check the dB rating at that speed, not just the lowest setting
Placement in Open-Plan Spaces
Placement affects a large open room far more than a small enclosed one, since there's more air to move and more paths for it to take:
- Position centrally where possible, rather than against one wall of the whole space
- If splitting between two units, place one nearer the kitchen (cooking odours, grease particles) and one nearer the seating area
- Avoid placing directly under air conditioning vents, which can disrupt the purifier's own airflow pattern
- Keep clear space on at least two sides for intake and outlet
Conclusion
Open-plan living areas need a meaningfully larger CADR than the equivalent floor area of a closed room, because of higher ceilings, more air movement and added pollutant sources like cooking. When in doubt, round your room size up rather than down, and consider two moderate units over one large one if your space has distinct zones. Getting sizing right here matters more than almost any other room type in the house.