Sizing an air purifier for an open-plan condo living and dining area

Key takeaways

• Treat an open-plan living and dining area as one room for sizing purposes, not two separate zones.
• Required CADR equals floor area multiplied by ceiling height multiplied by a target air changes per hour of roughly 3 to 4 for a home.
• A partial wall or half-height divider slows air exchange but rarely blocks it enough to justify sizing the space as two rooms.
• Central, open placement works better in an open-plan layout than a corner near either the sofa or the dining table alone.
• Confirm your combined floor area figure against a product's stated coverage using the calculator before ordering.

Why an Open-Plan Layout Should Be Sized as One Combined Space

Many Singapore condos are built with the living and dining area as a single continuous space, often with the kitchen opening onto it as well. Because there is no wall separating these zones, air circulated by the aircon and by normal movement through the home mixes freely between them. Sizing a purifier for just the living room portion, and hoping it also covers the dining table, usually leaves the dining end under-served, especially during meals when cooking odours and steam are also moving through the same open air.

The practical approach is to measure the full open-plan footprint as a single room, then size the purifier to that combined area rather than to whichever section feels like the main living space. This avoids the common mistake of buying a unit that looks adequate on paper for one zone but is quietly undersized for the space it actually needs to clean. It also avoids a second, less obvious mistake: buying two smaller units for each zone when one correctly sized unit for the whole footprint would have covered both more evenly.

Applying the CADR Formula to the Full Living and Dining Footprint

AIRE's sizing method is straightforward: required clean-air delivery rate, or CADR, in cubic metres per hour equals floor area in square metres multiplied by ceiling height in metres multiplied by a target air changes per hour. For a home, that target ACH is generally 3 to 4.

Measure the living and dining area together as one continuous footprint, including any part of the space the kitchen opens directly into, and use that combined square metre figure in the formula. A larger combined area will usually call for the Classic 400S rather than a compact home unit, since open-plan condo living and dining spaces often exceed what a single small-room purifier is designed to cover. Check the exact figure with the size calculator once you have measured the space.

When a Partial Wall or Half-Height Divider Changes the Calculation

Some condo layouts include a partial wall, a half-height planter divider, or a change in flooring material marking where the dining area starts. None of these fully separate the airflow the way a floor-to-ceiling wall and door would, so the space should still generally be sized as one combined room rather than split in two.

The exception is a genuine full-height wall with a door that stays closed, which does meaningfully slow air exchange between rooms and justifies separate sizing. If your layout only has a partial divider, size for the whole open footprint and place the unit where it has a clear path to both zones, rather than assuming the divider does more than it actually does.

Placement in an Open-Plan Space Without Blocking Sightlines

Corners are usually the weakest placement for any purifier, since walls on two sides restrict how air is drawn in and pushed back out. In an open-plan living and dining area, a more central position, such as against a wall roughly midway between the seating area and the dining table, gives the unit a clearer path to circulate air across the whole combined space.

Condo owners are often reluctant to place a bulky unit where it interrupts sightlines through an open floor plan. A compact model positioned along a side wall, rather than in the middle of the floor, usually balances coverage with keeping the space feeling open. Avoid placing the unit directly behind furniture or curtains, since that blocks intake and reduces how much air it can actually treat.

Confirming Sizing With the Calculator

Once you have the combined floor area of your living and dining space, run it through the calculator with your actual ceiling height and a target ACH of 3 to 4 rather than relying on a rough estimate. Condo ceilings vary more than HDB flats do, particularly in developments with higher void spaces near the living area, and a higher ceiling increases the required CADR even if the floor footprint looks similar to a neighbour's unit one floor down.

If the resulting figure sits close to the boundary between two AIRE models, it is worth requesting a free room-by-room Air Report rather than guessing, particularly if your layout includes an open kitchen adding further volume to the space the purifier needs to cover. A short survey also settles any doubt about whether a partial divider in your specific layout should change the calculation, rather than relying on a general rule that may not quite fit your unit.

Next step

Measure your combined living and dining footprint and run it through the air purifier size calculator to find the right coverage before you buy.

Frequently asked

Should an open-plan living and dining area be sized as one space?

Yes. Air circulates freely across an unwalled living and dining area, so measuring the combined floor area and sizing to that total gives a more accurate result than treating either zone on its own.

Does a partial divider change the sizing calculation?

A half-height wall or a flooring change slows air exchange slightly but does not block it enough to justify separate sizing. Only a full-height wall with a closable door meaningfully changes the calculation.

Where should a unit be placed in an open-plan layout?

A central position, such as a side wall roughly midway between the seating and dining areas, generally works better than a corner, since corners restrict airflow on two sides and limit how much of the combined space the unit can reach.

Related reading

• The Best Air Purifier in Singapore: An Honest Market Guide