The right size diffuser depends on the floor area you want to scent: the Micro and Element smart diffusers cover up to 150sqm, and the Beacon and Pillar cover up to 300sqm. For a single smaller room, a reed diffuser, wood diffuser or candle is often all you need.
Here's how to work out your room size and which kirri diffuser fits it.
Step 1: measure the space
Multiply the length of the room by its width. A living room that is 5m by 4m is 20sqm. An open-plan kitchen, dining and living area that is 10m by 8m is 80sqm.
If rooms open onto each other with no doors, measure them together as one space. Scent moves through open doorways, so the whole connected area counts.
Step 2: match the area to a diffuser
A single smaller room
- Reed diffuser: suits bedrooms, bathrooms, entries and smaller living rooms. Add or remove reeds to adjust the strength. Shop the 200ml reed diffusers.
- Wood diffuser: solid beech that soaks up a 100ml traditional refill and releases it slowly. No power, no flame. See the wood diffuser.
- Candles and room spray: good for scenting one room when you want it, rather than all day.
Up to 150sqm
- Micro Diffuser: a compact metal smart diffuser for desks, bedside tables and living areas. Takes 15ml Micro Oil. See the Micro Diffuser.
- Element Diffuser: a ceramic smart diffuser for bedrooms, studies and open-plan areas. Rechargeable, and can run plugged in. Takes 15ml Micro Oil. See the Element Diffuser.
Up to 300sqm
- Beacon Diffuser: a metal smart diffuser built for open-plan living, large homes and high ceilings. Mains powered, takes 30ml Macro Oil or 100ml Aura Oil. See the Beacon Diffuser.
- Pillar Diffuser: floor-standing, for large living areas where you want the diffuser to be a feature. See the Pillar Diffuser.
Step 3: think about how the room is used
- Bedrooms: choose a reed diffuser, the Micro or the Element. The Beacon and Pillar have a low operating hum, so they're better suited to living areas than quiet rooms.
- High ceilings and airflow: air conditioning, ceiling fans and open windows spread scent thinner. Size up, or choose a stronger scent.
- Several separate rooms: one large diffuser won't push scent through closed doors. Two smaller diffusers in separate rooms often work better than one big one.
- Whole home: a common set-up is a Beacon in the main living area plus reed diffusers in bedrooms and bathrooms.
For a side-by-side comparison of our two main smart diffusers, read best diffuser for a large house or open-plan living.
Other types of diffuser, briefly
- Ultrasonic: mixes a few drops of oil with water and releases a visible mist. Needs refilling and cleaning each session. See waterless vs ultrasonic
- Heat diffusers and oil burners: warm the oil so the scent rises. Best for one smaller room, and never left unattended
- Passive: reed, wood and car diffusers need no power at all, for a softer, constant scent
Before you buy: a quick checklist
- Noise: waterless diffusers use a small air pump with a soft hum during each burst. The Element is rated at 36 dB. See how loud is a smart diffuser
- Upkeep: no tank on a kirri smart diffuser, so you swap the bottle and wipe the outside
- Power: the Element is rechargeable and runs plugged in; the Beacon and Pillar plug in at the wall
- Warranty: kirri smart diffusers come with a 12-month warranty
How long the oil lasts
- Element with 15ml oil: about 1 to 3 months.
- Beacon or Pillar with 30ml oil: about 2 to 6 months. With 100ml Aura Oil, about 6 to 12 months.
- 200ml reed diffuser: about 1 to 6 months, depending on reeds and room temperature.
These are typical ranges, not guarantees. App settings, schedules and the season all play a part.
Which oil fits which diffuser
Smart diffusers take pure fragrance oil. The Micro and Element take 15ml Micro Oil. The Beacon and Pillar take 30ml Macro Oil or 100ml Aura Oil. Reed, wood and car diffusers use traditional refills instead, and those should never go into a smart diffuser. Our oil compatibility guide has the full list.
Frequently asked questions
What size diffuser do I need for an open-plan living area?
Measure the connected space. Up to 150sqm, a Micro or Element works well. Above that, or with high ceilings, choose a Beacon or Pillar.
Can one diffuser scent a whole house?
A Beacon can cover up to 300sqm of open space, but scent doesn't travel well through closed doors. Most homes get the best result from one larger diffuser in the living area and smaller ones in other rooms.
What's the best diffuser for a bedroom?
A reed diffuser, the Micro or the Element. They suit smaller rooms and run quietly.
Found your size? Shop smart diffusers or browse reed diffusers.
more guides: all diffuser guides