Fragrancing a house on two floors: how many devices?
Fragrancing a house on two floors almost always calls for two devices, one per level: the coverage figures given for a diffuser describe an enclosed room, never a home spread across several floors. A PURRA X300S covers the 100 m² of the living level, while a portable model rated for 10 m² is enough for a bedroom upstairs.
Cold nebulisation is a process that projects fragrance as dry micro-droplets, with no added water and no heating element. The mist leaves the top of the device, spreads through the volume where it is released, then settles. That mechanism, not the power of the device, decides how many diffusers a house with an upper floor needs. Our page on home fragrance diffusers presents the range by coverage.
Key points:
- The stated coverages of 10, 100 and 180 m² are enclosed-room figures: none of them describes a home spread across two levels.
- The practical rule is one device per level, sized on the surface of that level and not on the surface of the whole house.
- Downstairs, a device rated for 100 m² for the living area; upstairs, a portable model rated for 10 m² for a bedroom.
- A 100 ml scent refill lasts 625 operating hours on the gentle setting, around 78 days at 8 hours of diffusion per day; a 10 ml bottle lasts 333 hours, around six weeks on the same basis.
- Free delivery from 49 € to France, Switzerland and Monaco, dispatch within 24 to 48 hours, returns accepted within 14 days, two-year legal guarantee of conformity.
Why a single diffuser does not cover two levels
A single diffuser does not cover two levels because the stated coverages of 10, 100 and 180 m² all describe the volume of an enclosed room. They describe reach within one space, never the way a home is distributed across several floors. A stairwell is not a distribution duct.
The mechanism explains the rest. The mist is intermittent by design: on the gentlest setting the device releases 15 seconds of mist then pauses for about three minutes, and on the strongest setting 15 seconds then one minute. The pause is what produces the result, since continuous diffusion eventually stops being perceived. The fragrance therefore settles in the immediate volume instead of being carried further by any airflow.
Olfactory adaptation adds to this: whoever lives in the house stops perceiving its own signature, while a visitor receives it at once on walking in. In a house with an upper floor this sustains a stubborn illusion, that of believing the upstairs is fragranced because the scent was noticeable downstairs just before going up.
Which surface to count in a house on two floors
Count the surface of the level you want to fragrance, not that of the whole house. A living room opening onto a kitchen and a hallway usually stays under 100 m², which is the stated coverage of a living-room device. A bedroom or a shower room upstairs rarely exceeds 10 to 15 m², the coverage of a portable model.
Three markers are enough to do the maths before buying:
- The living level. Living room, open kitchen and hallway form a single volume as soon as the doors stay open: add them up and compare with 100 m².
- The upstairs rooms. Bedrooms and bathroom are volumes separated by doors that are usually closed: each is treated on its own, around 10 m².
- The landing and the stairwell. They connect the two levels without fragrancing them: a device placed there serves both badly instead of serving one well.
Placement counts as much as surface: a flat, stable surface, clear above since the mist leaves from the top, away from the wall and from any ventilation outlet, otherwise the diffusion goes straight into the extraction. The room-by-room detail is in our article on where to place a home fragrance diffuser.
Which diffuser downstairs, which one upstairs?
Downstairs, take the device sized for the living volume: the PURRA X300S covers 100 m², carries a 10,000 mAh battery and is set from a touch interface. Upstairs, a PURRA C30 rated for 10 m² is enough for a bedroom, sits on a bedside table and moves from room to room without a socket.
PURRA, a French brand of home fragrance diffusers using cold nebulisation, builds its range around four devices and six scent refills. The two refill formats are not interchangeable, and that is the point to settle before ordering.
| Model | Coverage | Price on the day of publication |
|---|---|---|
| PURRA X300S, for the living level | 100 m², a living room open onto the kitchen | 199,90 € |
| PURRA C30, portable, for upstairs | 10 m², a bedroom or a shower room | 89,90 € |
The PURRA X300S takes the 100 ml Signature Refill: 625 operating hours on setting I, 400 hours on setting II and 200 hours on setting III, around 78, 50 and 25 days at 8 hours of diffusion per day. The PURRA C30 takes the 10 ml bottle and nothing else, which lasts 333 hours on the gentlest setting, around six weeks on that same basis. For upstairs, the Signature Set and its six 10 ml bottles makes it possible to choose a different scent from the one downstairs.
Setting both devices, in three steps
Set the downstairs device to the middle intensity and the upstairs one to the gentlest: the manuals advise starting on setting II from 100 m² and staying on setting I below 10 m². Staggering the timers then keeps the two scents from meeting on the stairs.
- Size each device on its room, never on the house. Downstairs, a 100 m² model on setting II, that is 15 seconds of mist for 100 seconds of pause. Upstairs, a 10 m² model on setting I, that is 15 seconds for around three minutes of pause.
- Place each device away from the stairwell. A flat, stable surface, clear above, away from the wall and from any ventilation outlet, out of the direct draught of the front door.
- Stagger the timers. The living-room model offers 1 h, 2 h, 4 h and 8 h; the portable model 1 h, 8 h and 24 h. Downstairs the 8 h setting covers the day, upstairs the 1 h setting is enough to prepare a bedroom before turning in.
On scent, two schools are equally valid. Keeping the same one throughout gives the home a single signature. Taking two, a fresh note downstairs and a warmer one upstairs, marks the passage from one level to the other, provided the scent families do not contradict each other. A cleaning cycle of the circuit is due at every change of scent.
Can you stick to a single device?
Yes, provided you accept that only the equipped level will be fragranced. Equip the one where you spend your days and receive guests, usually the ground floor. Moving up the range does not settle the question: a column designed for 180 m² covers one large open volume, not two volumes separated by a floor.
This case has its logic. A house whose upper floor holds only bedrooms needs no fixed device upstairs: a portable device carried up in the evening, set on the 1 h timer, does the same job. At full charge a battery model diffuses around 140 hours on the gentlest setting, around 17 days at 8 hours of diffusion per day, and recharges in around 5 hours, a figure stated by the manufacturer.
The reasoning changes as soon as the upper floor receives visitors: a study a client is taken up to, a guest room, a second sitting room. The second device is then no longer a comfort. The case of the study at home is covered in our article on the gift for a man working from home, and the case of very large open volumes in our review of the column designed for 180 m².
Frequently asked questions
Why does it always smell bad in the same spot in the house?
Because the source is local rather than airborne: a dried-out trap, a damp textile, a cupboard left shut. A diffuser does not treat it. It covers 10, 100 or 180 m² depending on the model, and sits on a flat surface, clear above.
Look for the exact spot first: move along wall by wall, open the cupboards, check the drains you rarely use. In a house on two levels that spot is often downstairs, under the stairs or near the utility room, where the air circulates least. Once the cause is dealt with and the room aired, diffusion takes over and holds the atmosphere, without ever replacing the cleaning itself.
How do you get rid of the smell of shoes in the hallway?
Treat the source before fragrancing: shoes taken out of the closed cupboard, soles dried, the unit opened regularly. A hallway rarely exceeds 10 m², the coverage of a portable diffuser set to the gentlest intensity, that is 15 seconds of mist then around three minutes of pause.
A diffuser covers a smell, it does not remove it, and that distinction matters all the more in a house with an upper floor, whose hallway also receives the air from above when the stairwell stays open. Place the device on a flat console, clear above, away from any ventilation outlet. A 10 ml bottle lasts 333 operating hours on the gentlest setting, around six weeks at 8 hours of diffusion per day.
Can you leave a fragrance diffuser running when there are children at home?
The printed instructions ask you to keep the device and its refills out of reach of children, not to swallow them and to avoid contact with the eyes. Use is possible from the age of 8 under supervision, and the official instruction is to start on the lowest intensity, in a ventilated room.
In a house with an upper floor this guides placement more than settings. A living-room device sits high up, on a flat and stable surface, never on the floor of a corridor people walk through; a 101 cm column is kept away from swing doors to rule out any risk of tipping. On the lowest intensity, diffusion happens in bursts of 15 seconds followed by a pause, never continuously. In case of doubt, the published instruction refers you to a healthcare professional.
How long does it take to fully charge the battery of a cordless diffuser?
Allow around 5 hours for a 2,000 mAh battery and around 6 hours for a 10,000 mAh battery, figures stated by the manufacturer. Charging is over USB-C, and the device keeps diffusing while it is plugged in: nothing obliges you to switch it off.
Running time, on the other hand, depends on the setting. At full charge and unplugged, a 10,000 mAh model diffuses around 293 hours on the gentlest setting, 146 hours on the middle setting and 88 hours on the strongest, around 36 days on the gentlest at 8 hours of diffusion per day. A portable 2,000 mAh model lasts around 140 hours on the gentlest setting, around 17 days on that same basis.
Should you equip both levels straight away or can you start with a single device?
Start with the level where you live, usually the ground floor and its 100 m² of living area, then add a second device for upstairs when the need is confirmed. Nothing obliges you to buy both together: delivery is free from 49 € to France, Switzerland and Monaco.
The only point to settle before buying is the refill format: the PURRA X300S takes the 100 ml refill, the PURRA C30 the 10 ml bottle, and the two formats are not interchangeable. Deciding the level first avoids buying two devices one of which stays switched off. The order leaves within 24 to 48 hours, and a return is accepted within 14 days provided the device has not been used and is in its original packaging.
Do two diffusers in the same home double the cost of refills?
The cost follows the number of diffusion hours, not the number of devices. A 100 ml scent refill lasts 625 operating hours on the gentle setting, around 78 days at 8 hours of diffusion per day, which comes to about 10 € per month and per device.
Two devices each running 8 hours a day do use two refills, but that is rarely what happens in a house with an upper floor: the downstairs one serves during the day, the upstairs one in the evening only. On the middle setting, the same 100 ml scent refill lasts 400 operating hours, around 50 days on that same basis, and 200 hours on the strongest setting, around 25 days.
What happens if one of the two devices breaks down?
Each device is independent: the other keeps diffusing while the case is handled. The legal guarantee of conformity covers a defect that appears within two years of delivery of the goods, and registering the product remains optional, since it conditions no guarantee.
Three situations are not defects of conformity: a fall, immersion and opening the device. Before concluding it has broken down, go back over the mechanical points in order: bottle screwed down to the stop, white transport part removed, collar screwed back on. A clogged circuit is treated with a cleaning cycle, 2 to 3 ml of 70 % isopropyl alcohol in the empty bottle supplied. The two-year period is detailed on the Service-Public.fr page on the legal guarantee of conformity.
For the level where you live and receive guests, the PURRA X300S and its 100 m² of coverage remains the device to install first, before equipping upstairs.
Article published on 14 September 2026 by PURRA.