Is there any heat or burning? No. It is cool mist - the water is broken up by vibration, not boiled. There is no heating element, so no burning oil, no hot steam and no burn risk.
What do I add for aromatherapy scent? A few drops of SOSA's water-based Hotel Collection fragrance in the tank. Never raw essential oils - they are too thick, sit on the plate and clog it.
The plate, the water, the mist
Strip away the marketing and an ultrasonic diffuser is beautifully simple. Three things: a tank of water, a vibrating disc under it, and a little airflow to carry the mist out.
'Ultrasonic' just means vibration faster than human hearing. The disc in the tank oscillates at around 2.4MHz - about 2.4 million cycles a second. At that speed it flings the topmost layer of water off as a cloud of droplets so fine they float. That cloud is the mist.
Because the energy is mechanical - vibration - and not thermal, the water never heats up. Compare that with a warm-mist unit or an oil-burner, which use heat to release scent. The ultrasonic route keeps everything at room temperature, which is why the mist is cool, why there is no burn risk, and why these units are safe to leave running near people.
This is also why an ultrasonic diffuser humidifies: the mist is water. Add scent and it carries scent; add nothing and it simply moistens the air. The same physics does both jobs, which is why every SOSA diffuser is a humidifier and an aroma diffuser at once.
Where the fragrance comes in
The machine makes mist from water. For aromatherapy you need scent in that water - and here is the catch that trips people up. The fragrance has to be water-based, so it dissolves and mists out evenly. That is the whole design brief behind SOSA's Hotel Collection.
The Hotel Collection is a water-based diffuser fragrance in seven hotel-inspired scents. You add a few drops to the tank, top up with clean water, and the ultrasonic plate lifts the scent into the room on the mist. It is composed in India by our own perfumer to fragrance-industry standards and is phthalate-free.
Myth: any essential oil works in an ultrasonic diffuser. Reality: it does not. Raw essential oils and carrier oils are thick and oily; they do not dissolve in water, so they float on the surface, coat the vibrating plate and clog it. A clogged plate mists weakly, then fails. Use only a water-based diffuser fragrance - our Hotel Collection - which is built to ride the mist cleanly.
One honest boundary while we are on the science: an ultrasonic diffuser disperses scent and moisture. It is not an air purifier - it has no filter and does not remove dust, smoke or allergens. Aromatherapy here means a pleasant, evenly scented, comfortably humid room, not clean or medicated air. Run it with clean room-temperature water (filtered or RO in hard-water areas to avoid white mineral dust) and the SOSA water-based fragrance, and the physics will do the rest.
The SOSA range
SOSA makes three cool-mist ultrasonic diffusers for different rooms, each arriving with three of our water-based Hotel Collection fragrances so you can scent from day one. Prices and headline specs below are live from the SOSA store. Whichever you choose, use only the SOSA water-based fragrance - raw essential or carrier oils can clog the misting plate.
| Diffuser / refill | Character | Best for | From |
|---|---|---|---|
| Boond (300ml mini) | USB · up to 6 hrs · colour night light · ~150 sq ft | Desk, bedside, hostel | ₹799 |
| Sukoon (500ml) | 16-18 hrs · 7-colour LED · remote + 2H/4H timers · 270-320 sq ft | Bedroom, study, nursery | ₹1799 |
| Megh (6L) | Up to 100 hrs · adjustable mist dial · ~35 dB · large-room humidifier | Living room, dry AC, winter | ₹3499 |
| Hotel Collection fragrance | Water-based refill · 7 hotel-inspired scents · 15/100/300ml | Refill for any SOSA diffuser | ₹299 |
Versailles
I trained as a perfumer at ISIPCA in Versailles, but half the questions we get are not about scent at all - they are about the machine. Indian rooms are bone-dry from AC and winter, and most gadget diffusers are too small, too loud, or quit by midnight. So we made three: Boond (300ml, desk), Sukoon (500ml, bedroom, with a remote and mood light) and Megh (6L, whole-room), each shipping with three of our fragrances.
They are cool-mist ultrasonic diffusers - an ultrasonic plate turns water into a fine, cool mist with no heating element, so there is no boiling water or burn risk, and each has an auto shut-off when the tank runs dry.
One thing I say on every listing and will say here: use only SOSA's water-based Hotel Collection fragrance. Raw essential oils, perfumes and carrier oils are thick or solvent-heavy and can clog the misting plate and damage the unit. A few drops of our water-based fragrance in the tank mists cleanly and scents the whole room.
Frequently asked questions
Facts verified June 2026: SOSA makes three cool-mist ultrasonic diffusers: Boond (300ml, USB, colour night light, up to 6 hrs, ~150 sq ft, ₹799), Sukoon (500ml, 7-colour LED, remote + 2H/4H timers, up to 16-18 hrs, 270-320 sq ft, BPA-free, ₹1799) and Megh (6L, adjustable mist dial, ~35 dB, up to 100 hrs, ₹3499). Each is cool mist (no heating element) with auto shut-off, ships with 3 water-based Hotel Collection fragrances (15ml ₹299 / 100ml ₹999 / 300ml ₹1799), and is made for Indian AC-dry and winter air. Use SOSA water-based fragrance only; raw essential or carrier oils can clog the ultrasonic misting plate. Composed in India; a portion of every order supports Nanhi Kali girl-child education. These are independent, hotel-inspired fragrance interpretations created by SOSA. SOSA is not affiliated with, endorsed by or associated with the hotels named; all hotel names are trademarks of their respective owners and are used only to describe the scent style.