Recirculating or ductless: passes air through a grease filter and a charcoal filter and returns it to the room. Removes grease and adsorbs some odour; removes no air, no heat and no moisture. Much weaker, and common in Indian flats where no external wall opening was ever cut.
What then decides whether a ducted one works: suction rating in m³/h against kitchen volume, duct length and the number of bends, hood size and height over the hob, filter condition, and whether the flat has any make-up air path at all. Mesh filters degreased monthly; charcoal filters replaced every six to twelve months, because they cannot be washed.
2. A recirculating chimney is a filter, not an extractor. Air passes through a mesh or baffle filter for grease, then through an activated charcoal cartridge which adsorbs a portion of the odour molecules, and then back into your kitchen. No air leaves. No heat leaves. No moisture leaves. It is meaningfully weaker, and it is very common.
3. Find out which one you have before doing anything else. Look for a pipe that actually goes outside, feel for air blowing back out of the top of the canopy, and check whether there is a carbon cartridge behind the grease filter. Five minutes, and it changes every decision after it.
4. For a ducted one, four things decide the result: suction in m³/h against your kitchen's volume, the length of the duct and how many bends are in it, how well the hood covers the hob and how high it sits, and whether the flat gives the fan any replacement air at all.
5. Then the maintenance nobody does. Mesh and baffle filters degreased monthly in hot water with washing soda. Charcoal filters replaced every six to twelve months, because they cannot be washed and a saturated one is doing nothing.
6. Fragrance is for afterwards, not instead. A good ducted chimney, run correctly, does most of the work. Then a Sukoon at ₹1,899 with four drops of a Hotel Collection scent at ₹299 gives the room a level of its own.
A portion of every order supports girl-child education through Nanhi Kali.
Which of the two you actually own
Before any specification is worth reading, settle this, because the two machines are sold side by side and look almost the same. A ducted chimney is connected to a pipe that terminates outside the building. A recirculating chimney is not connected to anything: it draws air in, pushes it through filters and blows it back into the kitchen through vents in the top of the canopy. A great many flats in this country have the second, sometimes because the building never permitted an external opening, sometimes because the installer avoided cutting one, and occasionally because a ducted unit was fitted with a duct that stops inside a false ceiling and vents into the space above your kitchen — which is the worst of all arrangements and more common than anybody admits.
What decides whether a ducted one works
The two types side by side, then the four variables that separate a chimney doing its job from one making a noise. The last column is what to actually do about each, and most of it costs nothing beyond an afternoon and a replacement cartridge.
| Type or factor | What it does with the air | What it removes | What it does not | What to do |
|---|---|---|---|---|
| Ducted chimney ★ | Carries it through a duct to outside the building | Air, heat, moisture, grease aerosol and odour — because the air itself leaves | Anything released outside the hood's capture zone, which is a separate problem | Keep the duct short, wide, rigid and straight; degrease the filters monthly |
| Recirculating / ductless | Filters it and blows it back into the kitchen | Grease at the mesh, and a share of odour molecules adsorbed onto activated carbon | Air, heat or moisture — none of it leaves the room. Much weaker, and very common | Replace the charcoal cartridge every 6–12 months; ventilate properly alongside it |
| Suction rating vs volume | Decides how many times an hour the kitchen's air can pass the hood | Nothing on its own — it is a ceiling on performance rather than a guarantee | It does not survive the duct. Ratings are measured with no duct fitted | Kitchen volume × 10–15 as a floor. Around 1,000–1,200 m³/h for Indian frying |
| Duct length and bends | Every metre and every 90° bend costs static pressure and real volume | — | A six-metre run with three bends delivers a fraction of the rated figure | Short, straight, wide, rigid. Avoid flexible corrugated pipe and any reduction in diameter |
| Hood size and height | Sets the capture zone the plume has to rise into | Only what is actually underneath it | Front burners on a hood no wider than the hob; a plume that has spread before it arrives | Hood at least as wide as the hob, 65–75 cm above it. Cook on the back burner |
| Filter condition | A clogged filter is resistance, and resistance is lost airflow | Less every month, without any fault developing | Nothing you would notice as a failure — it simply weakens | Mesh and baffle soaked monthly in hot water with washing soda. Charcoal replaced, never washed |
| Make-up air | Decides whether the fan can move its rated volume at all | — | A sealed flat throttles its own extraction quietly | One window open on the far side while the chimney runs. Free, and it works immediately |
The maintenance nobody does, and where fragrance sits
Put the maintenance on a calendar, because this is a machine whose decline is invisible. Mesh, cassette or baffle filters out and soaking monthly: near-boiling water, three or four spoons of washing soda, twenty to thirty minutes, a stiff brush, a hot rinse and a full dry before refitting. Nothing about a clogged filter announces itself — there is no noise, no error and no visible fault, only a machine that moves less air each month than it did the month before, until one evening you conclude that chimneys do not work. Charcoal is the one people genuinely do not know about. An activated carbon filter has an enormous internal surface area and works by holding odour molecules on it; when that surface is occupied it is finished, and it cannot be washed, rinsed, sun-dried or baked back into service. Six to twelve months, depending on how much frying happens, and the replacement is a specific part number for your model rather than a generic pad. If you own a ductless chimney and have never replaced the cartridge, the honest conclusion is that the odour half of your machine has not functioned for years. Beyond the filters: wipe the underside and the inside of the canopy while it is still warm from cooking, which takes seconds and prevents the afternoon described in the oil-film page in this group; check the duct cowl outside for a bird nest or a jammed backdraught flap, which is a real and frequently missed fault; and if the duct runs through a false ceiling, satisfy yourself that it terminates outside the building rather than in the void.
Then the operating habits, which cost nothing and change the result more than most upgrades would. Run it before the pan is hot and for ten minutes after the hob goes off, and use the high setting for tempering and frying rather than treating high as an emergency measure. Open a window on the far side of the flat while it runs, because a fan that cannot get replacement air into the building cannot get air out of it, and the machine will otherwise spin at its rated speed while moving a fraction of its rated volume. Cook on the back burner where the hood covers you. And be realistic about what even a good installation can do: a chimney captures the plume rising into its capture zone, so a wide pan throwing aerosol sideways, an open pot at a simmer and the burst of a tadka are all partly outside its reach — which is the subject of the opening page in this group and is not a fault in your machine. If, having checked all of this, you conclude you have a recirculating unit and cannot duct it because the building will not allow an external opening, the answer is not despair and it is certainly not fragrance. It is to keep the carbon fresh, run the unit properly, and treat cross-ventilation as the main event rather than the afterthought: two openings on opposite or adjacent walls for twenty minutes after cooking will out-perform any ductless chimney ever made, and it is free.
Then fragrance, and I want the framing to be exact. A chimney and a diffuser are not competing purchases and they are not the same order of magnitude. Extraction moves hundreds of cubic metres of air an hour out of a building. A cool-mist ultrasonic puts thirty to fifty millilitres of water an hour into a room. One removes; the other adds. Nothing I sell substitutes for the machine over your hob, and running a scent while the kitchen is working gives you two smells that meet in the doorway. What fragrance is for is the two hours afterwards, on air the extraction has already cleaned: four drops per tank in a kitchen or a kitchen-adjacent living room, three in a small flat, the dose being per tank rather than per litre since you are scenting the mist and not the water — so a 300ml Boond at ₹899 takes the same four drops as a 500ml Sukoon at ₹1,899, and the larger machine buys hours and coverage rather than intensity. The Sukoon covers 270–320 sq ft, runs 16–18 hours per fill on low at 30–50 ml/h against 9–12 on high, has a 2.4MHz plate, a remote, auto shut-off and steady, 2H and 4H timers, and includes three 15ml Hotel Collection scents of your choice. Start it on the 2H timer when the chimney goes off, not before. On format: a candle such as Bookshop candle at ₹379 gives scent in fifteen to twenty minutes and must be attended and put out; a reed diffuser from ₹749 needs twenty-four to seventy-two hours and then holds one level for months, making it right for a habit and wrong for tonight; and SOSA makes no room or linen spray for the home, since the sprays in the range are car perfumes. Keep any of it out of the direct plume and away from the hob, and remember that a cool mist adds water, which in a monsoon month in a kitchen that already runs humid is a reason to choose the candle or the reed instead.
The SOSA edit
In the order that answers the question in the title. The first four rows have no price on them at all, and the fifth is a part you buy from whoever made your chimney rather than from me. Only the last two are things SOSA sells, and both belong to the hour after the extraction has finished.
| Do | What it is | Why it is in this position | Cost |
|---|---|---|---|
| 1. Find out which type you own ★ | Follow the pipe, hold a tissue at the top vents, look behind the grease filter for a carbon cartridge | Ducted removes air; ductless filters and returns it. Every decision after this depends on the answer | ₹0 |
| 2. Give it make-up air | One window open on the far side of the flat for as long as the chimney runs | A fan that cannot get air in cannot get air out. This changes performance more than an upgrade would | ₹0 |
| 3. Run it early, late and high | On before the pan is hot, high for tempering and frying, off ten minutes after the hob | The most loaded air of the session is in the room at the moment you finish cooking | ₹0 |
| 4. Degrease the filters monthly | Mesh or baffle in near-boiling water with washing soda, 20–30 minutes, brushed, rinsed and dried | A clogged filter is resistance, and resistance is lost airflow. The decline is completely silent | ₹0 |
| 5. Replace the charcoal filter | Every six to twelve months. Activated carbon cannot be washed, dried or revived | A saturated cartridge does nothing at all for odour, and most ductless owners have never changed one | Your chimney brand |
| 6. Sukoon or Boond | 500ml with steady/2H/4H timers and three 15ml scents included, or 300ml for a smaller space | Afterwards, on the 2H timer, four drops per tank. Never while the kitchen is still working | ₹1,899 / ₹899 |
| 7. Reed diffusers or a candle | Alcohol-free reeds holding one level for months, or an 80g candle at roughly 15–18 hours | The reed for a habit, allowing 24 to 72 hours; the candle for tonight, attended and put out | from ₹749 / ₹379 |
Versailles
I get asked this by people who are about to buy a diffuser because their chimney has disappointed them, and the answer nearly always turns out to be that the chimney is ductless and nobody told them. A recirculating unit filters air and gives it back to you. It is a genuinely useful thing — it takes grease out of the air, which protects your kitchen — but on odour it is doing a fraction of what its owner believes, and once the carbon cartridge is saturated it is doing nothing at all. Five minutes with a torch behind the grease filter has saved more of my customers more money than anything I have written.
And where a ducted one is fitted, the failures are almost always installation rather than the machine: a long flexible duct with three bends, a hood no wider than the hob, or a flat so well sealed that the fan cannot draw replacement air. None of that is fixed by fragrance, and I would think less of myself for suggesting it was. A good ducted chimney, correctly sized and short-ducted and actually maintained, does most of the work in a kitchen — more than any product in my range does, by a wide margin. What I sell begins two hours later, on air that has already been changed, when the room is clean and you would like it to smell of cedar and vetiver rather than of nothing. That is a real thing to want, and it is a small thing next to the extraction. I would rather be honest about the proportions.
Everything is made and supported from Pune, and a part of every order funds girl-child education through Nanhi Kali. You get a home that smells like somewhere you chose; a girl gets a classroom. That equation has always felt right to me.
Frequently asked questions
- Why a 1BHK smells of food despite a chimney — what a hood physically captures, and the three routes it misses.
- Why the kitchen smells of oil after cleaning — the filters you have just taken out, and the film on everything above eye level.
- Will a diffuser cover a cooking smell, honestly? and why an open kitchen makes the whole flat smell of dinner — the two questions this one leads to.
- The complete order in which to fix a home that smells of cooking — the pillar guide for this group.
- Brand: the SOSA founder story.
Facts verified August 2026: Diagnostic facts used in this guide: a closed room accumulates what it cannot exchange, so cross-ventilation needs two openings rather than one; a drain's U-bend water seal evaporates in roughly two to four weeks of disuse and then admits sewer gas, which is corrected by pouring water down the drain; microbial growth in fabric and on surfaces accelerates above about 60% relative humidity, and Indian monsoon indoor humidity commonly runs 80–95%, which is the one situation where ventilating on a wet day can import moisture rather than remove it; an air-conditioner's cold, wet evaporator coil and filter grow biofilm that is blown into the room on start-up; textiles adsorb cooking aerosol and body oils and re-release them for weeks; and olfactory adaptation makes a constant household smell undetectable to its residents within about a fortnight while visitors still perceive it. Timings: a scented candle scents a normal room in roughly 15–20 minutes, a Sukoon ultrasonic diffuser reaches a steady level in about 20 minutes from cold, and a reed diffuser needs roughly 24–72 hours. SOSA products and prices: Sukoon 500ml ₹1,899 (270–320 sq ft, 16–18h on low, 9–12h high, 30–50 ml/h, 2.4MHz cool mist, remote, steady/2H/4H timers, BPA-free, auto shut-off, includes three 15ml Hotel Collection scents of your choice); Boond 300ml ₹899; Megh 6-litre ₹3,499; waterless Vaayu ₹11,999 (up to 1000m³); Aangan ₹25,999. Hotel Collection water-based fragrance 15ml ₹299, 100ml ₹999, 300ml ₹1,799, Pack of 7 at 15ml ₹1,799; dose 3–6 drops per tank. Reed diffusers (separate alcohol-free line): Morning Freshness from ₹749, Garden Bloom and Evening Calm from ₹799, Fresh Brew and Mountain Breeze from ₹849; 130ml from ₹1,249; duos from ₹1,498; 300ml refills ₹2,399. Scented candles: Bookshop 80g ₹379, Amber Rose 130g ₹599 and 220g ₹799, Smoked Oudh 130g ₹449, ceramic jar candles ₹949, Pure Calm wax melt set ₹854. Free shipping above ₹499. SOSA does not make a room or linen spray for the home. The Hotel Collection scents are SOSA's own interpretations; SOSA is not affiliated with or endorsed by any hotel brand. Prices subject to change — see the live product pages.