Best Dehumidifier for Nursery: 8 Quiet Picks and a Placement Checklist

It is 2 a.m., the baby is finally down, and the room feels muggy and smells a little like wet laundry. That is when most parents start searching for the best dehumidifier for a nursery. The short answer: pick a small, quiet tank model with auto shutoff and a way to turn off its lights, and place it where the cord and the tank are nowhere near the crib. The TABYIK 35 oz is our top pick because its title is the only one in this group to give a sound figure, 28 dB. If you would rather empty a tank less often, three 95 oz units with sleep mode are the next step up.

This guide makes no medical claims. We do not say a dehumidifier prevents any illness, and we do not tell you what humidity your baby needs. We compare hardware on the things a parent can check: noise claims, tank size, shutoff, cords, lights and room-size ratings. The Editorial team worked from listings, manufacturer documentation and buyer reviews, and nobody on the team used or measured these units.

What a nursery asks of a dehumidifier

TABYIK 35 OZ Dehumidifier for Bedroom RV, Quiet with Auto Shut Off, White | 280 Sq.Ft Small Dehumidifiers for Home Bathroom Closet, 7 Color Light, 28dB Ultra Quiet, 35OZ Water Tank

One of the moisture-control product options compared in this guide.

View on Amazon →

Small Dehumidifier for Home 44OZ Quiet with Auto Off & Defrost 5 Timers 3 modes 10 Color Lights 3 Brightness 260 Sq.ft Portable Dehumidifiers for Basement Bedroom Bathroom RV Closet

One of the moisture-control product options compared in this guide.

View on Amazon →

Windangel 44oz(1.3L) Small Dehumidifier for Home Auto-Off Quiet Portable Dehumidifier with 3 Modes 10 Color Lights 4 Timer Settings for Bedroom Bathroom Closet (215 sq.ft)

One of the moisture-control product options compared in this guide.

View on Amazon →

ToLife Dehumidifier, 1000 Sq Ft 95 oz Tank with Sleep Mode, Auto Shutoff | Portable for Home, Bedroom, Bathroom and Basement with 7-Color LED Light, White

One of the moisture-control product options compared in this guide.

View on Amazon →

BEDRED Dehumidifier, 95Oz Dehumidifier for Home 1000 Sq.Ft | Quiet, Auto Shutoff, Sleep Mode, 7 Color Ambient Light for Bedroom, Bathroom, Basement (Black)

One of the moisture-control product options compared in this guide.

View on Amazon →

Dehumidifier 1657ML 58OZ Small Dehumidifier for Home 230 Ft² Safety Dehumidifiers Adjustable 10 Color Lights 5 Timers 3 Setting Modes Auto Shut Off Protection Low Noise For Bedroom Bathroom

One of the moisture-control product options compared in this guide.

View on Amazon →

Dehumidifiers for Home, 1000 Sq Ft Dehumidifier with 95oz Tank Auto Shutoff | Quiet for Bedroom, Bathroom and Basement with Sleep Mode 7-Color LED Light, Grey

One of the moisture-control product options compared in this guide.

View on Amazon →

NeedDuck Dehumidifier for Home Small Quiet Dehumidifiers for 44OZ Water Tank Auto Defrost and Shutoff 10 Colors Light 4 Timer Options 3 Modes Portable Dehumidifiers for Bedroom Bathroom Closet RV

One of the moisture-control product options compared in this guide.

View on Amazon →

A nursery is a small room with unusual rules. It is a room where you want quiet for long stretches, a dark space at night, safe cords, and the freedom to ignore the machine for a few days. Those priorities differ from a basement unit that runs hard in a big space.

Start with the humidity target. Commonly cited indoor comfort guidance puts relative humidity at roughly 30 to 50 percent, and that is a household guideline rather than health advice for infants. Your pediatrician is the right person to ask what they want for your baby and your climate. Whatever the number, you need your own digital hygrometer in the room, placed near the crib at mattress height but out of reach, because the display on a small dehumidifier is a convenience reading.

Then ask what the unit does when it is full or when something goes wrong. Auto shutoff when the tank fills is in the title of most of the units here. That matters at 3 a.m., when nobody wants to find a tank overflowing. Treat it as a minimum requirement.

Last, remember what a dehumidifier cannot do. It does not clean the air of dust or pollen, and it does not replace fixing a leak, a damp wall or a closed-off room with no airflow. If you see mold on a wall, the fix is the source of the moisture, and a machine alone will not solve it.

A nursery placement checklist

Use this list before you plug anything in. It is the part of the guide you can print.

1. Read the manual first. The manufacturer’s instructions override anything written here.
2. Pick a hard, level, stable surface. A floor corner away from the crib is typical. Never place it on a soft rug, a changing table or a shelf the baby could ever reach.
3. Measure the cord distance. Stretch your arm across the crib rail, then double that reach. The unit and its cord should sit beyond it.
4. Route the cord along the wall. Tuck it behind a dresser or secure it with cord covers. Avoid any loop at toddler height. A direct wall outlet is better than a power strip or an extension cord, if the manual allows.
5. Leave clearance. Keep several inches of open space around the air intake and outlet. Blocking them hurts performance and can cause overheating.
6. Turn off the lights. Many of these units have 7-color or 10-color lights. A dark nursery stays dark, so check that the light can be switched off or at least dimmed to the lowest setting.
7. Plan the tank routine. Pick a time of day to empty it, and carry the tank carefully to a bathroom rather than the nursery sink.
8. Add a hygrometer. Put it near the crib, out of reach, and look at it for a week before changing settings.
9. Do a daytime trial. Run the unit with the baby elsewhere and note every noise, light and click.
10. Re-check monthly. Cords loosen, filters collect dust, and tanks develop film.

Reading noise claims without a decibel meter

Noise is the whole reason people shop for a quiet nursery model, and it is the hardest thing to judge from a listing. Of the eight titles, only the TABYIK states a number: 28 dB. For a rough reference, many guides put a quiet library near 30 dB and normal conversation near 60 dB, so 28 dB would be very quiet if it holds. This is an estimate based on a title claim, not our measurement.

Other titles use words such as quiet, low noise, ultra-quiet or sleep mode. Those are marketing terms. Sleep mode normally means lower fan speed or dimmed lights, and the three 95 oz models list it. Whether it also silences clicks or the sound of water in the tank is a question for the listing and buyer reviews.

Noise has three flavors. Fan hum is steady and often masked by a white noise machine. Compressor-style cycling is a periodic thump. Water noise is a gurgle or drip. In this price class, many small tank units are thermoelectric rather than compressor models, which generally means no compressor thump but lower water removal. That is general knowledge, not a claim about any one listing, so check the listing for the type.

A practical test is the room trial. Run the unit in the nursery for an evening while you are in the room and stay quiet. If you notice it, a sleeping baby’s parent probably will too.

Sizing for a small room: a worked example

A typical nursery measures about 11 by 12 feet, which is 132 square feet. With 8-foot ceilings that is 1,056 cubic feet of air. The smaller units on this list state 215 to 280 square feet of coverage, and the three big-tank units state 1,000 square feet. On paper everything covers the room.

In practice, a stated area is a maximum under manufacturer-chosen conditions, so look for headroom of at least 1.5 to 2 times your room. A 132 sq ft room points to 215 sq ft or more, which includes everything here. The next question is how often you will refill the tank, and that depends on how wet the room is.

How long a tank lasts: an estimate with stated assumptions

Assume, for illustration only, that a unit pulls 16 oz of water during an 8-hour night. Your number could be much higher in a damp basement room or near zero in a dry one. Under that assumption:

If your nursery is damp enough that a unit fills a tank each night, the 95 oz models are easier. If you only need to shave a few points off the hygrometer reading, the 35 oz tank may rarely fill.

What it might cost to run

The titles give no wattage, so check the listing. As an illustration, a 30-watt unit running 10 hours a day for 30 days uses 9 kWh. At an assumed 16 cents per kWh, that is about $1.44 a month. A 200-watt unit on the same schedule uses 60 kWh, or about $9.60 a month. Replace the wattage with the figure on your listing to get your own estimate.

Top picks at a glance

Price tier is relative to this list. Key specs come from the titles; anything not in a title, check the listing.

Small-tank models for small rooms

TABYIK 35 oz Dehumidifier: the quiet claim leader

The TABYIK is our top pick, with a caveat: the main reason is that its title is the only one that states a decibel figure. The listing says 28 dB ultra quiet, a 35 oz water tank, auto shut off and 280 square feet of coverage, with a 7-color light and a white finish. It is the lowest-priced unit in the group.

That 28 dB number is a claim in a title, and the Editorial team cannot confirm it. Still, a stated figure gives you something to hold the seller to, and it gives you a number to compare against anything you can measure with a phone app in your own room.

The small 35 oz tank is both the selling point and the drawback. By the estimate above it fills in about two nights if it pulls 16 oz per night, so it fits best in a nursery that is only mildly damp. In a damp room you will be emptying it daily. The auto shut off is what you want to see when that happens.

The 7-color light needs attention. Look for an off option in the listing or manual. If it cannot be turned off, plan on facing it away from the crib or covering it with something the manual allows.

A fair question is whether a bedroom-and-RV style unit belongs in a nursery at all. The title lists bedroom, RV, bathroom and closet uses, so it is a general small-space product, and the nursery fit comes from its size and noise claim. Compare it with a baby monitor in the same room: if the monitor’s audio picks up a hum you did not notice, move the unit farther away.

Pros

• Only title with a stated sound level, 28 dB
• Auto shut off when the tank is full
• Lowest price tier in the group

Cons

• 35 oz tank fills quickly in a damp room
• Light behavior is unclear from the title
• The 28 dB claim is unverified by us

Who it’s for: parents of a mildly damp nursery who put noise first and do not mind a daily tank routine.

BeOkay 58 oz Dehumidifier: the middle tank

BeOkay’s title reads “1657ML 58OZ” with 230 square feet of coverage, “safety” in the name, adjustable 10 color lights, five timers, three setting modes, auto shut off protection and low noise. The tank is the mid-size option here, larger than the 35 and 44 oz units and smaller than the three 95 oz models.

For a nursery, the useful pairing is the five timers and the auto shut off. A timer can stop the unit before an early-morning feed so a hum does not intrude, or run it for a few hours before bedtime and then switch off. The adjustable lights are described as adjustable, which suggests you can turn them down; confirm in the manual that they can be turned off.

The “low noise” wording gives no number. If the TABYIK’s 28 dB is your benchmark, ask the seller or check buyer questions for a figure before choosing this one for noise alone.

At 58 oz, the estimate on the tank-life table is roughly three and a half nights at 16 oz per night. That is a middle path: less routine than the 35 oz tank, and a smaller footprint than the 95 oz units.

Because the listing leans on safety wording, check what that covers in the manual. Typical safeguards on small units include shutting off when the tank is full or when the tank is removed, and some add overheat protection; the title only confirms auto shut off protection. A specific habit helps here: after you empty the tank, seat it firmly and watch for the unit to restart before you leave the room, so you never find out at 3 a.m. that it has been idle for hours.

Pros

• 58 oz tank with five timers
• Auto shut off protection in the title
• Budget price tier

Cons

• No decibel figure
• Coverage rating is modest, 230 sq ft
• Light off option is unconfirmed

Who it’s for: parents who want a timer-controlled schedule and a tank that lasts a few nights.

Newo 44 oz Small Dehumidifier: five timers and three brightness levels

The Newo, listed as “Small Dehumidifier for Home 44OZ,” offers auto off and defrost, five timers, three modes, 10 color lights with three brightness levels, and 260 square feet of coverage. The brand name is not in the title; it comes from the product data.

The three brightness settings are the nursery-relevant detail. Lowest brightness is still a light in a dark room, so look for confirmation that the lowest setting is dim enough, or that off is available. “Auto defrost” is a feature that helps a unit keep working in cooler rooms, and it matters if the nursery is on the north side of the house or in a basement.

Five timers give flexibility, but timers on small units often count hours from the moment you press the button, so check the manual for whether they run from now or at a set clock time. A baby’s schedule moves a lot, and a timer that runs from a fixed button press helps more than one that needs resetting.

The 44 oz tank is a common size for this category. By our illustrative estimate, it fills in roughly two and three-quarters nights at 16 oz per night.

One more practical point is the listing’s description of modes. Three modes usually means something like continuous, auto-humidity and a quieter or sleep setting, but the title does not say, so read the manual. If one mode holds a humidity target, it is the one to leave on overnight, since it cycles off when the room reaches the setting. Combine that with your own hygrometer by the crib to see whether the target holds across a full night.

Pros

• Three brightness levels for the light
• Auto off and defrost
• Five timers

Cons

• Brand name does not appear in the listing title
• No noise number
• Light can’t be confirmed as fully off

Who it’s for: a parent who wants fine control over brightness and schedule in a small room.

Windangel 44 oz (1.3 L) Dehumidifier: the smallest-room pick

Windangel’s title states 44 oz (1.3 L), auto-off, quiet, portable, three modes, 10 color lights, four timer settings and 215 square feet. It has the smallest coverage number in the group, which is not a flaw for a nursery under 150 square feet but is a warning for anything bigger.

Because the stated area is only 215 square feet, the headroom rule from the sizing section matters. A 132 sq ft nursery is within the rating, with a comfortable margin. A 200 sq ft room is close to the limit, and you would be asking the machine to work near its maximum.

The “portable” word suggests a carry handle or lightweight build, but the title does not say. Check the listing for the weight and how the tank is removed. A tank that sloshes on the way to the bathroom is a quiet-hours nuisance.

The four timers are fewer than the Newo and BeOkay, which may be fine. Many parents use one fixed routine anyway: on during the evening, off before morning.

The 1.3 L figure also helps with planning. That is a smaller volume than a gallon jug, so a damp week can fill it quickly. If you notice the unit stopping often, it may be doing its job and shutting off at full, so a quick daily check at the same time each morning becomes part of the routine. Pair it with a towel or tray under the unit in case of drips when you carry the tank.

If you run it at the lowest timer setting, listen once for the click when it switches off, since some small units make a soft pop at shutoff.

Pros

• Clear 1.3 L tank size in the title
• Auto-off included
• Budget price tier

Cons

• Lowest coverage figure, 215 sq ft
• No noise figure
• Fewer timers than some rivals

Who it’s for: a small nursery, 150 square feet or less, where a compact unit is enough.

NeedDuck 44 oz Small Quiet Dehumidifier: the basic tank model

NeedDuck’s listing says small, quiet, 44 oz water tank, auto defrost and shutoff, 10 color lights, four timer options and three modes, for bedroom, bathroom, closet and RV. Unlike the others, it gives no square-foot rating at all. That is a reason to ask questions, because you cannot compare it to a nursery size on paper.

The missing coverage number turns the buying decision into a small bet. For a very small room, say a nursery under 100 square feet, it is probably fine. For a larger room, other units in this list give you a figure to plan around.

On the plus side, it has the features that matter: auto defrost, auto shutoff and timers. It sits in the lower price tier, close to the TABYIK.

Like the others, the lights need a plan. If the listing or manual does not show an off option, assume you will place the unit so the light faces a wall.

Because the coverage is not stated, a cautious buyer can run a simple check. Put a hygrometer in the room, run the unit for a day with the door closed, and see how far the reading drops. If it makes little difference in a day, the room may be too large or too wet for a unit this size, and one of the larger-coverage models in this list would be a better match. Returns are easier before the first week passes.

Its bedroom-bathroom-closet-RV wording tells you the maker thinks of it as a utility product, so do not expect nursery-specific touches; judge it on tank, shutoff and timers alone, and set your own expectations for the lights.

Pros

• Auto defrost and shutoff
• Four timers and three modes
• Low price tier

Cons

• No coverage rating in the title
• No noise figure
• Color lights, off option unconfirmed

Who it’s for: a small, closet-sized nursery where you want basic features at a low price.

Big-tank models for fewer refills

The three 95 oz units are close cousins. Their titles are nearly identical: 1000 square feet, 95 oz tank, auto shutoff, sleep mode and a 7-color light. Differences show up in color and maker. If one of these fits your routine, pick on finish, price on the day and whatever the listing says about noise and drain options.

ToLife 95 oz Dehumidifier, white: the bright finish

ToLife lists 1000 sq ft, a 95 oz tank, sleep mode, auto shutoff and a 7-color LED light, for bedroom, bathroom and basement use. The white finish is a plus in a bright nursery, and a minus if a bright unit glows in the dark.

The 95 oz tank turns the daily chore into a weekly one on our illustrative numbers, about six nights at 16 oz per night. For night-shift parents, not having to carry a tank every morning is worth a lot. The cost is size and weight. A full 95 oz tank holds about three quarts of water, and carrying that carefully matters.

Sleep mode is the other draw. Check what it does: dimmed lights, lower fan speed, or both. Ask whether the sound also changes.

The 1000 sq ft rating is far more than a nursery needs. That headroom means the unit is unlikely to run flat out in a small room, which in theory keeps the fan calmer, though the title does not promise that.

Placement deserves thought with a unit this big. A full tank adds weight, and a tipped tank spills near the floor-level outlet, so choose a spot where the unit stands on a flat surface with space to slide the tank out straight. Keep the carry route in mind, too: from a nursery to a bathroom sink is often a hallway with a closed door and a sleeping baby, so check the tank handle design on the listing.

Buyer questions on the listing are the place to ask about drain-hose support, since a continuous drain would remove the heavy tank carry entirely and the title does not say either way.

Pros

• 95 oz tank, roughly six nights on our estimate
• Sleep mode and auto shutoff
• Large coverage headroom

Cons

• Bigger footprint and heavier full tank
• No noise figure
• Mid-range price tier

Who it’s for: parents who want the fewest tank trips and have floor space to spare.

BEDRED 95 oz Dehumidifier, black: the dark finish

BEDRED’s title covers 95 oz, 1000 sq ft, quiet, auto shutoff, sleep mode and a 7-color ambient light, in black. It shares nearly everything with the ToLife and NineSky, so the decision is partly aesthetic and partly about which listing answers your questions best.

A black unit blends in at night, which helps if you share a nursery with a sleeping baby and want less visual glow. Black can also show dust, so expect to wipe it down.

The title uses the phrase “ambient light.” That suggests a decorative light and not a status indicator, so look for whether a separate small power or tank-full indicator exists, since you will want to see that status at night without a color show.

As with the other two large units, the dimensions and weight are not in the title, and you should compare them with the floor space you have. A narrow spot behind a dresser may not fit a tall unit.

The Editorial team found nothing in the title that separates it on performance from the others in the trio, so we would not pay a premium for it.

A practical suggestion is to decide by which listing gives you the most documentation. A unit with a clear manual download, a stated warranty and an answered buyer-question section beats a nearly identical one with no paper trail, because a nursery is not the place to guess at settings. Check for the support contact in the listing, and save a copy of the manual to your phone before the box is recycled.

Ask also about the tank handle and the shutoff indicator, since a full 95 oz tank is the heaviest thing you will carry in this routine.

Pros

• 95 oz tank with sleep mode
• Black finish blends in at night
• Auto shutoff in the title

Cons

• Light behavior unconfirmed
• Large footprint
• No noise figure

Who it’s for: parents who want the big tank in a darker finish.

NineSky 95 oz Dehumidifier, grey: the neutral finish

NineSky’s listing, titled “Dehumidifiers for Home,” carries the same core features as the others in the trio: 1000 sq ft, 95 oz tank, auto shutoff, quiet, sleep mode and a 7-color LED light, in grey. The brand appears in the data, not in the title.

Grey is the safe choice in many rooms, neither bright white nor stark black. If aesthetics matter and you want the unit to disappear against a wall, this finish is the one.

The question to ask of all three 95 oz units is how their sleep modes differ. Titles repeat the name but not the behavior. Look at buyer questions on each listing for reports about fan speed in sleep mode, whether the display goes dark and whether the light has a true off.

All three share the same tradeoff: more tank and more coverage in exchange for more bulk. For a standard nursery, the bulk is the main thing to weigh.

If you are torn between the three, here is a tiebreaker. Choose the finish that suits the room, then read the most recent buyer questions on each listing. The one whose answers clearly explain sleep mode, light control and tank removal is the one the seller supports. Do not pay extra for a color, and do not skip reading the manual because the titles look identical; hidden differences often live in the drain options and warranty.

Finish aside, the trio’s real difference is likely service: warranty length, replacement parts and reply speed, none of which the titles state.

Whichever of the three you pick, keep the receipt and the box for the first month, so a unit that turns out louder than you hoped can go back.

Pros

• 95 oz tank and sleep mode
• Neutral grey finish
• Auto shutoff

Cons

• Brand not in the title
• Largest footprint in the group
• No noise number

Who it’s for: parents who want the big-tank trio in the most neutral color.

What to skip in a baby’s room

The angle for a nursery is as much about what to leave out as what to include. Three feature types are worth avoiding or at least questioning.

Ozone output. Some appliances in the air-quality aisle generate ozone on purpose. A dehumidifier has no reason to, and none of these titles mention it. If a listing for any unit advertises ozone or ionizing functions, skip it for a baby’s room.

Scented or aromatherapy functions. They add airborne fragrance to a room where a baby sleeps. None of these eight titles mention fragrance, but keep the rule in mind when you browse beyond them. Scented filters or pads fall into the same bucket.

Color light shows. A 7-color or 10-color light is entertainment, not function. In a nursery it is a source of glow at the wrong time. Pick a unit where the light can be turned off, and confirm it before you buy.

If you are also thinking about air quality, our guide to the best air purifier for a nursery covers the other half of the room’s air, which a dehumidifier does not touch.

How we picked these

The Editorial team compared eight listings using published specifications, manufacturer documentation and buyer reviews. Nobody on the team used or measured these units, so there is no claim here that we heard them run or checked their lights at night. What we did was read each title closely, extract the stated tank size, coverage, features and noise claims, and group them by the situation they fit.

We weighed five factors: stated noise claims, tank size and refill burden, auto shutoff and defrost features, light behavior and room-size rating against a typical 100 to 200 square foot nursery. We called out anything missing from a title as “check the listing” rather than guess. Estimates, such as the tank-life table and running cost, are labeled and use assumptions that you can replace with your own.

Buyer reviews helped us build the list of things to ask. Repeated themes in this category include light brightness at night, tank-fill noise, water drips when removing the tank and fans that are louder than expected. We did not count stars or reviews, since both change. For a baby’s room, the manufacturer’s manual and your own daytime trial matter more than any article.

Where this fits with the rest of the nursery

A dehumidifier is one small piece of a nursery setup. If you are still choosing seating for night feeds, our explainer on how to choose nursery gliders covers what actually matters, and the guide to choosing premium nursery furniture sets helps with layout. Leaving space for a floor-level dehumidifier and a cord path is easier if you plan it before furniture arrives.

Verdict

Top pick: the TABYIK 35 oz, for the only stated sound figure and the lowest price tier, if your nursery is mildly damp. Budget-friendly with timers: the BeOkay 58 oz or the Newo 44 oz. Fewest refills: any of the three 95 oz models, ToLife, BEDRED or NineSky, with finish as the tiebreaker. Smallest room: the Windangel 44 oz.

Whichever you choose, read the manual, keep the cord and unit far beyond the crib’s reach, switch off the light, and add a separate hygrometer. A quiet room matters more than a long feature list.

Frequently asked questions

What humidity level is right for a nursery?

Commonly cited indoor comfort guidance sits at roughly 30 to 50 percent relative humidity, and that is the band most small dehumidifiers with a built-in humidistat are set around. This is general household guidance, not medical advice. Ask your pediatrician what they recommend for your baby and your climate, buy a separate digital hygrometer to place near the crib, and treat the dehumidifier’s own display as a rough guide only.

Is a dehumidifier safe to run in a baby’s room overnight?

Read the manual first, because the manufacturer’s instructions govern safe use. In general, look for auto shutoff when the tank fills, keep the unit upright on a hard, level surface, route the cord where no one can pull it, and keep the unit and its cord well out of the crib’s reach. The Editorial team has not used these units, so confirm each point on the listing and in the manual before running anything overnight.

How loud is a small dehumidifier?

Only the TABYIK title states a sound level, 28 dB, and the Editorial team cannot confirm that figure. Most other titles say quiet or low noise without a number. For a nursery, ask for the dB rating and the sleep-mode behavior in the listing, run the unit in a different room for a few hours first, and note whether a fan hum or a gurgle would disturb you. Buyer reviews often mention clicking and tank noises.

Should I avoid scented or color-light dehumidifiers in a nursery?

Skipping both is the cautious choice. Fragrance and aromatherapy features add airborne scent to a small room, and a bright color light can interfere with a dark sleeping space. Several listings here include 7-color or 10-color lights, so check whether the light can be turned off completely. Avoid any unit that advertises ozone output. If a feature is not listed, assume you cannot rely on it.

Does a bigger sq ft rating mean a better nursery dehumidifier?

No. Ratings of 1,000 sq ft in a listing title refer to the maximum space the maker claims the unit can serve, and a typical nursery is 100 to 200 sq ft. A bigger rating may mean a larger tank and fewer refills, but it can also mean a bigger footprint and a longer cord. Match the tank size and the noise controls to your routine, and treat the square footage as a ceiling, not a promise.