Buy the Levoit Core 300S for a bedroom or office under about 220 sq ft, and the Levoit Core 400S-P for a living room or large bedroom between roughly 220 and 360 sq ft. The 400S-P moves 64% more air (231 vs 141 CFM smoke CADR) but costs nearly twice as much to buy and about two-thirds more per filter, so measure the room and let the floor area decide.
The short answer
Choose the Core 300S if the room is a bedroom, nursery or home office up to about 220 sq ft, you want the purifier on a nightstand or desk, and you want the lower running cost of the two.
Choose the Core 400S-P if the room is 220 to 360 sq ft, the purifier has to stand on the floor in open space, or you cook, burn candles or get wildfire smoke and want headroom beyond what a small unit can give.
| On paper | Core 300S | Core 400S-P |
|---|---|---|
| Smoke CADR | 141 CFM | 231 CFM (AHAM Verifide; 240 dust, 259 pollen) |
| Room at 4.8 air changes/hr | ~219 sq ft | ~358 sq ft |
| Rated noise | 24 to 50 dB | 22 to 52 dB |
| Rated maximum power | 24 W | 38 W |
| Weight | 6 lb | 11 lb (10.8 in round, 20.5 in tall) |
| Filter | Core 300 filter, about $25–35 | Core 400S-RF, $49.99 list |
| Filter interval (Levoit) | 6 to 8 months | 6 to 8 months |
| App and auto mode | Yes | Yes, with a laser PM2.5 sensor |
| Ionizer | No | No |
| Typical price | $90–$110 | $160–$220 |
Where each one wins
The Core 300S wins on cost and size. At about $100 and 6 lb, it is the purifier you can put on a dresser without rearranging furniture. Its filter, an H13 True HEPA cylinder with carbon, costs about 40% less than the 400S-P's, and the unit draws no more than 24 W even at full speed. In a room it is sized for, it gives up nothing important.
The Core 400S-P wins on capacity and placement. It is AHAM-verified at 231 CFM for smoke, and its round 10.8 in base pulls air from every side, so it works standing in the middle of a living room rather than pushed against a wall. HouseFresh, testing the original Core 400S, measured just 8.51 W on speed 2. The filter bay also takes Levoit's Pet Allergy, Toxin Absorber and Smoke Remover cylinders ($59.99 to $64.99 at list) if odor is a bigger issue than dust.
Where does the room-size line fall?
Using this site's sizing rule (4.8 air changes per hour, 8 ft ceilings), the 300S suits about 219 sq ft and the 400S-P about 358. Here is what that means in real rooms, with each unit at full speed:
| Room | Core 300S | Core 400S-P |
|---|---|---|
| 10 x 12 home office (120 sq ft) | 8.8 changes/hr | 14.4 changes/hr |
| 12 x 18 bedroom (216 sq ft) | 4.9 | 8.0 |
| 14 x 20 primary bedroom (280 sq ft) | 3.8, undersized | 6.2 |
| 15 x 24 living room (360 sq ft) | 2.9, undersized | 4.8 |
| 20 x 25 open plan (500 sq ft) | 2.1 | 3.5, undersized |
The 220 to 360 sq ft band is where the 400S-P earns its price. Below it, the 300S is enough; above it, both fall short. High ceilings shift the line down: with 9 ft ceilings, the 300S tops out near 195 sq ft and the 400S-P near 318. The room size calculator handles odd shapes and vaulted rooms.
A bigger purifier in a smaller room has one quiet advantage: it can reach the same air-change rate on a lower fan setting. That is why some light sleepers put a 400S-P in a 200 sq ft bedroom. It works, but you pay for it in filters.
Three-year cost, side by side
Assumptions: middle of each unit's usual price range; the first filter comes in the box; Levoit's 6 to 8 month interval means a swap roughly every 7 months, or five replacements in three years. The lighter-use row stretches each filter to a year.
| Three years | Core 300S | Core 400S-P |
|---|---|---|
| Purchase | ~$100 | ~$190 |
| Filters, Levoit's schedule (5 swaps) | ~$150 | ~$250 |
| Filters, stretched to yearly (2 swaps) | ~$60 | ~$100 |
| Purchase + filters | $160–$250 | $290–$440 |
Electricity barely moves the result. Running 24/7 on speed 2 at $0.17/kWh, the 400S-P's measured 8.51 W comes to about $13 a year. Levoit publishes only the 300S's 24 W maximum; even flat out around the clock that is about $36 a year, and a bedroom setting draws well under it.
Per square foot actually cleaned, the two are closer than the sticker suggests: about $1.14 per sq ft for the 300S and $1.23 for the 400S-P on Levoit's filter schedule. The 400S-P's bigger bill buys a proportionally bigger room, not a premium badge. Try your own replacement interval in the filter cost calculator.
Differences buyers miss
The filters are not interchangeable. The Levoit Core 300 Replacement Filter fits only the Core 300 and 300S. The Levoit Core 400S Replacement Filter (Core 400S-RF) covers all four 400S variants, the PlasmaPro versions included. Neither fits the other, and neither fits the Core 600S. A drawer of spare 300 filters is no help after moving up.
"400S" and "400S-P" are the same machine. Levoit has documented no hardware change: same 38 W rating, same body, same filter. Older paperwork printed a single 260 CFM figure and 403 sq ft; the current AHAM-verified smoke rating is 231 CFM. If a listing quotes 403 sq ft, it is the old number, not a better unit.
PlasmaPro 400S is the one with the ionizer. Similar name, same filter, but it adds Levoit's ion output. Neither unit in this comparison has one.
Top speed sounds different. On paper the ranges are close, but HouseFresh measured the Core 400S at 60.3 dBA on its highest setting, against 43.2 dBA on speed 2. Plan on hearing it during a smoke event.
Pet hair loads both pre-filters. On each, the mesh is part of the filter cylinder: vacuum it, but it can't be rinsed and is thrown out with the filter. Heavy-shedding homes may get closer to six months than eight.
Already own a Core 300S?
Don't replace it; add to it. If the 300S sits in a bedroom under about 220 sq ft and doesn't spend its days on top speed, it is correctly sized and an upgrade buys nothing.
If you moved it into a living room and it now runs flat out all day, that's the sign it is undersized. Buy the 400S-P for that room and send the 300S back to a bedroom or office, where its spare filters still fit. Two Wi-Fi units also mean each room gets its own auto mode responding to its own air.
Which one to buy
Measure first. Under 220 sq ft, the Core 300S is the better value. Between 220 and 360 sq ft, the Core 400S-P is the right size, and its round body suits a mid-room spot.
If neither fits: for open spaces beyond about 360 sq ft, the Levoit Core 600S handles roughly 600 sq ft for $280 to $320, also with app control. If you want the 400S-P's room size without app features, the Coway Airmega AP-1512HH Mighty covers about 361 sq ft and its yearly filter set runs about $55–60, against roughly $85 a year for the 400S-P on Levoit's schedule. Homes with heavy shedders should look at the Levoit Vital 200S-P, whose pre-filter comes out and can be rinsed.
Frequently asked questions
Is a Core 400S-P overkill for a 200 sq ft bedroom?
Not overkill, but not necessary. A Core 300S already gives a 10 x 20 ft room about 5.3 air changes an hour flat out. The 400S-P would reach the same rate on a lower, quieter setting, which is the only real reason to pay about $90 more up front plus pricier filters.
Can two Core 300S units do the job of one Core 400S-P?
In separate rooms, yes, and often better. Together they deliver 282 CFM against 231, though in one open room they help only if placed at opposite ends. Over three years on Levoit's filter schedule, the pair costs roughly $500 against about $440 for a single 400S-P.
Does the Core 400S-P have an ionizer?
No, and neither does the Core 300S. The ionizer version is the PlasmaPro 400S (sometimes listed as PlasmaPro 400S-P), which uses the same filter and body. Check the name on the listing before buying if you want to avoid ion output.
Which Core is quieter, the 300S or the 400S-P?
Levoit rates the 300S at 24 to 50 dB and the 400S-P at 22 to 52 dB, so the larger unit has the lower floor and the louder top. HouseFresh measured the original Core 400S at 35.5 dBA in sleep mode and 60.3 dBA on its top speed. In a bedroom both are usually quiet enough; the 400S-P is the one that gets noticeably loud during a smoke event.
Will a Core 400S filter from the older model fit the Core 400S-P?
Yes. The Core 400S-RF is listed for the original 400S, the 400S-P and the two PlasmaPro 400S models, so stock bought for an older 400S still works. It will not fit a Core 300S or Core 600S.