Updated August 2026: rebuilt this comparison around filter costs instead of specs — added a sourced, itemized annual filter-cost table for each machine and a 5-year total-ownership breakdown.
The real cost of owning one of these three purifiers isn’t the sticker price — it’s what you keep buying afterward. The Levoit Core 400S (~$180) has the cheapest single filter of the three (~$50/year) but its filters alone cost more than the machine itself within about three and a half years. The Coway Airmega 400S (~$749) has the most expensive annual filter bill (~$99/year) but also the longest warranty. The Blueair Blue Pure 311i Max (~$230) needs filters most often — every 9 months instead of 12 — which pushes its yearly filter cost above the Levoit’s despite a similar sticker price.
What You Pay Once: The Machine
Sticker price spans a wide range across these three — from $180 to $749 — and that gap is mostly explained by rated coverage, not brand markup. Here’s what each one costs to buy and how long the manufacturer stands behind it:
| Purifier | Price | Rated coverage | Warranty |
|---|---|---|---|
| Levoit Core 400S | $180 | 403 sq ft | 2 years, per Levoit’s own warranty policy |
| Coway Airmega 400S | $749, per Coway’s official store | 3,100 sq ft | 5 years, per Amazon’s product listing for the 400S |
| Blueair Blue Pure 311i Max | $230, per Target’s current listing | 1,858 sq ft | 1 year standard, extendable to 3 years by registering, per Blueair’s site |
Prices are approximate, current as of publication, and change frequently — confirm the latest price with the retailer before buying.
What You Pay Every Year: Filters
This is the number that actually separates these three over time, because the purchase price is a one-time cost and the filter isn’t. Each brand publishes its own filter price and recommended replacement interval — here’s what that works out to per year:
| Purifier | Filter price | Replacement interval | Filters per year | Annual filter cost |
|---|---|---|---|---|
| Levoit Core 400S | $49.99, per Levoit’s own store | ~12 months, per Levoit’s current US manual | 1.0 | ~$50 |
| Coway Airmega 400S | $99.27 for the 2-piece Max2 filter set, per Walmart’s current listing | ~12 months for the set, per the product listing | 1.0 set | ~$99 |
| Blueair Blue Pure 311i Max | $44.99, per Blueair’s own store | up to 9 months, per Blueair’s own filter-life guidance | ~1.33 | ~$60 |
The Levoit has the cheapest single filter of the three by a wide margin, but the Coway’s filter set costs almost exactly double the Levoit’s per year — the tradeoff for a filter surface area built to cover 3,100 sq ft instead of 403. The Blueair’s per-filter price actually sits below the Levoit’s, but because Blueair rates it for as little as 9 months of use instead of 12, replacing it more often erases that advantage and pushes its annual cost above the Levoit’s.
What Five Years Actually Costs
Stretch the filter math out over five years — a realistic ownership span for any of these three — and the picture shifts again. Here’s purchase price plus five years of filters, added up:
| Purifier | Purchase price | 5-year filter cost | 5-year total | Per-year average |
|---|---|---|---|---|
| Levoit Core 400S | $180 | ~$250 (5 × $49.99) | ~$430 | ~$86/year |
| Blueair Blue Pure 311i Max | $230 | ~$300 (5 × ~$60) | ~$530 | ~$106/year |
| Coway Airmega 400S | $749 | ~$496 (5 × $99.27) | ~$1,245 | ~$249/year |
The Levoit stays the cheapest of the three even after five years of filters — but its filter spend alone (~$250) actually exceeds the machine’s own $180 purchase price within that window, which isn’t obvious from the sticker price alone. The Coway’s per-year average runs roughly triple the Levoit’s, but if 3,100 sq ft of actual coverage is what you need, none of the cheaper options gets you there — you’d need multiple smaller units instead, which brings its own multiplied filter cost. The Blueair lands in the middle on both counts, with the added tradeoff of the most frequent filter swaps of the three.
So Which One Is Worth the Filter Bill?
For a single bedroom or small living room, the Levoit Core 400S wins on both purchase price and five-year total — just budget for filters costing more than the machine did, over time. For a large, open floor plan where 3,100 sq ft of coverage is a real requirement rather than a nice-to-have, the Coway’s higher filter bill is the cost of not needing several smaller units instead. The Blueair fits families who want a quieter unit and mid-size coverage and are willing to swap filters a bit more often to get it.
FAQ
How much should I budget per year just for filters?
Budget roughly $50/year for the Levoit Core 400S, $99/year for the Coway Airmega 400S, and $60/year for the Blueair Blue Pure 311i Max, based on each manufacturer’s own filter price and replacement interval.
Does a cheaper purifier always mean cheaper filters?
No — the Levoit costs the least upfront, but its filters, replaced yearly, add up to more than the machine’s own purchase price within about three and a half years, so sticker price alone doesn’t predict total cost.
Can I stretch a filter past its rated replacement interval?
You can, but performance drops as a filter loads with particles, and running a HEPA or electrostatic filter well past its rated life reduces how much it’s actually capturing, per each brand’s own replacement guidance.
Which of these three has the cheapest long-term ownership cost?
The Levoit Core 400S has the lowest 5-year total at roughly $430 including filters, but it’s also rated for the smallest space at 403 sq ft, so the comparison only holds if that coverage is actually enough for your room.
Do washable pre-filters cut down on the cost?
Partly — the Blueair’s cloth pre-filter is washable and reusable rather than a recurring purchase, but the main particle-and-carbon filter behind it still needs periodic replacement regardless of how well the pre-filter is maintained.
How We Compared These
We built the filter-cost figures above from each manufacturer’s own current filter pricing and published replacement guidance — Levoit’s official store and US manual, Walmart’s current listing for Coway’s Max2 filter set, and Blueair’s own filter-life guidance and store pricing — not from a single aggregator or a third-party estimate. Purchase prices, coverage ratings, and warranty terms come from each brand’s own store or current major-retailer listing. We did not run our own lab testing or long-term filter-wear testing — this is a comparison of published pricing and manufacturer-stated intervals, not hands-on use. Read our full editorial standards.
