The short answer
- Cheapest to own: the Levoit Core 400S, about $584 across five years.
- The Austin Air HealthMate costs the most to buy at $844 and still lands cheaper over five years than the Coway Airmega 400, which costs $390.
- Most expensive to own: the Alen BreatheSmart 75i, about $1,331, despite having the highest CADR here.
- Filters, not electricity, decide this. In five of the six, electricity is under a fifth of the bill.
We modelled six air purifiers over five years of ownership: purchase price, electricity at the US average of $0.17 per kWh running eight hours a day, and every filter the manufacturer says you need in that window. The order that produces is not the order of the price tags.
Every specification below comes from manufacturer documentation, retrieved on 31 August 2026, with the source printed next to each figure on the individual analysis pages. We have not physically tested any of these machines, and we say so on every page.
Our picks at a glance
#1 · rooms up to about 360 sq ft where the five-year cost is what decides it
Levoit Core 400S: the cheapest of these six to own, at $584 over five years
The cheapest to own of the six machines we have modelled: about $584 over five years. Levoit publishes the honest 4.8 ACH coverage figure on its own product page, which is rarer than it should be.
#2 · rooms up to about 360 sq ft, and anyone who wants an AHAM listing without paying for airflow they cannot use
Coway Airmega Mighty: one filter set, two different schedules
About $651 over five years, and the second cheapest to own here. Coway publishes the 4.8 ACH coverage itself, but sells one filter set containing two filters that expire six months apart.
#3 · rooms up to about 390 sq ft where you want more headroom than the Mighty and a single annual filter date
Coway Airmega 250: $89 filters put it $260 above the Mighty over five years
About $913 over five years. It cleans faster than the Mighty and costs $260 more to own, almost all of it in the $89 filter.
#4 · anyone who would rather buy once than subscribe, and who does not need a third-party cleaning rate to justify the price
Austin Air HealthMate: the dearest to buy, and $0 in filters across five years
The highest sticker price here, and still cheaper to own across five years than the Alen. The filter is rated for five years, so the consumables line is genuinely zero inside our window. There is no AHAM CADR listing to check the performance against.
#5 · rooms up to about 510 sq ft, where the filter bill matters more than the sticker price
Coway Airmega 400: the filters are 48% of what you pay over five years
Two thirds of what you pay arrives after the purchase. At $389.99 the five-year figure is $1,069, and $516 of that is filters.
#6 · large open rooms up to about 590 sq ft where you want the highest CADR here and will keep a filter subscription anyway
Alen BreatheSmart 75i: the lifetime warranty requires you to keep paying
The highest CADR here and the highest five-year cost, at about $1,331. The Forever Guarantee is real but conditional: it needs registration and an active filter subscription to stay in force.
Five-year cost, side by side
5-year cost, side by side
- Levoit Core 400S: the cheapest of these six to own, at $584 over five years$584sticker $190
- Coway Airmega Mighty: one filter set, two different schedules$651sticker $240
- Coway Airmega 250: $89 filters put it $260 above the Mighty over five years$913sticker $399
- Austin Air HealthMate: the dearest to buy, and $0 in filters across five years$1,049sticker $844
- Coway Airmega 400: the filters are 48% of what you pay over five years$1,069sticker $390
- Alen BreatheSmart 75i: the lifetime warranty requires you to keep paying$1,331sticker $799
The reordering
Sorted by what they cost in the shop, the six run: Levoit $190, Coway Mighty $240, Coway Airmega 400 $390, Coway Airmega 250 $399, Alen $799, Austin Air $844.
Sorted by what they cost to own for five years, they run: Levoit $584, Mighty $651, Airmega 250 $913, Austin Air $1,049, Airmega 400 $1,069, Alen $1,331.
Two machines change places by more than their price difference. The Austin Air HealthMate is the most expensive thing here to buy and finishes fourth, ahead of a machine that costs $454 less at the till, because its filter is rated for five years and our window is five years: nothing to replace, nothing to spend. The Coway Airmega 400 goes the other way, from third cheapest to buy to second dearest to own, because $516 of filters arrives after you have paid for it.
This is the whole reason this site exists. A price tag tells you what a machine costs on one day. It does not tell you what it costs to have.
What actually drives the number
Electricity is the line everyone optimises and it is almost never the one that matters. Across these six it runs from $94 to $205 over five years. The spread in filter costs is $0 to $516.
Three things move the filter line more than the filter’s price does:
- The interval, not the price. The Levoit filter is $49.99, the cheapest here, but it is due every nine months. That is six filters in five years rather than four, and it costs more in total than the Coway Mighty’s dearer set on an annual schedule.
- Whether the first one is in the box. All six ship with a filter fitted, which is why a five-year window contains four replacements on an annual schedule, not five. Costing it as five overstates every one of these totals.
- Whether the manufacturer gives you one interval or two. The Coway Mighty rates its HEPA filter at twelve months and its deodorisation filter at six, and sells them as a single set. Follow the shorter interval and its five-year total goes from $651 to over $870.
Coverage: the number on the box is not the number for your room
Manufacturers quote coverage at one or two air changes an hour. For allergy or smoke use the working figure is 4.8. The gap is not marginal: Coway advertises 1,560 square feet for the Airmega 400 and publishes 510 at 4.8.
Levoit and Coway both publish the 4.8 figure themselves, which is to their credit and made our work easier. For the Airmega 250 and the Alen we calculated it from the published CADR and showed the arithmetic. For the Austin Air we could not calculate it at all, and that is the next section.
The one we could not verify
How to read the recommendations
If the five-year bill is what decides it and your room is under about 360 square feet, the Levoit Core 400S is the answer, and it is not close. If you want an AHAM listing for all three particle types at a similar cost, the Coway Airmega Mighty is $67 more across five years.
For a large open room, the honest comparison is between the Alen BreatheSmart 75i at $1,331 and the Coway Airmega 400 at $1,069. The Alen cleans faster and carries a lifetime guarantee, but read its terms: it holds only with product registration and an active filter subscription.
And if you would simply rather buy once than subscribe, the Austin Air HealthMate is the machine that asks least of you after the purchase, on the condition that you accept a cleaning rate nobody independent has measured.
Frequently asked questions
Which air purifier is cheapest to own?
Of the six modelled here, the Levoit Core 400S, at about $584 across five years: $190 to buy, $94 in electricity and about $300 in filters.
Is a more expensive air purifier cheaper in the long run?
Sometimes, and it depends entirely on the filter. The Austin Air HealthMate costs $844, more than anything else here, and costs less over five years than the $390 Coway Airmega 400, because its filter is rated for five years.
Do air purifiers use much electricity?
Less than people expect. Across these six, five years of electricity runs from $94 to $205, while filters run from nothing to $516.
How did you calculate these figures?
Purchase price, plus electricity at $0.17 per kWh for eight hours a day, plus every filter the manufacturer says you need in five years, counting the one in the box. The source for each specification is printed on the individual analysis pages.
Did you test these air purifiers?
No. We are a research publication, not a lab. We verify manufacturer and third-party documentation, publish the source next to every number, and calculate the costs that are left out of the price tag.
