Best Alen Air Purifiers

Why this brand page is shaped differently from the other five

We have now done this exercise for Levoit, Blueair, Coway, Winix, Honeywell and Medify. Each time the question was which machine to buy, and the answer came out of the ENERGY STAR certified database.

Alen breaks that pattern, because the machine is only half of what you are choosing. Each of its three certified purifiers is sold with one of three filters, and the filter decides what the unit removes:

Read the last two columns together, because this is the part that costs money quietly. The carbon filters are more expensive to buy and shorter-lived - roughly 7 to 10 months against 12 to 15 for the particle-only version. So choosing Ultimate over Essential is not a one-time premium; it is a higher price on a faster cycle, repeating for as long as you own the machine.

Which makes the question worth asking honestly: is your problem a gas? If it is dust, dander and pollen, the particle-only filter is the correct purchase and the cheapest one. If it is cooking smells, smoke or a musty room, you need the carbon and you should expect to pay for it on a schedule. Our activated carbon page is the background on why there is no way around that trade.

The three certified machines

Same method as every other brand page here: every row Alen has in the ENERGY STAR certified room air cleaners database, ranked on the figures that database publishes.

Two things in that table are worth pulling out. The 75i at 7.12 CFM/W is genuinely competitive - higher than any certified Winix (best 6.26) or Medify (best 6.10), and within a few percent of the best Honeywell at 7.39. That is a real difference from the last two brand pages we wrote, where the whole range was weak.

And the 45i is not in the database at all - Alen's best-known model, on sale and widely recommended, with no certified efficiency, annual energy or ozone figure. That is now the fourth brand in a row where the famous model is the uncertified one, after Winix's 5500-2 line, Honeywell's HPA300 and Medify's MA-112. It is the rule in this category rather than the exception.

Where Alen is unusually straight, and where it is not

It is worth giving credit precisely. On the 75i, Alen publishes CADR per fan speed - 100, 185, 255 and 300 CFM on speeds one to four, and 375 on Turbo - plus a wattage range of 1.36 to 55 W and a noise range of 25 to 51 dBA. Very little of this category publishes per-speed figures at all, and they are what let you work out what the machine will actually cost you at the setting you use.

Better still, its ozone figures agree between the two sources. Alen states “0 PPM when disengaged, less than 0.001 PPM with ionizer engaged”. One thousandth of a part per million is one part per billion, which is exactly the 1.00 ppb the certification reports for the 75i. On Winix and Medify those two numbers disagreed and we had to report both; here they corroborate each other, and they also tell you the non-zero figure is the ionizer rather than the machine.

Three places it is less straight:

• The filter grade. All three certified Alens are filed as HEPA-Type. Alen describes the media as True HEPA and medical-grade, and separately claims “99.9% of particles greater than 0.1 micron” - which is not the 99.97%-at-0.3-micron True HEPA standard either. That is three descriptions of one filter, all Alen’s, and it is the same pattern as Medify. What the words mean is on HEPA filters explained.
• The coverage claim. “Up to 2,800 sq ft every hour” for the 75i, with no air-change rate stated anywhere. The certified figure at the rate that matters is 574 sq ft - about a fifth. The CADR page explains why the bigger number exists.
• The warranty. Alen calls it a “Forever Guarantee”, a “Lifetime Warranty” and a “Lifetime Guarantee” on the same page, and the one piece of fine print attached to it is the important bit: it requires product registration and an active air filter subscription. A lifetime warranty you keep by subscribing is a subscription.

The thing we have to say about price

Alen is the most expensive brand on this site by a wide margin, and the certified data does not justify it on clean air alone. The 75i delivers 370 CFM over 574 sq ft; the Coway Airmega 350 delivers 360 CFM over 558 sq ft at zero ozone for a fraction of the outlay, and the Levoit Core 600S does 391 CFM over 606 sq ft. If your decision is clean air per dollar, this is not the brand and we are not going to pretend otherwise on its own page.

What you are paying for, if you choose to, is the filter system - a genuine three-way choice between particle-only, carbon, and carbon-plus-catalyst on the same chassis, with published filter lives for each. No other brand here lets you match the media to the symptom that way, and for a household whose problem is specifically odors or VOCs rather than dust, that is a real thing to be buying rather than a marketing story.

How we ranked

1. Can it be bought? All three certified models can, in all three filter versions - which on this brand is unusual, since the last four brand pages all had certified models we could not find on sale.
2. Certified smoke CADR and the room it honestly covers at 4.8 air changes per hour, not the headline figure.
3. Certified clean air per watt and annual energy.
4. Certified ozone, which separates the 75i from the other two.
5. Filter match. Unique to this brand, and the reason our middle pick is a specific filter version rather than just a model.

We have not tested any of these units. Every figure is from the certified database or from Alen’s own published specification, and each spec row says which.

What we would actually buy

The 25i with the Essential filter, if you want to try the brand without committing several hundred dollars. 97 CFM over a certified 150 sq ft is a bedroom machine, it reports zero ozone, it costs about $17 a year to run, and the Essential filter is both the cheapest and the longest-lived of the three. Buy it for the size and the filter life, not for the Most Efficient badge it happens to carry.

The 35i with the Ultimate filter, if the problem is smells rather than dust. This is the configuration that demonstrates the brand’s actual argument: a carbon-and-catalyst stage on a 233 sq ft certified machine at zero ozone, for the household whose complaint is a musty room or cooking that travels. Accept that this filter is the priciest and the shortest-lived, and that the same 35i costs meaningfully less with the particle-only filter if gases are not your issue.

The 75i with the Essential filter, for a large or open-plan room. It is the most clean air Alen certifies, the only Alen that is competitive on efficiency, and the Essential version saves you a three-figure sum against the Ultimate on an identical purifier. The two things to weigh: it is the only certified Alen with non-zero ozone, at 1.00 ppb from its ionizer, which Alen says falls to zero when the ionizer is disengaged - and it is a lot of money for clean air you can buy more cheaply elsewhere.

Not the 45i, however well reviewed it is elsewhere. It is not in the certified database, so there is no certified CADR, no annual energy figure and no ozone figure for it - and on a machine at this price, buying without those is a choice we would not make. It is named here for completeness rather than recommended.