Alen BreatheSmart Air Purifiers: Which Size Fits Your Room

By Simone Ellery · Updated 2026-09-20T21:05:09.517Z · How we choose · How we make money

We may earn a commission if you buy through links on this page, at no extra cost to you. Our picks are based on the data shown, not on what pays us.

BreatheSmart 35i

$289.00 tracking this price since yesterday · 2 readings

Pros

• Four fan settings from 66 CFM up to a 190 CFM Turbo mode
• Rated 4.8
• Costs $289.00, the lowest current price of the three BreatheSmart models

Cons

• At 190 CFM Turbo it moves less air than the 45i's 255 CFM top speed
• Costs $160.00 less than the 45i and $510.00 less than the 75i, so it is the smallest-capacity option here

Who it's for: Anyone who wants a compact Alen BreatheSmart purifier at the lowest current price in the lineup.

Check price at alen.com

BreatheSmart 45i

$449.00 tracking this price since yesterday · 2 readings

Pros

• Four speeds plus a top speed of 255 CFM, the middle option between the 35i's 190 CFM turbo and the 75i's 375 CFM turbo
• Rated 4.8
• Costs $350.00 less than the BreatheSmart 75i

Cons

• At $449.00 it costs $160.00 more than the BreatheSmart 35i
• Lower top airflow than the BreatheSmart 75i's 375 CFM turbo

Who it's for: Anyone who wants more airflow than the BreatheSmart 35i but doesn't need the BreatheSmart 75i's 375 CFM turbo.

Check price at alen.com

BreatheSmart 75i

$799.00 tracking this price since yesterday · 2 readings

Pros

• Highest airflow in the lineup: 375 CFM on Turbo, with 300 CFM on Speed 4 and 255 CFM on Speed 3
• Top rating of the three at 4.9
• Four speeds plus Turbo, from 100 CFM on Speed 1 up to 375 CFM

Cons

• Priciest of the three at $799.00
• Costs $350.00 more than the BreatheSmart 45i and $510.00 more than the BreatheSmart 35i

Who it's for: Buyers who want the most powerful and highest-rated of these Alen BreatheSmart purifiers and will pay $799.00 for it.

Check price at alen.com

How we chose

We compared the three BreatheSmart models on airflow at each speed, price, and reader ratings. The 35i starts at 66 CFM on Speed 1 and reaches 190 CFM on Turbo, at $289.00 with a 4.8 rating. The 45i moves 80 CFM on Speed 1 and 255 CFM on Speed 4, at $449.00 with a 4.8 rating. The 75i runs 100 CFM on Speed 1, 300 CFM on Speed 4, and 375 CFM on Turbo, at $799.00 with a 4.9 rating.

Price separates them clearly. The 45i costs $160.00 more than the 35i, and the 75i costs $510.00 more than the 35i and $350.00 more than the 45i. Ratings are close across the family: 4.8 for the 35i and 45i, 4.9 for the 75i.

Airflow at each speed is where the models diverge most. The 75i leads at every speed it shares with the others, and it is the only one with a Turbo setting at 375 CFM. The 45i sits between the two, with a Speed 4 of 255 CFM. The 35i has the lowest airflow at each of its speeds.

Who should skip these

Skip the BreatheSmart 35i, 45i, and 75i if you need coverage beyond a whole floor. The 75i tops out at 375 CFM on Turbo, the 45i at 255 CFM on Speed 4, and the 35i at 190 CFM on Turbo. That is the ceiling for this family.

Skip them too if published price history matters to you. All three carry current prices — $289.00 for the 35i, $449.00 for the 45i, $799.00 for the 75i — and none of that gives you a range, a low, or a high to compare against.

If budget is the deciding factor, the gaps are wide: the 45i costs $160.00 more than the 35i, the 75i costs $510.00 more than the 35i, and the 75i costs $350.00 more than the 45i. Ratings sit at 4.8 for the 35i and 45i and 4.9 for the 75i, so the differences here are coverage and price, not reception.

How to choose the right one

Match the top CFM figure to the room you need to cover. The BreatheSmart 35i reaches 190 CFM on Turbo, which suits a bedroom. The BreatheSmart 45i reaches 255 CFM at Speed 4, which suits a living area. The BreatheSmart 75i reaches 375 CFM on Turbo, which suits a whole floor.

Price is the other lever. The 35i is $289.00, the 45i is $449.00, and the 75i is $799.00. The 45i costs $160.00 more than the 35i, the 75i costs $510.00 more than the 35i, and the 75i costs $350.00 more than the 45i. Ratings sit close together: 4.8 for the 35i, 4.8 for the 45i, and 4.9 for the 75i.

If a bedroom is the job, the 35i covers it at the lowest price. If you want more mid-size headroom, the 45i steps up for $160.00 more. For a whole floor, the 75i is the one that reaches 375 CFM.

Questions readers ask

By Simone Ellery · Published 2026-09-22