Alen® air purifiers are engineered to outperform by combining power with efficacy and superb filtration technology. And our beautifully designed, whisper-quiet units do it without disrupting your conversations or your lifestyle. We don’t all know how loud decibels are and what some people consider loud, others may not. That’s why we take videos of all the air purifiers we review, recording each unit at their different fan speeds. Both units come with an AQI (Air Quality Indicator) color wheel in the center of the control panel. Using data provided by the air purifier sensors, this light displays the air quality in your room using five colors.
We then turn the air purifier on at full fan speed to see how long it takes them to remove all the contaminants from the room. Sometimes, you’ll find that air purifiers with touch-sensitive controls Lasko Box Fan are lacking on the “sensitive” part, making them hard to operate. From the units we’ve reviewed, we found the controls very easy to press, and little force is needed to activate them.
Space inside the filter gets smaller as more and more pollutants become trapped, making the filter less effective. Both units performed well in our performance testing room, with the 45i clearing all of our simulated contaminants from the air in 33 minutes and the Flex in 34 minutes. If you’ve read a review on HouseFresh before, you’ll know that we test every air quality product we recommend in our own home lab. The 45i may have been faster by one minute, but the Flex has a lower CADR, so it worked much harder to get its result.
For an air purifier of this size and cost, we expected to see these two units give us a time of around 30 minutes, but we didn’t predict the difference to be so minimal. What differentiates these two air purifiers from many other models is that you can choose from five different variations of H13 HEPA filters to customize your unit to your needs and wants. As the 45i and Flex were so similar in size, we wanted to pit them against each other. This guide compares their test results, specifications, design, controls, filters, performance, sound and running costs to see which unit best suits your needs and budget. Known for their simple yet elegant designs and heavy-duty filters, Alen air purifiers are extremely popular and trusted throughout the world.
The technology inside these two units may differ, but looking at them side-by-side, you’ll see they are practically exactly the same. When it comes to specifications, the 45i is the winner as it’s lighter, quieter and, due to its higher CADR, tackles pollutants in larger rooms than the Flex. In 2024, however, the Classic model is far surpassed by the superior Alen BreatheSmart 75i model; the best-of-the-best air purifier in general, not only among Alen Air purifiers. This is quite a lot; comparatively, as we have discussed in the Alen BreatheSmart 75i review, that air purifier generates only 25 dB at Speed 1.
This unbeatable combination allows for whisper quiet removal of particulate matter, even on the highest setting, 24/7. The biggest difference between the features on the 45i and Flex is that the 45i comes with an auto mode. This uses the same air quality information from its sensor to adjunct the fan to suit the amount lasko pedestal fans of pollutants in the air. The cost of replacement filters is the true cost of any air purifier. Some companies do have a ridiculously low price of the air purifier itself because they earn money on the replacement filters. This indicates at what fan speed setting you should run the Classic large air purifier.
Alen® 45i Air Purifier’s powerful, high-speed fans continuously move air through True HEPA 13, medical grade filters to produce ideal conditions for better sleep. Experience non-stop protection from irritants that can affect sleep quality with our beautiful, quiet, best-selling, bedroom buddy. The Alen® FLEX is the ultimate purifier for the kid’s room, guest room, home office or home gym.
The one problem that the Classic model successor – the Alen BreatheSmart 75i – solved is the energy-efficiency. Due to larger coverage, Alen BreatheSmart is considered a large room air purifier. Smaller original Alen BreatheSmart series models – FLEX and FIT50 – are outmatched by the new Alen BreatheSmart 45i model (with 245 CADR rating). It’s the biggest of the 3 original Alen BreatheSmart models, most appropriate for large rooms. Models that have the Energy Star rating will use less energy than comparable products. Match your unit to your personal style with one of our designer panels.
All of these controls are mirrored in the Alen Air mobile app, which can be used to remotely control the 75i and to monitor your air quality in greater detail. The setup process seems more streamlined than the last time we tested this product and took just a couple of minutes to complete. Now with an updated app, the BreatheSmart 75i provides plenty of power and air quality info, but its size and price tag are more suited to commercial settings than home environments. Through our performance testing, we were impressed with all the filters from the Alen products we reviewed.