Indoor air quality directly impacts your health. Whether battling allergies, managing asthma, or seeking cleaner air, choosing the right air purifier matters. Alen air purifiers combine powerful filtration with thoughtful design and exceptional support.
This best-air-purifiers.com review examines Alen’s flagship BreatheSmart series, exploring what sets these purifiers apart and whether they justify their premium pricing.
Three key benefits:
- Medical-grade H13 HEPA filtration capturing 99.9% of particles down to 0.1 microns (viruses, bacteria, dust, pollen, pet dander)
- Industry-leading lifetime warranty (Forever Guarantee) with filter subscription
- Customizable filter options for specific air purification needs—heavy smoke, pet odors, mold spores
Understanding Alen’s Air Purification Technology
Alen air purifiers use true HEPA air filtration with activated carbon to tackle particulate matter and gases. Every filter includes medical-grade H13 HEPA technology capturing particles down to 0.1 microns—exceeding standard HEPA requirements.
How HEPA Filtration Works
The true HEPA filter operates through interception, impaction, and diffusion mechanisms. This approach effectively removes allergens, dust, smoke, and viruses. Clean air delivery rate (CADR) determines purification speed—Alen’s ratings range from 190 CFM (BreatheSmart 35i) to 351 CFM (BreatheSmart 75i), suitable for rooms from 500 to 1,300 square feet.
Filter Options for Specific Air Purification Needs
Alen differentiates itself by offering four filter types for each BreatheSmart model:
HEPA-Pure: The entry-level filter focuses on dust, allergens, and basic particulates. Best for general air quality improvement in homes without specific air purification needs.
HEPA-Fresh: Adds 2.3-3.6 lbs of activated carbon to the H13 HEPA layer, targeting light odors and volatile organic compounds (VOCs) from household chemicals, cooking, and new furniture off-gassing.
HEPA-Silver: Incorporates an antimicrobial layer designed to neutralize mold spores, bacteria, and viruses. Ideal for bathrooms, basements, or humid climates where mold growth concerns exist.
HEPA-Odor/Heavy Smoke: The premium option containing maximum activated carbon (over 3.6 lbs in larger models) for serious odor challenges including cigarette smoke, wildfire smoke, strong cooking smells, and pet-filled homes.
| Filter Type | Carbon Content | Best For | Price Range |
|---|---|---|---|
| HEPA-Pure | Minimal | Basic dust/allergens | $69 |
| HEPA-Fresh | 2.3-3.6 lbs | Light odors, VOCs | $79-89 |
| HEPA-Silver | Antimicrobial | Mold, bacteria, viruses | $89-99 |
| HEPA-Odor | 3.6+ lbs | Heavy smoke, strong odors, pets | $99-119 |
“All Alen filters capture 99.9% of particles 0.1 micron or larger” – Alen official specifications. The choice between filter types doesn’t affect particle removal performance but significantly impacts gas and odor filtration capacity.
BreatheSmart Series: Model Comparison
Alen’s current lineup includes several BreatheSmart models designed for different room sizes and budgets. Each model’s clean air delivery rate (CADR) and coverage area determine its effectiveness for your space. Understanding the differences helps you select the right air purifier for your needs.
BreatheSmart 35i: Compact Efficiency
Coverage: 500 sq. ft. (2 air exchanges per hour)
CADR: 190 CFM
Noise Level: 26-49 dB
Dimensions: 17″ H x 17″ W x 9″ D
Price: ~$349
The 35i targets small to medium rooms like bedrooms, home offices, or nurseries. Despite its compact size, it delivers quiet operation at low speed settings, making it particularly suitable for nighttime use. The unit includes auto mode, smart app connectivity, and the same H13 HEPA technology as larger models.
BreatheSmart 45i: Mid-Size Powerhouse
Coverage: 800 sq. ft. (2 air exchanges per hour)
CADR: 208 CFM
Noise Level: 25-49 dB
Dimensions: 23″ H x 17.75″ W x 10.25″ D
Price: ~$419-428
The 45i represents Alen’s best price-to-performance ratio for most households. It handles living rooms, large master bedrooms, or open-concept spaces effectively. Features include optional ionizer function, laser sensor technology for accurate air quality detection, and customizable designer panels to match your decor.
BreatheSmart 75i: Maximum Coverage
Coverage: 1,300 sq. ft. (2 air exchanges per hour)
CADR: 351 CFM
Noise Level: 25-49 dB
Dimensions: 27″ H x 18.5″ W x 11.5″ D
Price: ~$799
Alen’s largest and most powerful air purifier excels in extra-large rooms, open floor plans, or high-traffic areas with children and pets. The 75i V2 model includes advanced features like improved laser sensors, comprehensive app functionality with scheduling, and the highest carbon capacity when paired with the Heavy Smoke filter.
BreatheSmart Flex: Budget-Friendly Option
Coverage: 700 sq. ft.
CADR: ~180 CFM
Price: ~$279-375
The Flex sacrifices smart features (no app support, auto mode, or ionizer) to achieve a lower price point while maintaining the same H13 HEPA filter quality. It suits cost-conscious buyers who prefer manual control and don’t need connectivity features.
| Model | Room Size | CADR | Smart Features | Ionizer | Price Range |
|---|---|---|---|---|---|
| 35i | 500 sq ft | 190 CFM | Yes | Yes | $349 |
| 45i | 800 sq ft | 208 CFM | Yes | Yes | $419-428 |
| 75i | 1,300 sq ft | 351 CFM | Yes | Yes | $799 |
| Flex | 700 sq ft | 180 CFM | No | No | $279-375 |
Key Features That Define Alen Air Purifiers
Smart Technology and Auto Mode
The BreatheSmart 35i, 45i, and 75i include intelligent air quality monitoring that automatically adjusts fan speed based on detected particulate levels. The laser sensor technology in newer models provides more accurate readings than traditional optical sensors found in competing air purifiers, requiring less frequent cleaning and delivering better PM2.5 detection.
When air quality deteriorates—from cooking, pets using litter boxes, or aerosol products—the purifier ramps up to higher fan speeds. Once air clears, it returns to energy-efficient low speed operation. “The purifier instantly detects and reacts to changes in air quality, which is both reassuring and fascinating” – verified user review from MindBodyDad.
The Alen Air app (available for 45i, 75i models) enables remote control, scheduling, and air quality monitoring. You can check PM2.5, tVOC, CO2, temperature, and humidity readings from anywhere, create automated schedules, and receive filter replacement notifications.
The color-coded LED ring provides visual feedback:
- Blue: Excellent air quality
- Green: Good air quality
- Yellow: Moderate air quality (purifier increases speed)
- Red: Poor air quality (purifier runs at highest speed)
Users can disable these indicator lights entirely with a double-press of the power button, useful for bedroom placement where light disrupts sleep.
Optional Ionizer Function
The ionizer generates negative ions that attach to airborne particles, making them heavier and easier to capture by the HEPA filter. However, ionizers can produce trace ozone as a byproduct, raising concerns for some users, especially those with respiratory conditions.
Should you use the ionizer on your Alen air purifier?
Independent testing shows the ionizer doesn’t significantly improve particle removal when the H13 HEPA filter already captures 99.9% of particles. “The ionizer function might be helpful for gases and odors, but according to our tests, it doesn’t seem to improve particle removal performance” – HouseFresh testing data.
Recommendation: Skip the ionizer for particle removal. If you experience persistent chemical odors or VOCs not resolved by the Fresh or Odor filters alone, try enabling it temporarily to see if it helps. Always prioritize proper ventilation and source removal for chemical exposure.
Whisper Quiet Operation
Alen emphasizes quiet performance across the BreatheSmart line. At the lowest setting, models operate around 25-26 dB—quieter than a whisper. Even at the highest speed, noise levels stay below 50 dB (about the volume of light rainfall).
The units generate pink noise rather than harsh white noise, creating a more pleasant sound profile. Many users report the higher fan speeds function effectively as white noise machines for better sleep while simultaneously cleaning bedroom air overnight.
Designer Panels and Aesthetics
Unlike many air purifiers that companies design as purely functional appliances, Alen treats their products as furniture. Each BreatheSmart model offers interchangeable front panels in colors including classic white, wood tones (warm oak), weathered gray, brushed stainless, graphite, and espresso.
This customization allows the air purifier to blend with your interior design rather than standing out as an eyesore. The rounded corners and clean lines enable placement against walls without sacrificing airflow performance.
Filter Life Indicator
The three-light filter life indicator eliminates guesswork about replacement timing:
- Green: Filter operating optimally
- Yellow: Filter nearing end of life (order replacement)
- Red: Filter needs immediate replacement
Newer models with RFID technology track actual filter usage and adjust the indicator based on runtime rather than just elapsed time. This smart tracking means you replace filters when actually needed, not on an arbitrary schedule.
Understanding Clean Air Delivery Rate (CADR)
Clean air delivery rate (CADR) measures removal speed for smoke, dust, and pollen in cubic feet per minute. The clean air delivery rate indicates an air purifier’s effectiveness—higher CADR ratings mean faster cleaning. Air purifiers with appropriate clean air delivery rate values for your room size provide optimal air purification. For effective air cleaning, aim for 4-5 complete air exchanges hourly. All BreatheSmart air purifiers exceed clean air delivery rate calculations for their rated room sizes, ensuring efficient particle removal at every fan speed.
Performance Analysis: What the Tests Show
Independent testing from Consumer Reports, HouseFresh, and Modern Castle validates Alen’s claims.
Modern Castle’s testing showed the 45i reduced PM2.5 to 0.1 ppm in two hours—below average. HouseFresh confirmed the 45i cleared their test room of all particulates in 30 minutes. The 75i V2 performed even faster with its 351 CFM CADR.
At 45 dBA fan speeds, Alen purifiers match competitor CADR while consuming less energy—approximately 45-50 watts on high speed, translating to $25-30 annual electricity costs on auto mode.
Build quality exceeds competitors. “The body is constructed of durable plastic and has a heavy base to prevent possible tipping” – Modern Castle. Units demonstrate longevity with users reporting 5+ years trouble-free operation.
The Forever Guarantee: Understanding Alen’s Warranty
Alen’s lifetime warranty differentiates it from competitors offering 1-5 year coverage. Requirements: register within 30 days and maintain filter subscription OR prove you used only genuine Alen filters.
The warranty covers all components except consumable filters for the purchaser’s lifetime—fan motor, control board, sensors, housing. Filter subscription provides 5% discount, automatic delivery, and warranty protection without saving receipts. Filters cost $69-$100+ depending on type, replaced every 9-12 months.
Replacement Filters: Cost and Longevity
Filter life spans 6-12 months depending on runtime, air quality, and filter type. Continuous 24/7 use, heavy smoke, or multiple pets reduce lifespan. Vacuum the pre-filter monthly and run on auto mode to extend life.
Red filter indicator or reduced airflow signals replacement time. Delayed replacement forces harder fan operation, shortening motor life and increasing energy use.
Can you wash Alen air filters? No. Water destroys HEPA filter structure. Always replace—never attempt cleaning beyond vacuuming the pre-filter.
Room-Specific Recommendations
Bedrooms: BreatheSmart 35i or 45i work best. Place 3-4 feet from bed at floor level, run on auto mode or low speed. Disable LED lights for uninterrupted sleep. Pink noise helps many sleep while filtering dust mites and pet dander. HEPA-Silver filter recommended for allergy sufferers.
Living Rooms: Large rooms need the 75i’s powerful coverage. Position centrally for maximum circulation. Open floor plans benefit from higher CADR to combat cooking odors. Heavy Smoke filter handles cooking smells better than basic options.
Homes with Pets: Pet dander, hair, and litter box odors require Fresh or Odor filters with substantial activated carbon. Place units where pets spend time. For multiple pets, the 75i with Heavy Smoke filter provides maximum filtration. “Having a dog who sheds like it’s her full time job and a boyfriend with allergies is a struggle, but this air purifier has helped tremendously” – Home Depot review.
Is an Alen Air Purifier Worth the Investment?
Alen occupies the premium segment—prices 30-50% higher than comparable models from Levoit, Winix, or Coway.
When Alen Makes Sense:
- Long-term reliability: Forever Guarantee eliminates replacement costs
- Aesthetics: Designer panels integrate into decor
- Specialized filtration: Heavy carbon filters for serious odors
- Quiet operation: Pink noise less intrusive than competitors
When Alternatives Might Be Better:
- Budget priority: Levoit and Coway offer solid performance at $150-300
- Smart home integration: Alen lacks Alexa/Google Home compatibility
- Maximum CADR per dollar: Winix 5500-2 delivers higher CADR at lower price
Five-Year Cost Comparison:
Alen 45i: $420 + $425 filters + $125 electricity = $970 total
Levoit Vital 200S: $190 + $250 filters + $150 electricity + $190 replacement = $780 total
The $190 difference ($3.17 monthly) represents a modest premium for build quality, aesthetics, and lifetime warranty.
Common Questions About Alen Air Purifiers
Where are Alen air purifiers made?
Alen designs in Austin, Texas but manufactures in China with quality control standards. All customer service and warranty support operates domestically.
How long do Alen air purifier filters last?
6-12 months depending on usage and air quality. Heavy smoking, multiple pets, or high dust requires 6-8 month replacement. Light use may extend to 12 months. RFID-equipped filters track runtime for accurate timing.
What does the color mean on Alen BreatheSmart?
LED colors indicate air quality: Blue (excellent), Green (good), Yellow (moderate), Red (poor). Helps identify when cooking, pets, or other activities affect air quality. Disable lights via double-press power button.
How do I reset the filter light on my Alen air purifier?
After installing new filter, press and hold filter reset button 5-10 seconds until lights turn green. Check your model’s manual for exact procedure.
Why is my Alen air purifier always red?
Indicates extremely poor air quality or saturated filter. Check filter first—replace if 6+ months old or visibly dirty. If new filter shows persistent red, investigate significant air quality problems (mold, smoking, excessive dust). Try unplugging 30 seconds to reset sensor. Contact Alen support if issues persist.
Does the Alen air purifier emit ozone?
With ionizer disabled, negligible ozone emissions well below EPA standards. HouseFresh testing confirmed no measurable ozone during normal operation. Ionizer enabled produces trace ozone within acceptable limits. Users concerned about ozone should disable ionizer—HEPA and carbon filtration remain highly effective.
Do HEPA air purifiers help with COVID?
H13 HEPA filters capture virus-sized particles including SARS-CoV-2 on respiratory droplets. Studies confirm air purifiers reduce viral concentrations indoors. However, they complement—not replace—vaccination, masking, and ventilation. Run continuously on auto/medium speed for best results. “All Alen filters capture 99.9% of particles 0.1 micron or larger” – including virus particles on droplets.
Is there a downside to air purifiers?
Air purifiers require ongoing filter costs, electricity, and generate some noise. They’re one component of air quality management—also need source control, ventilation, and regular cleaning. Don’t cure allergies or asthma, just reduce exposure. Running costs: $100-150 annually for filters and electricity.
Is the Alen 75i worth the money?
At $799, the 75i targets large spaces and serious air quality challenges with exceptional CADR, maximum carbon capacity, and lifetime warranty. Alternatives like Coway Airmega 400 or IQAir HealthPro offer similar coverage at varied prices. Worth it if you value designer aesthetics, American support, and lifetime coverage. Functional alternatives exist at lower prices for strictly performance-focused buyers.
Conclusion: Making Your Decision
Alen air purifiers excel in build quality, quiet operation, aesthetic customization, and lifetime warranty support. The BreatheSmart series offers models for every room size with H13 HEPA performance removing 99.9% of particles down to 0.1 microns.
Premium pricing reflects value for buyers prioritizing long-term reliability, low noise, and attractive design. The Forever Guarantee eliminates future replacement costs, potentially offsetting higher initial investment over 5-10 years.
Budget-conscious shoppers find comparable particle removal from less expensive brands. The decision hinges on priorities: Alen for lifetime support and aesthetics, competitors for lower upfront costs.
Improve your indoor air quality today. Assess room sizes, identify specific needs (allergies, pets, odors, smoke), and determine budget for purchase plus filters. Most households find the BreatheSmart 45i offers best coverage-features-value balance. Extra-large spaces or maximum odor challenges benefit from the 75i. Budget-minded buyers should consider Flex or 35i without sacrificing HEPA quality.
Clean air contributes to better sleep, reduced allergies, and improved health. Whether choosing Alen or another quality brand, effective air purification pays dividends through reduced respiratory irritation and comfortable living. Start breathing easier—your lungs will thank you.
Sources
- HouseFresh. “Alen BreatheSmart 45i review.” Independent air purifier testing laboratory. 2022.
- Modern Castle. “Alen Breathesmart 45i Review – 11 Real World Tests.” Performance testing data. 2024.
- Consumer Reports. “Alen BreatheSmart Classic Air Purifier Review.” Product testing and ratings. 2024.
- Alen Corporation. “BreatheSmart 75i HEPA Air Purifier.” Official product specifications and filter details. 2025.
- MindBodyDad. “Alen Breathesmart 75i vs. 45i vs. 35i: Which to Buy?” Long-term user experience review. 2025.
