OVERALL

SPECS

VS AVERAGE

REVIEWS

ALTERNATIVES

Alen 45i Pure Carbon Review | 46 Data compared

Avg. price in UK: ~£380
Avg. price in US: ~$490
Max. CADR: 245 m³/h
Maximum room area: 74 m²
Maximum noise level: 49 dB
HEPA filter: yes
Weight: 6.8 kg

Alen 45i Pure Carbon review. Compare 46 technical specifications and user reviews to see how this product ranks in the Air Purifiers category and whether it is worth buying.

7.4

Very good

6.9

Good

9.3

Exceptional

6.9
Bedroom use
Score components:
35.0%
5.8
Maximum noise level
30.0%
10
Night mode
20.0%
6.2
Maximum room area
15.0%
4.3
Weight
6.6
Allergy relief
Score components:
35.0%
5.4
Max. CADR
30.0%
10
HEPA filter
20.0%
5.5
Number of filtration stages
15.0%
4.0
Washable prefilter
7.7
Smoke removal
Score components:
35.0%
10
Activated carbon filter
30.0%
5.4
Max. CADR
20.0%
5.5
Number of filtration stages
15.0%
10
Air quality indicator

Best prices in UK

Best rankings

#45 in Best Air Purifiers for Smoke
#45 in Best Air Purifiers with HEPA Filters
#46 in Best Air Purifiers for Mold
#47 in Best Air Purifiers
#47 in Best Air Purifiers for Pets
#51 in Best Air Purifiers for Bedrooms
#79 in Best Air Purifiers for Dust

Verdict

The Alen BreatheSmart 45i with the Pure filter is a premium air purifier featuring a Clean Air Delivery Rate (CADR) of 255 CFM, designed to circulate air efficiently in spaces up to 800 square feet every 30 minutes. It features a medical-grade H13 True HEPA filtration system that removes 99.9% of airborne particles down to 0.1 microns, an ozone-free ionizer, and an intelligent laser sensor with a 5-color real-time air quality indicator light ring that drives its automated fan speed adjustments across 4 power settings (drawing between 1.1 to 50 watts). Key advantages include its ultra-quiet WhisperMax technology that generates soothing pink noise from 23 to 49 dB, a lifetime warranty with an active filter subscription, Energy Star certification, and a compact 15-pound frame with customizable front panels. However, the standard Pure filter configuration lacks a pelleted carbon element needed to neutralize volatile organic compounds (VOCs) and persistent odors, filter replacements can be relatively expensive, and the unit lacks a detailed numerical particle counter display on its panel.

Technical Specifications of air purifier Alen 45i Pure Carbon

Overall score

7.4

Show more

Hide

Popularity

What it is: An indicator based on the number of reviews received by products in the Air Purifiers category.

When it matters: When you prefer products in the Air Purifiers category that have been chosen and reviewed by many other buyers.

Performance

6.3

Show more

Hide

Power

What it is: The electrical power consumption of the air purifier during operation, measured in watts (W).

When it matters: Helpful for estimating long-term electricity costs, particularly when running the unit continuously day and night.

Importance: HIGH

Max. CADR

What it is: The Clean Air Delivery Rate (CADR), measuring the volume of purified air delivered per hour in cubic metres.

When it matters: Crucial for determining how rapidly the purifier circulates and cleans room air, especially for severe allergies or larger spaces.

Importance: HIGH

Maximum room area

What it is: The maximum recommended floor area (in square metres) that the air purifier can effectively treat.

When it matters: Essential for matching the purifier's airflow capacity to your room size so all air is filtered thoroughly.

Importance: HIGH

N. of speeds

What it is: The number of manual airflow speed levels available to choose on the air purifier.

When it matters: Provides flexible control between whisper-quiet low speeds for sleeping and powerful high speeds for fast room clearing.

Importance: MEDIUM

Maximum noise level

What it is: The sound level emitted by the air purifier when running at its highest fan speed, measured in decibels (dB).

When it matters: Important if you plan to use the purifier in bedrooms, nurseries, or home offices where loud fan noise causes disturbance.

Importance: HIGH

Show more

Features

7.9

Show more

Hide

Air quality indicator

What it is: An optical or laser sensor system displaying real-time indoor pollution levels via color rings or numerical values.

When it matters: Provides immediate visual feedback on air cleanliness and confirms that the purifier is working effectively.

Importance: MEDIUM

Continuous purification

What it is: Engineered motor and filter architecture designed for safe, uninterrupted 24/7 operation without thermal degradation.

When it matters: Essential for maintaining permanently low allergen and dust concentrations in polluted urban areas or high-pollen seasons.

Importance: LOW

Auto mode

What it is: An intelligent operating mode that automatically increases or decreases fan speed based on live sensor pollution readings.

When it matters: Maximizes convenience and saves electricity by running quietly on low speed and ramping up only when pollution is detected.

Importance: MEDIUM

Timer

What it is: A programmable shut-off countdown timer that turns off the air purifier automatically after a set number of hours.

When it matters: Convenient for running the unit for a specific duration before leaving home or going to bed without wasting electricity.

Importance: LOW

Maximum timer

What it is: The longest selectable countdown duration available on the air purifier's timer, expressed in hours.

When it matters: Relevant if you prefer setting extended automated operating cycles, such as a full 8-hour workday or 12-hour overnight window.

Importance: LOW

N/A

Show more

Design

6.2

Show more

Hide

Color

What it is: The primary exterior color and aesthetic finish of the air purifier housing.

When it matters: Important for ensuring the appliance blends harmoniously into your room decor and furniture style.

Importance: LOW

grey

Material

What it is: The primary manufacturing material used for the outer casing, such as ABS plastic, polycarbonate, or aluminum.

When it matters: Influences structural rigidity, scratch resistance, premium appearance, and ease of wiping clean.

Importance: LOW

fiberglass

Display

What it is: An integrated digital screen showing active fan speed, particulate pollution numbers, filter health, and active timers.

When it matters: Enables quick visual checks of air metrics and purifier settings directly on the device without picking up your phone.

Importance: LOW

Display position

What it is: The physical placement of the display screen on the body of the air purifier (e.g., top panel or front facade).

When it matters: Affects viewing convenience: top displays are easiest to read while standing, while front displays are visible from across the room.

Importance: LOW

top

Control type

What it is: The user interface mechanism for operating the device, such as capacitive touch keys, push buttons, or rotary dials.

When it matters: Determines tactile responsiveness, ease of operation in dark rooms, and durability over years of regular use.

Importance: LOW

touch

Show more

Alen 45i Pure Carbon vs the average air purifier

Why is Alen 45i Pure Carbon better than the average air purifier?

Show more

Hide

Higher Manufacturer warranty
Alen 45i Pure Carbon offers higher Manufacturer warranty than the average air purifier (99 years vs $$$).
Lifetime coverage requires an active filter subscription.
What it is: This attribute shows the air purifier's manufacturer warranty.
When it matters: It matters if longer manufacturer coverage is important to you.
Importance: MEDIUM
Alen 45i Pure Carbon offers higher Manufacturer warranty than the average air purifier (99 years vs $$$).99 years vs 2 years
Has a child lock
Alen 45i Pure Carbon has a child lock; the average air purifier does not.
What it is: A safety lock feature that disables the on-device control panel buttons to prevent unintended changes.
When it matters: Essential in households with curious toddlers or pets who might accidentally switch off the purifier or alter speed settings.
Importance: MEDIUM
Alen 45i Pure Carbon has a child lock; the average air purifier does not.
25 m² larger room area
Alen 45i Pure Carbon covers a larger room area than the average air purifier (74 m² vs 49 m²).
What it is: The maximum recommended floor area (in square metres) that the air purifier can effectively treat.
When it matters: Essential for matching the purifier's airflow capacity to your room size so all air is filtered thoroughly.
Importance: HIGH
Alen 45i Pure Carbon covers a larger room area than the average air purifier (74 m² vs 49 m²).74 m² vs 49 m²
1 more fan speeds
Alen 45i Pure Carbon provides more fan speed settings than the average air purifier (4 vs 3).
What it is: The number of manual airflow speed levels available to choose on the air purifier.
When it matters: Provides flexible control between whisper-quiet low speeds for sleeping and powerful high speeds for fast room clearing.
Importance: MEDIUM
Alen 45i Pure Carbon provides more fan speed settings than the average air purifier (4 vs 3).4 vs 3
4 dB lower maximum noise level
Alen 45i Pure Carbon runs quieter at maximum speed than the average air purifier (49 dB vs 53 dB).
What it is: The sound level emitted by the air purifier when running at its highest fan speed, measured in decibels (dB).
When it matters: Important if you plan to use the purifier in bedrooms, nurseries, or home offices where loud fan noise causes disturbance.
Importance: HIGH
Alen 45i Pure Carbon runs quieter at maximum speed than the average air purifier (49 dB vs 53 dB).49 dB vs 53 dB
Has an ionizer
Alen 45i Pure Carbon has an ionizer; the average air purifier does not.
What it is: An auxiliary electronic feature releasing negative ions that attach to airborne particles, causing them to clump and settle faster.
When it matters: Acts as a supplementary cleaning boost for fine dust, though buyers sensitive to ozone should ensure it can be toggled off.
Importance: LOW
Alen 45i Pure Carbon has an ionizer; the average air purifier does not.
0.5 m longer power cord
Alen 45i Pure Carbon features a longer power cord than the average air purifier (2.3 m vs 1.8 m).
What it is: The total physical reach of the supplied electrical power cord, measured in metres (m).
When it matters: Determines optimal placement flexibility relative to wall power outlets without needing extension cables.
Importance: LOW
Alen 45i Pure Carbon features a longer power cord than the average air purifier (2.3 m vs 1.8 m).2.3 m vs 1.8 m
12.5 W higher power
Alen 45i Pure Carbon has a higher power output than the average air purifier (50 W vs 37.5 W).
What it is: The electrical power consumption of the air purifier during operation, measured in watts (W).
When it matters: Helpful for estimating long-term electricity costs, particularly when running the unit continuously day and night.
Importance: HIGH
Alen 45i Pure Carbon has a higher power output than the average air purifier (50 W vs 37.5 W).50 W vs 37.5 W
Higher Manufacturer warranty
Alen 45i Pure Carbon offers higher Manufacturer warranty than the average air purifier (99 years vs $$$).
25 m² larger room area
Alen 45i Pure Carbon covers a larger room area than the average air purifier (74 m² vs 49 m²).
1 more fan speeds
Alen 45i Pure Carbon provides more fan speed settings than the average air purifier (4 vs 3).
4 dB lower maximum noise level
Alen 45i Pure Carbon runs quieter at maximum speed than the average air purifier (49 dB vs 53 dB).
12.5 W higher power
Alen 45i Pure Carbon has a higher power output than the average air purifier (50 W vs 37.5 W).
2.1% higher CADR
Alen 45i Pure Carbon provides a higher clean air delivery rate than the average air purifier (245 m³/h vs 240 m³/h).
Has a child lock
Alen 45i Pure Carbon has a child lock; the average air purifier does not.
Has an ionizer
Alen 45i Pure Carbon has an ionizer; the average air purifier does not.
0.5 m longer power cord
Alen 45i Pure Carbon features a longer power cord than the average air purifier (2.3 m vs 1.8 m).
Has a handle
Alen 45i Pure Carbon has a handle; the average air purifier does not.
0.5 cm shallower depth
Alen 45i Pure Carbon is shallower than the average air purifier (21.5 cm vs 22 cm).

Why is Alen 45i Pure Carbon worse than the average air purifier?

Show more

Hide

No washable prefilter
Alen 45i Pure Carbon does not have a washable prefilter; the average air purifier does.
No timer
Alen 45i Pure Carbon does not have a timer; the average air purifier does.
0.07 % percentage points lower bacteria elimination
Alen 45i Pure Carbon achieves lower certified bacteria elimination than the average air purifier (99.9% vs 99.97%).
10.8 cm wider width
Alen 45i Pure Carbon is wider than the average air purifier (38.1 cm vs 27.3 cm).
48.8% higher weight
Alen 45i Pure Carbon is heavier than the average air purifier (6.8 kg vs 4.57 kg).
13.5 cm taller height
Alen 45i Pure Carbon is taller than the average air purifier (63.5 cm vs 50 cm).
20759 cm³ larger external volume
Alen 45i Pure Carbon has a larger overall volume than the average air purifier (52016 cm³ vs 31257.025 cm³).
No washable prefilter
Alen 45i Pure Carbon does not have a washable prefilter; the average air purifier does.
What it is: A reusable outer mesh screen that traps hair, pet fur, and coarse dust, and can be rinsed clean under running water.
When it matters: Substantially extends the lifespan of expensive inner HEPA and carbon filters by stopping large debris from clogging them.
Importance: MEDIUM
Alen 45i Pure Carbon does not have a washable prefilter; the average air purifier does.
No timer
Alen 45i Pure Carbon does not have a timer; the average air purifier does.
What it is: A programmable shut-off countdown timer that turns off the air purifier automatically after a set number of hours.
When it matters: Convenient for running the unit for a specific duration before leaving home or going to bed without wasting electricity.
Importance: LOW
Alen 45i Pure Carbon does not have a timer; the average air purifier does.
0.07 % percentage points lower bacteria elimination
Alen 45i Pure Carbon achieves lower certified bacteria elimination than the average air purifier (99.9% vs 99.97%).
What it is: The certified laboratory efficiency percentage demonstrating the purifier's ability to eliminate airborne bacteria and microbes.
When it matters: Reassuring for hygiene-focused households, medical offices, or homes with infants where airborne pathogen reduction is a priority.
Importance: MEDIUM
Alen 45i Pure Carbon achieves lower certified bacteria elimination than the average air purifier (99.9% vs 99.97%).99.9 % vs 99.97 %
10.8 cm wider width
Alen 45i Pure Carbon is wider than the average air purifier (38.1 cm vs 27.3 cm).
What it is: The horizontal width across the front of the air purifier, measured in centimetres (cm).
When it matters: Essential for confirming the unit fits neatly between furniture, in tight corners, or on compact bedside tables.
Importance: LOW
Alen 45i Pure Carbon is wider than the average air purifier (38.1 cm vs 27.3 cm).38.1 cm vs 27.3 cm
48.8% higher weight
Alen 45i Pure Carbon is heavier than the average air purifier (6.8 kg vs 4.57 kg).
What it is: The total physical net weight of the air purifier without packaging, measured in kilograms (kg).
When it matters: Important if you frequently carry the purifier between rooms, to different floors, or place it on furniture.
Importance: MEDIUM
Alen 45i Pure Carbon is heavier than the average air purifier (6.8 kg vs 4.57 kg).6.8 kg vs 4.57 kg
13.5 cm taller height
Alen 45i Pure Carbon is taller than the average air purifier (63.5 cm vs 50 cm).
What it is: The vertical height of the air purifier unit, measured in centimetres (cm).
When it matters: Important for ensuring the unit fits underneath tables, under low window sills, or onto designated shelves.
Importance: LOW
Alen 45i Pure Carbon is taller than the average air purifier (63.5 cm vs 50 cm).63.5 cm vs 50 cm
2.71x more expensive
Alen 45i Pure Carbon is more expensive than the average air purifier (£380 vs £140).
Alen 45i Pure Carbon is more expensive than the average air purifier (£380 vs £140).£380 vs £140
20759 cm³ larger external volume
Alen 45i Pure Carbon has a larger overall volume than the average air purifier (52016 cm³ vs 31257.025 cm³).
What it is: This attribute shows the approximate external volume of the air purifier in cubic centimetres.
When it matters: It matters when comparing how much physical space different air purifiers occupy.
Importance: LOW
Alen 45i Pure Carbon has a larger overall volume than the average air purifier (52016 cm³ vs 31257.025 cm³).52016.025 cm³ vs 31257.025 cm³

Graphic comparison of Alen 45i Pure Carbon and other products in the Air Purifiers category

Attribute category

Attribute

No results found

Third-party reviews

United Kingdom

United States

(Reviews last updated: August 2026)

What customers like about Alen 45i Pure Carbon?

Noticeably improves indoor air quality by reducing dust, dander, and allergens
Effectively neutralizes cooking, pet, and smoke odors when utilizing the specialized carbon filters
Runs very quietly on lower fan speeds and generates a soothing pink noise profile
Features an accurate SmartSensor auto-mode that automatically adjusts fan speeds based on real-time air quality
Includes a lifetime warranty option conditional on maintaining an active OEM filter subscription
Modern design aesthetics with customizable panel colors to match home decor
User-friendly control interface that features adjustable display brightness and a color-coded air quality indicator wheel

What customers dislike about Alen 45i Pure Carbon?

High upfront purchase price compared to competing air purifiers with similar CADR metrics
Ongoing financial commitment due to expensive proprietary replacement filters required for the warranty
The standard entry-level 'Pure' filter option lacks activated carbon and is ineffective against household odors
Mobile app setup can occasionally be glitchy, providing limited functionality beyond standard panel controls
Unit is somewhat bulky and heavy, making it less portable despite having a integrated handle

Expert reviews

housefresh.com

17/12/2025

Summary of the review

Alen BreatheSmart 45i review - HouseFresh

The Alen BreatheSmart 45i is a premium air purifier designed for medium-sized rooms up to 301 square feet, offering high-performance H13 True HEPA filtration with a 208 CFM CADR. Key advantages include its exceptionally quiet operation, producing a soothing "pink noise" at lower speeds, alongside a highly accurate, responsive laser sensor for auto-mode, low energy consumption, and a, user-friendly interface. Conversely, the unit comes with a steep $419.00 price tag, offering lower value than the similar Alen Flex, and its,, lifetime warranty is tied to a, subscription, while its capacity is strictly limited to smaller spaces.

techradar.com

11/04/2024

Summary of the review

Alen BreatheSmart 45i air purifier review - TechRadar

The TechRadar review awards the Alen BreatheSmart 45i a 4.5/5-star rating, characterizing it as a fast, powerful, and user-friendly air purifier suited for medium-to-large spaces. Key advantages include an effective auto-mode with smart sensors, a convenient carrying handle, and an intuitive touch panel. However, notable drawbacks include a high purchase price, a bulky footprint, and limited odor-neutralizing capabilities with the stock filter, which requires an upgrade to remove smoke or odors.

Video reviews

Best alternatives

COWAY AIRMEGA 300S

Air Purifiers

Air Purifiers

Philips 2000i Series AC2889/10

Air Purifiers

Philips 2000 Series AC2887/10

Air Purifiers

Philips 3000i Series AC3033/10

Air Purifiers

Blueair Classic 480i

Air Purifiers

Philips 3000i Series AC3039/10

Air Purifiers

IQAir 250 0P 10 02

Air Purifiers

COWAY AIRMEGA 250S

Air Purifiers

Philips 2000i Series AC2729/10

Air Purifiers

Philips 5000i AC5659/10

Air Purifiers

Philips AMF870/15 Air Performer

Air Purifiers

Compare Alen 45i Pure Carbon with other products in the Air Purifiers category

Compare