Alen T100 HEPA Desktop Air Purifiers Review

Alen T100 HEPA Air Purifiers
Alen T100 HEPA Air Purifiers

The Alen T100 air purifier is good for someone who is looking for a small and compact air cleaner for their desktop that delivers acceptable levels of filtration at an appropriate price.

1. Airborne Particulate Filtration
2. Gas, Chemical & Odor Filtration
3. Room Coverage
4. Noise Rating
5. Filter Life & Replacement Costs
6. Ease of Operation & Filter Replacement
7. Quality of Construction: Air-tight design, no off-gassing
8. Electronic Filter Life Monitoring N/A
9. Manufacturer’s Credibility, Warranty & Return Policy
10. Quality of Filters
11. Value for Price


  • HEPA filter provides efficient removal of small irritating particles and allergens
  • Small and compact size fits nicely on a desk or bedside stand
  • It is extremely simple to operate and requires minimal maintenance
  • The filters are easy to access and replace
  • Lifetime Warranty as long as one replaces the filters every 6 months
  • Attractive design is not an eye sore to your desk or bedroom


  • The standard HEPA filter does not have enough carbon to sufficiently address gases and odors. For better gas and odor control we recommend the HEPA/Smoke/Odor MCP replacement filter.
  • Square foot coverage of this unit is small. It is best suited to clean the air in your personal area such as at your desk in the office, or in a small room under 125 sq. ft. (to achieve 6 air changes per hour, it will only clean 88 sq. ft.)
  • There are no indicators to tell you when the filters need to be changed


The Alen T100 is a nice looking little air purifier designed to clean the air in your personal space. It stands just under 15″ high and weights only 8 lbs making it convenient to use on a desktop or move from one room to the next. It uses a combination HEPA filter enhanced with a small amount of carbon and a washable foam pre-filter.

Its filtration performance is decent for a small air purifier. Our testing showed a 77% average reduction in particles on the first air pass. The T100 will do a good job reducing dust and helping to ease seasonal allergies, however it does not have the filtration performance necessary for those with severe allergies or asthma. The amount of carbon in the filter is minimal, so don’t expect it to tackle strong gas or chemical odors in the air. If you would like more sufficient gas and odor control you can replace the standard filter with the upgraded HEPA/Smoke/Odor MCP Filters which are $40 more. The washable pre-filter velcros to the front the HEPA to catch dust and pet hair that would otherwise clog the main filter. It is extremely easy to vacuum or wash requiring less than a minute of your time. In order to maintain Alen’s lifetime warranty, the filter must be changed every 6 months. Luckily, the T100 uses only 1 filter which is sold as a two pack, so for $49 you get a year’s worth of filtration and get to keep the lifetime warranty in effect. If you only run the air purifier for a few hours here and there, and do not care about the lifetime warranty, you will find the filter actually lasts much longer than 6 months. The filter is a breeze to change and will take less than 30 seconds of your time.

The T100’s square foot coverage is average for its size. The manufacturer states room coverage of 125 sq. ft. However, based on the fan’s delivered cfm, we found the room coverage to be only 88 sq. ft. with 6 air changes per hour. For allergy sufferers we always recommend 6 air changes per hour. Though the square foot coverage is small, it fits the purpose of this unit. The T100 is a small air purifier best suited for use in a small office, bedroom, or for providing clean air in your personal area.

We found this air purifier to be quiet on speed 1, which was not surprising considering its small size and the amount of air it moves. When you advance to speed 2 or 3 there is a significant increase in air flow, which directly affects the noise output. Although the fan noise is tolerable on the higher speeds, we did notice a whistling sound produced from the air being drawn through the inlet filter grill, which was an annoyance. The further away the unit is from you the less you will notice the whistling and the fan noise. We did discover that the whistling sound stopped if the filter grill cover was not securely attached – a fault in the design.

The control panel on the T100 is nicely designed and very user friendly. It offers 3 push buttons to control power, ionizer and fan speed. Each button is clearly labeled and the LCD panel shows if the ionizer is on and what speed the unit is on. The inclusion of some kind of electronic filter life indicator to tell when it is time to replace the filter would be a nice addition, as it is all too easy to forget how long a filter has been in use. As a helpful hint, we would suggest writing the date on the filter when you install it.
Overall, if you purchase this air purifier for the primary reason of effectively clean the air of allergens in a small room or personal work space, you should be more than satisfied. Based on our testing results and pros and cons of the T100, we give it a 3.5 star “good plus” rating.

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