Filtrete Ultra Clean Room Air Purifier Review

Filtrete Ultra Clean Room Air Purifier Review

In this Filtrete Ultra Clean Large Room Air Purifier review, we look at the largest air purifiers of the Filtrete range of air cleaners. It retails between £170 and £199. Filtrete Ultra Clean Air Purifier uses an electrostatic polyester filter, which costs £19.99 and is recommended by the manufacturer to be replaced every 3 months. The Filtrete Ultra Clean offers three-speed settings, comes with a filter life indicator, weighs 10 kg (22lbs) and is manufactured in China.


  • Contemporary design
  • Low price point


  • X High level of maintenance
  • X No pre-filter
  • X Not leakage-free
  • X No gas, chemical & odour filtration

Marketed as:

Filtrete is owned by 3M, a large consumer goods company based in the USA. Filtrete specializes in air and water filtration and offers an air purifier range comprising of three different size air purifiers.

The Filtrete Ultra Clean air cleaner is advertised as featuring “state of the art filtration technology”[1] and “the perfect balance of low noise, high clean air delivery rate and value for money”[2]. The unit is recommended as being suitable for rooms up to 34m2 (365ft2) and is said to offer a "99.9% filtration rate of large particles". The manufacturer also says that the Filtrete Ultra Clean air cleaner has a “28% higher airflow than a HEPA purifier”[3] and that the air cleaner is “99.9% effective at removing particles from the air which passes through the purifier”[4].

The Filtrete Ultra Clean is clearly marketed towards people with general allergies and breathing difficulties[5]. Filtrete, nor any of its retailers, however, give any concrete details about the actual filtration efficiency of the air purifier as a whole, its filter or of its airflow.


When we opened the Filtrete Ultra Clean air purifier we were pleasantly surprised by the low key but modern design of the unit. The size of the unit does not make it too overbearing on space and will ‘fit in’ with most modern offices or homes.

The marketing material on the box is relatively gimmick-free and does not make obvious exaggerations in terms of what is realistic to expect from an air purifier in this price range. However, on the Filtrete website, the air purifier is advertised as being “99.9% effective at removing particles from the air which passes through the purifier”[6]. On another page on their site, Filtrete says that the unit “captures 99.9% of particles from air passing through the filter”[7]. It is important here to point out that there is a large difference between these two quotes. A unit’s ‘whole system filtration efficiency’ is not the same as a units ‘theoretical’ filter medium filtration efficiency. Filtrete makes it sound as if the Ultra Clean Large Room Air Purifier has a whole system efficiency of 99.9%.


Now the obvious question is: 99.9% of what? Sticks and stones? Normally we would assume that the percentage relates to particulate pollution at 0.3 microns (which would be the industry standard). But that is not the case here as Filtrete states that 99.9% only relates to ‘large particles’, without explaining how they define ‘large particles’.

It is a bit curious that Filtrete is not giving a more precise filtration efficiency. It is, after all, the fine and ultra-fine particulates that people care most about, as they are the most harmful to your health and the most difficult to filter out of the air. An air purifier with a low filtration efficiency for fine and ultra-fine pollution will be of little use for most people with mild to severe allergies and would certainly only provide a very limited to no protection from common contamination such as traffic pollution.


The type of filter used in the Filtrete Ultra Clean  Air Purifier is an electrostatic polyester mesh filter. The filter will have a small static charge when it is new (that’s why it is wrapped in plastic and should be used as soon as it has been unpacked) that helps to collect and retain pollution. This kind of filtration is, however, not great in achieving a) a consistent filtration efficiency, b) an especially high filtration efficiency over a given period of time, and c) a long filter life.

The Filtrete Ultra Clean does not have a pre-filter of any sort and as a result, larger particulates clog up the electrostatic filter more quickly – resulting in a relatively short filter life of only 3 months.

The Filtrete Ultra Clean also does not have any gas or chemical filtration. This means it will have little or no effect on common airborne gasses, chemicals, and odours such as VOCs, traffic fumes, cigarette smoke or pet dander. This is a drawback and makes the unit unsuitable for people who suffer with rhinitis, asthma or Multiple Chemical Sensitivity.

Airflow & Filtration Efficiency:

The Filtrete Ultra Clean is marketed as being designed for room sizes up to 34m2 (365ft2). The manufacturer and its retailers, however, do not list the actual airflow of the air purifier anywhere. Instead, Filtrete only lists the Clean Air Delivery Rate (CADR) of the unit. There are several reasons why we do not like to use CADR ratings. One is that CADR testing is not especially objective (as it is the association of manufacturers that does the testing). Furthermore, the test is flawed as it only tests units for 120 seconds and does not take gas and chemical contamination into account (to find out more about CADR visit our CADR blog post).

So it is disappointing that there is no information on the actual airflow and filtration efficiency of the Filtrete Ultra Clean air cleaner. We contacted Filtrete and also a couple of its retailers but did not receive any adequate responses. This made us a bit sceptical of the units actual performance, as it seems odd for a manufacturer not to release the two most important performance indicators of air purifier and only – misleadingly so - say that it has a "99.9% filtration rate for large particles".

In the USA, Filtrete offers a similar electrostatic polyester mesh filter with five different filtration efficiencies. These filters range between a MERV (Minimum Efficiency Reporting Value) 8 and 15. The highest MERV rated filter (and most expensive one) that Filtrete offers are the Elite 2200 which has a filtration efficiency at 0.3 microns of 95%. But again, as it is an electrostatic filter, the question is how the filtration efficiency will change over time.

It is obvious that the Filtrete Ultra Clean air purifier is not designed to be leakage free. This means that unfiltered polluted air can bypass the filter and be released back into the room. As the Filtrete Ultra Clean’s electrostatic filter becomes more loaded, more and more pollution escapes past the filter. This obviously hampers the air purifier’s efficiency to properly clean the air.

The Filtrete Ultra Clean air cleaner comes with what is advertised as a “filter life indicator” (See Image 1). This indicator is more of a day countdown timer. It counts down 90 days before reminding the owner to replace the filter. It takes no account of the number of hours used or speeds setting the unit is running on, and as a result is of little use. You might as well set an alarm on your mobile phone or computer to remind you to replace the filter.

There is also somewhat of a design fault with the Filtrete Ultra Clean Air Purifier in so far that the unit has an open, uncovered top (where the clean air comes out). This open surface is prone to collect dust when the unit is switched off (See Image 6). This is inconvenient, as it is difficult/impossible to simply clean the inside of the Filtrete Ultra Clean and if the air purifier is switched on again, the collected dust is blown back into the room. Thus, we would recommend to cover this part of the unit when the air purifier is in storage or not used.


The Filtrete Ultra Clean Large Room Air Purifier is a good but also very basic air purifier. It is not suited for serious air pollution concerns or people suffering with asthma, MCS or other severe allergies.

The filter will have to be changed often, and the filtration efficiency can significantly change the longer the filters have been used.  The lack of activated carbon means that the Filtrete Ultra Clean is not able to deal with odours, VOCs and other harmful gasses such as traffic fumes.

The air purifier is not leakage free, which is excusable for an air cleaner in this price range (and if you are not dealing with a serious contamination issue or severe allergies and asthma). However, what is not excusable is that the manufacturer is overly secretive about the air purifier’s actual performance in terms of filtration efficiency and airflow - to the point that we feel the information Filtrete is providing is misleading.  If you buy an air purifier you need to know the units actual filtration efficiency and airflow, and it is the manufacturer's and the retailers' responsibility to provide this information to you.


  Price:   £170.00 - £199.00 (inc. VAT)
  Weight:   10kgs (22.4 lbs)
  Size:   70.5 x 50.8 x 23.6cm (Inches: 27.5 x 20 x 9.3)
  Filter type(s):   Electrostatic filter
  Frequency of filter change:   3-6 months
  Cost of filter:   £19.99 (inc. VAT)
  Theoretical filtration efficiency (according to manufacturer):   Not given
  Actual filtration efficiency:   Not given
  Air flow on highest speed setting:   Not given
  Adequate room size (according to manufacturer):   up to 34m2 (365ft2)
  Country of manufacture:   China
  Power consumption:   176.8 W
  Warranty:   2 years

Customer Reviews:

[1 - 4]  portal/3M/en_GB/EU-Filtrete/Home/2/Products/  UltraCleanLarge/

[5]   p-697-filtrete-ultra-clean-room-air-purifier-large-   fap03.aspx

[6]   portal/3M/en_GB/EU-Filtrete/   Home/2/Products/

[7]   portal/3M/en_GB/EU-Filtrete/Home/2/Products/  UltraCleanLarge/



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