Last updated: August 6, 2021

Welcome to our big air purifier test 2021. Here we present all the air purifiers we have tested in detail. We have compiled detailed background information and added a summary of customer reviews on the web. We would like to make your purchase decision easier and help you find the best air purifier for you. You will also find answers to frequently asked questions in our guide. If available, we also offer interesting test videos. Furthermore, you will also find some important information on this page that you should definitely pay attention to if you want to buy an air purifier.




Summary

  • Air purifiers can provide a pleasant indoor climate. Basically, a distinction is made (roughly) between air purifiers with integrated filter systems, water-based air purifiers (air scrubbers), electrostatic air purifiers, thermal air purifiers and ionisers.
  • Various combinations or variations are also possible. Each of these types of air purifiers has its advantages and disadvantages; ultimately, it is a question of which one is right for you.
  • Health and hygiene aspects are particularly important to consider when it comes to indoor climate and air purification.

The best air purifier: Our Choices

Guide: Questions you should ask yourself before buying an air purifier

What are the advantages and disadvantages of an air purifier?

Air purifiers take harmful or dirty particles out of the air and clean them. These particles include bacteria, viruses, fungal spores, pollen, dust, volatile organic compounds (VOCs) and gases. But people with asthma or respiratory and mucous membrane complications can also benefit. In smokers' homes, unpleasant odours can also be neutralised and the air quality can be improved for the non-smokers in a household. Air purifiers thus fulfil a health function. Depending on the type and performance of the air purifier and the option mode set, more or fewer particles are filtered. The disadvantages are, on the one hand, not inconsiderable acquisition, operating (electricity, water) and replacement costs (filters, spare parts). In addition, as with any electrical device, a certain amount of cleaning is required from time to time. Furthermore, air purifiers can be more or less noisy, even if they usually have a night mode. The ozone mode helps against particularly strong odours, but it can also impair breathing and should therefore either be avoided or followed by ventilation. Overall, opinions are divided on the question of whether one should get an air purifier. Ultimately, it always depends on the specific individual case whether it makes sense to purchase an air purifier.

For whom is an air purifier suitable?

An air purifier is basically suitable for everyone. Clean air is pleasant for everyone, but especially people with special needs, such as allergy sufferers. However, in order for an air purifier to perform its function to the best of its ability, it must be thoroughly cleaned on a regular basis.

For which rooms is an air purifier suitable?

An air purifier is suitable for both large and smaller rooms. There are various models of air purifiers that are specially made for open-plan offices, for example. Therefore, it is especially important to find the right air purifier for the size of the room. For large rooms, it is advisable to choose a powerful air purifier that can easily run at a low power level. If, on the other hand, you choose an air purifier that is too weak or too small for a large living room, for example, it will hardly be able to keep the air clean to the desired degree even at the maximum power level.

What does an air purifier cost?

Inexpensive air purifiers are available for as little as a few euros. The more expensive versions, which offer considerable cleaning power, can cost several hundred up to 5,000 euros or more.

In a large price study, we examined a total of 195 products from the air purifier category to give you an overview. You can see the results here in our graph. Find out in our guide whether a product in the higher or lower price range is suitable for you.
(Source: Own representation)

For home use, however, the prices are usually up to several hundred euros.

What are the alternatives to an air purifier?

Indoor plants are sometimes cited as a natural alternative to air purifiers. Plants do indeed absorb particles and chemicals as well as carbon dioxide CO₂ and release oxygen into the air. However, their cleaning performance cannot be compared to that of an air purifier. For allergy sufferers, it is also important to remember that some plants do not even come into question - not so the air purifier. Another recommended alternative is to air the room several times a day. However, airing also has disadvantages: In summer, for example, the air inside the room heats up because warm air from outside enters the room. In winter, on the other hand, dry air gets outside and cools the inside temperature, which is why - as compensation - more heating power is required, which in turn drives up heating costs. For allergy sufferers, airing is hardly an effective alternative, especially in spring, as it allows more pollen to enter the room - which in turn can be filtered with an air purifier.

Decision: What types of air purifiers are there and which is the right one for you?

Depending on your needs, there are different types of air purifiers that can be roughly divided into the following categories:

  • Filter-based air purifier
  • Electrostatic air purifier
  • Air washer
  • Thermal air purifiers
  • Ionisers
  • Combination of the above categories and other variations

What distinguishes a filter-based air purifier and what are its advantages and disadvantages?

In an air purifier with an integrated filter system, the air is purified by various filters. The so-called pre-image (e.g. a grille) absorbs larger particles such as dust. It usually does not need to be replaced; however, it is recommended to clean it as soon as a certain amount of particles gets caught in it. According to the model, an activated carbon filter or HEPA filter ensures the removal of smaller particles. Activated carbon filters work like a sponge: chemical processes, which we will not go into here, ensure that smaller particles of pollution get stuck in the holes of the filter and are thus permanently removed from the indoor air. Activated carbon filters need to be replaced every few months HEPA filters, on the other hand, can be thought of as a thicket of filter material. Smaller particles stick to the filter fibres because they are driven there by the air flow of the filter. Larger particles stick to the filter fibre because of their size and inertia. Some air purifiers also have additional filters. The advantage of filter-based air purifiers is that they clean the air very quickly and effectively and are effective against even the smallest particles. The disadvantage of filter-based air purifiers is that the filters have to be replaced regularly. In addition, these air purifiers can be relatively loud, which is why they should not be placed in the bedroom. To give you a better idea of the volume, here is a video.

Advantages
  • Fast and effective
  • Smallest particles are filtered
Disadvantages
  • Filters must be replaced
  • Volume

What are the characteristics of an electrostatic air purifier and what are its advantages and disadvantages?

Electrostatic air cleaners suck in room air via a fan. The particles sucked in are positively charged in the process. Via so-called cut-offs, i.e. negatively charged particles, these dirt particles are bound and extracted from the room air. The advantage of electrostatic air cleaners is that no filters have to be replaced (as there are none) and no water has to be refilled. Of course, the cut-offs must be cleaned at regular intervals. Particularly small particles may not be sucked in. Volatile organic compounds are also not neutralised.

Advantages

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Disadvantages
  • Cleaning effort
  • Not suitable for very small particles and VOCs

What are the characteristics of an air washer and what are its advantages and disadvantages?

The air scrubber sucks particles out of the air and binds them to water particles with the help of high-speed rotating wet plates. As these plates rotate on the water, they are rinsed out at the same time.

The air washer offers the advantage that it both cleans and humidifies the air, which helps to combat the health disadvantages of excessively dry air (dryness of the mucous membranes, coughing, tiredness, etc.), especially in winter. A disadvantage of the air washer is that water has to be refilled and the filter has to be cleaned thoroughly every few months, otherwise mould and bacteria can settle in it.

Advantages
  • Simultaneous cleaning and humidification
Disadvantages
  • Water consumption
  • Extensive cleaning

What are the characteristics of a thermal air purifier and what are its advantages and disadvantages?

A thermal air purifier cleans the air, as its name suggests, by absorbing particles and heating them to 200° on a ceramic core inside the purifier.

In this way, even the smallest particles are rendered harmless - most germs already die at around 60° to 100°.

Thermal air cleaners offer many advantages. For one thing, there is no need to replace filters, refill water and the like. Secondly, they are practically noiseless and consume little electricity. A major disadvantage might be the relatively slow speed of cleaning. In addition, they are not effective against VOCs.

Advantages
  • No filter or water costs
  • Practically noiseless
  • Low power consumption
Disadvantages
  • Relatively slow
  • Does not work against VOCs

What are the characteristics of an ioniser and what are its advantages and disadvantages?

Ionisers clean the air by - the name suggests - ionisation. In short, particles from the air are bound by means of negatively charged electrons, whereby they become inert and "fall" to the ground. This means that in normal cases (i.e. unless you are lying on the floor) they are not directly inhaled. Ionisers offer the advantage that they are silent and there are no filter or water costs. However, the "filtered" particles remain in the room and can at best be stirred up. In addition, ionisers can generate ozone, which is why their effect as air purifiers is controversial. Ultimately, ionisers do not remove the particles, but prevent them from being directly inhaled through the air.

Advantages
  • No filter or water costs
  • Virtually silent
Disadvantages
  • Particles remain on the floor of the room
  • Generation of ozone

Buying criteria: These are the factors you can use to compare and evaluate air purifiers

In the following, we will show you which features you can use to decide between the many possible air purifiers. These are namely:

  • Recommended room size
  • Volume
  • Cleaned Air Delivery Rate (CADR)
  • Design
  • Other criteria as required

In the following paragraphs we will explain to you what exactly is important in the individual criteria.

Recommended room size

By room size we mean not only the area (length x width), but also the volume (length x width x height) of the room.

Smaller air purifiers are only suitable for smaller rooms because of their lower cleaning performance. (Picture source: 123rf.com / 62980621)

Even when set to the maximum level, the performance of small devices - despite relatively high noise levels and high consumption (!) - is often not sufficient. If you want to ensure that the air in larger rooms is also cleaned effectively, you should choose a powerful air purifier that can also be operated on a low setting if necessary without the cleaning performance suffering.

Volume

Air purifiers can produce more or less noise, depending on the type (see above). Generally, values between 40 and 60 dB are given for the "noisy" variants. For room noise (normal conversation between people), a value of 60 dB is generally given. Air cleaners are therefore not particularly loud compared to a busy room in which several people are talking. Nevertheless, if you have sensitive ears or suffer from sleep disorders, you should not necessarily place your air purifier (except for ionisers and thermal air purifiers) on your bedroom dresser.

Remember: 10 dB more means a perceived doubling of the volume, 10 dB less means a halving.

Cleaned Air Delivery Rate (CADR)

The CADR is expressed in cubic feet per minute (CFM) and tells you how much air per minute is cleaned of particles of certain sizes (specifically: X) for a standardised room size of 28.5 m³. The CADR should never be used as the sole criterion for a purchase decision, especially when it comes to filtering VOCs.

Design

Finally, the design is a criterion that should not be neglected, unless the air purifier of your choice is to be placed in your craft room. Ideally, air purifiers not only provide a pleasant indoor climate through their cleaning performance, but also thanks to their design. An example of this is air purifiers made of Swiss stone pine, which convey a very appealing, rustic image.

Since this is a qualitative criterion that cannot be measured but depends on taste, the question of which air purifier suits you and your rooms cannot be answered conclusively.

Other criteria

Depending on the type and needs of the user, other criteria are decisive, such as the cost of replacement filters, water consumption for air washers, suitability for pollen filtration for allergy sufferers etc.

Interesting facts about air purifiers

Where is the best place to install an air purifier?

Depending on the type and volume of the air purifier, you should not necessarily place it on your dresser a few centimetres from your pillow. In the case of air washers, there are a few special features to consider because of the additional humidification of the air. Firstly, you should place the air washer at some distance from electrical appliances (TV, radio, modem). Finally, the air washer should not be placed near the window, as otherwise the pane will mist up - especially at low temperatures - and the water vapour will drip down the pane rather than being distributed in the air.

To prevent the window from looking like this, an air washer should be placed at a distance. (Image source: pixabay.com / Pexels)

Secondly, the floor is not a recommended location. Especially with materials like wood, which reacts sensitively to too much moisture, you should ensure a certain distance. Damp tiles are slippery. A cable can easily be overlooked, and stumbling over a full water tank is not exactly pleasant, as you should be aware. Otherwise, it is basically up to you where you want to place your air purifier. Again, "it depends"

How do I care for and clean an air purifier?

Since it is an electrical appliance: Switch off and unplug the air purifier before cleaning. Filters must be replaced at regular intervals. The best way to remove limescale that forms when the air purifier is used for a long time is to use disinfectants or vinegar. Alternatively, you can use citric acid or commercially available descaling agents. Pour the descaling agent into a little water, let it stand for about 30 minutes and rinse thoroughly. Electrostatic and thermal air cleaners as well as ionisers, on the other hand, do not pose any problems in terms of replacement or limescale, as they have neither a filter system nor a water tank. With electrostatic air cleaners, however, the separators should be thoroughly rinsed out with water. The cleaning of any air purifier should be done gently, as with all household appliances. You can easily use household wipes to remove stains. Always make sure that no scratches form and clean and disinfect your air purifier at regular intervals (the more intensive the use, the more often it needs to be cleaned).

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