Last updated: August 8, 2021

Our method

16Products analysed

55Hours spent

11Evaluated articles

75User reviews

Mould spores, fine dust as well as viruses and bacteria can seriously affect a person's quality of life. To counteract this, a so-called room air purifier could provide relief. This is because room air purifiers filter the polluted air and convert it into fresh air.

With our room air purifier test 2021 we want to help you find the best room air purifier for you. We have compared different air purifiers with different functions and listed the respective advantages and disadvantages. This should make your purchase decision as easy as possible.


  • Room air purifiers enable you to remove harmful substances such as viruses and bacteria as well as unpleasant odours from the air. This is achieved through specially installed filters and functions.
  • Especially useful for allergy sufferers, asthmatics and people with an immune deficiency, as pollen and mould spores can also be filtered.
  • Room air purifiers are available in all possible sizes and shapes. For large rooms, small rooms, for the classroom or for your own restaurant.

The Best Air Purifier: Our Picks

Room air purifiers: Purchase and evaluation criteria

In the following, we will show you which aspects you should look for when buying an air purifier. The criteria you can use to compare air purifiers with each other include:

In the following paragraphs, we will explain what is important in the individual criteria.

Size and weight

How big and how heavy should the optimal air purifier be? First of all, you need to know the size of the room in which the air is to be purified. As a rule, the larger and heavier the air purifier, the more machinery is installed in it, which leads to more power.

The wider the room, the larger and heavier the air purifier should be.

This means that in small, narrow rooms, a small room air purifier is sufficient to filter the air. In high, wide rooms, larger and heavier room air purifiers tend to be recommended.

The weight range of room air purifiers is usually between 1 and 15 kilograms. The recommended room size is 10 square metres for small room air purifiers and goes up to 120 square metres for large room air purifiers.

Degree of air purification

One of the most important criteria when buying a room air purifier is the degree of air purification. In order to know the degree of air purification of a room air purifier, the so-called CADR value is used.

The CADR value indicates the filter performance of room air purifiers.

It indicates how much room air is cleaned of three different types of particles of a certain size within one minute. The CADR value is used to compare the filter performance of room air cleaners.

The higher the CADR value, the better the filter performance of a room air purifier. The CADR values for room air purifiers range from 60 qbm/hour to 350 qbm/hour.


The filters of a room air purifier determine what and how well particles are removed from the air. That is why they are decisive for a good room air purifier.

  • HEPA filters: HEPA filters are filters that can filter more than 99.9 % of all particles from the air. They are integrated in almost all room air purifiers and work effectively against mould, bacteria and viruses. Class H13 or H14 filters are particularly suitable. The HEPA filter should ideally be replaced every six months.
  • Activated carbon filter: The activated carbon filter removes moisture from the air, which is particularly effective in eliminating odours. This can prevent unpleasant odours such as cigarette smoke. The activated carbon filter should also be replaced every six months.
  • Photocatalytic filter: The photocatalytic filter works in conjunction with UV light, which breaks down bacteria, viruses and toxic gases. The broken down bacteria and gases are collected in the filter. Consequently, the photocatalytic filter has its strengths in combating pollutants.
  • Ioniser: Although ionisers do not have a filter, they are able to bind pollutants and eliminate unpleasant odours. They generate negatively charged particles that bind the smallest particles in the room air. The bound particles are then filtered out with the help of a HEPA filter. However, when the ions are generated, ozone, a highly reactive gas, is formed as a by-product. If the concentration is too high, this ozone attacks the mucous membranes and causes headaches.
  • Ozone generator: In contrast to ionisers, ozone generators release ozone into the air as the main product and in larger quantities, which is why it can optimally eliminate very unpleasant odours. Due to the high concentration of ozone, rooms where air purification with an ozone generator is taking place should not be entered during this time. Afterwards, the room should be well ventilated to let the ozone escape.

HEPA and photocatalytic filters are the most reliable against viruses and bacteria.


A room air purifier often has additional functions for a maximum pleasant cleaning experience.

  1. Fan function: The fan function draws in the air contaminated with pollutants, which is then passed through the filter system of the air purifier. The strength can be set manually or, in the case of units with sensor-based control, automatically selected by the air purifier on the basis of the measured air quality.
  2. Timer function: The timer function determines the operation of the room air purifier at hourly intervals. After the pre-set time has elapsed, the unit switches off automatically.
  3. Air quality sensor: An air quality sensor measures the air quality in the room at regular intervals. The sensor automatically adjusts the fan and the air purification filter to the current level of air pollution.

Power consumption

The question of the power consumption of a room air purifier is important from the moment the room air purifier is put into operation. The higher the level at which the room air purifier runs, the greater the power consumption. The power consumption of a room air purifier starts at 20 watts and goes up to 70 watts.


The volume of a room air purifier also depends on the level set. The higher the level at which the air purifier runs, the louder the device. The volume of a room air purifier starts at 20 decibels and goes up to 70 decibels.

Room air purifiers: Frequently asked questions and answers

In the following, we would like to answer the most important questions about room air purifiers. We have selected the questions for you and will answer them shortly. After you have read through the guide, you will know all the essential background information about room air cleaners.

Who is a room air purifier suitable for?

In general, air purifiers are suitable for anyone who wants to breathe fresh air without pollutants. However, an air purifier is particularly useful for allergy sufferers, asthmatics and people in areas with a high level of fine dust pollution. This can significantly improve the quality of life of these population groups.


Especially in the catering industry, where many people are in close proximity to each other, room air cleaners could be helpful(Image source: Kelsey Chance/ unsplash)

In general, room air purifiers are recommended in all places where many people come together who could infect each other. Especially open-plan offices, classrooms as well as the catering industry could benefit from a room air purifier.

What types of air purifiers are there?

If you want to buy a room air purifier, there are several alternatives to choose from: We have compiled the most important advantages and disadvantages of all types below:

Type Advantages Disadvantages
HEPA filter Filters 99% of all particles in the air Must be replaced every 6 months
Activated carbon filter Binds and eliminates unpleasant odours Must be replaced every 6 months
Photocatalytic filter Removes viruses and bacteria most effectively Does not remove other particles effectively
Ioniser Binds pollutants and removes unpleasant odours Forms ozone as a by-product
Ozone generator Binds pollutants and removes unpleasant odours to a high degree Forms harmful ozone as a main product

The HEPA filter is a good all-rounder, which is installed in almost all room air purifiers, as it can filter even the smallest particles. The activated carbon filter, on the other hand, is only suitable for removing unpleasant odours. However, both filters should be replaced every six months. The photocatalytic filter has its strengths in combating viruses and bacteria.

However, it is less effective at removing other particles. The ioniser and the ozone generator bind pollutants and unpleasant odours. However, they both produce ozone, which can be harmful to health in high quantities.

How much does an air purifier cost?

The price of a room air purifier is mainly determined by how many square metres an air purifier can filter.

square metres price range
0-30 square metres 80-150 €
30-60 square metres 150-300 €
60-90 square metres 300-500 €
90-120 square metres 500-750 €

However, there are large fluctuations within the number of square metres, as the price is often increased by additional functions such as an app or certain sensors.

What alternatives are there to a room air purifier?

Alternatives to a room air purifier are the air washer and classic ventilation. We present both alternatives and show you the advantages and disadvantages.

Alternative Description Advantages Disadvantages
Air washer Air purification without filter, Leads to increased air humidity Binds larger particles,Pleasant in winter Does not bind smallest particles well,Unpleasant in summer
Airing Ventilating Free and easy Purifies the air less effectively

The air washer humidifies the air, thus increasing the humidity. This increased humidity is pleasant in winter, but can feel uncomfortable in summer. It also cleans the air less effectively than the room air purifier because it hardly filters small particles.

Unlike the room air purifier, an air washer does not have a filter to filter the smallest particles.


Ventilation allows pollutants in the air to escape. However, it is more ineffective than a room air purifier.(Image source:CHUTTERSNAP/ unsplash)

Traditional ventilation is simple and costs nothing, unlike the two devices. However, it is less effective in purifying the air as the air from inside is only exchanged with the air from outside. Both alternatives do not purify the air as effectively as a room air purifier, but they also have other strengths.


With the help of a room air purifier, you can filter all pollutants from the air in a room. In contrast to ventilation or air washers, the room air purifier fights the particles much more efficiently. When buying a room air purifier, it is important to consider which functions you prefer and how large the area to be cleaned is.

Especially for asthmatics and other risk groups, the purchase of a room air purifier goes hand in hand with an increase in quality of life. Once you have decided on your room air purifier, you only have to set the right level for your needs. Then you can take a deep breath without worrying about inhaling something toxic.

Picture source: Magraphics/