What is an air purifier and how to choose it

Depending on your objective, we recommend that your purifier be equipped with a specific type of technology.
An air purifier is a device that removes air pollutants such as toxic elements, smoke, suspended particles, allergens, mites etc. Its use is increasingly common for domestic use and may be beneficial for people with allergies, asthma, atopic dermatitis, chemical sensitivity and other diseases that may be affected by the presence of certain particles and that air purifiers can eliminate …

But beware, before buying an air purifier for therapeutic purposes it is important to verify that it has the endorsement of some medical society and invest a little time in comparing different models and brands.

What do you need? Do you need an air purifier to fight allergens, pollen, viruses, etc? Depending on your objective, we recommend that your purifier be equipped with a specific type of technology. Next we specify:

  • Plus oxygen filters: absorb odors and purify the air from the environment.
  • UV germicidal lamps and TiO2 catalyst filters decompose viruses, fungi and other allergens.
  • Oxidation by cold catalysis decomposes viruses, fungi and bacteria.
  • Negative ion generators help capture harmful particles.
  • Electrostatic precipitators capture pollutants and germs such as pollen, smoke, dust, pet hair or particles as small as 0.01 micron. In addition, it eliminates static electricity from the environment.

When choosing your air purifier it is important that you consider some factors. Below we suggest the key points when choosing which is best suited to your needs.

What factors should we consider when choosing an air purifier?


The power must be chosen according to the size of the room. A 30W air purifier will have the capacity to clean the air of a room of about 25-30 square meters, while a power 70W will be able to do it on a surface of 70-75 square meters.

Efficiency of filtering

Efficiency can be measured by the size of the captured particle. – 0.3 microns or smaller is an excellent size of the “catch” for any air purifier . Small particles of 0.3 to 5 microns include allergens such as bacteria or dust. So look for air filters or electronic air purifiers (ionizers) that can effectively trap large and small particles. Some air purifiers are equipped with an electrostatic precipitator that filters particles as small as 0.01 microns. The most recommended option is a purifier with a HEPA filter, which has the capacity to trap more than 99% of the particles in the air.

Power of the air flow: Refers to the number of cubic meters of air that the device is capable of filtering in one hour.

Energy consumption or Cost of the electricity bill

An “expensive” air purifier may end up being cheaper than a long-term economic unit. We have to take into account the cost of the utility bill, in addition to the cost of replacing the filters. It will always depend on the power of the machine, more power more consumption, although the most energy efficient appliances have automatic mode that help reduce the consumption of electricity. If they also have a timer, you can program the hours that are in operation. You will be able to adapt it to your needs and you will not have to be connected all day. It is one more element that will help you save.

Noise level or Sound level

Make it quiet, reduce the inconvenience during use. It is important to consider where you will be placed: in your bedroom, study, living room, … The acceptable level of noise in each of these rooms will vary. It is measured in decibels. It is essential to take into account if the purpose is to use it at night.

Replacement of filters

Many air purifiers come with a pre-filter. Its main function will be to remove the larger particles from the air to protect the more expensive filters. So many Brands incorporate permanent washable filters in their purifiers, without needing replacement. They are easy to remove and clean. It also reduces to 0 € the cost for the maintenance of the purifiers. Before buying the device check the frequency with which the filters must be changed (usually between 3 months and a year) and the price of them.

Area of ​​action

That is suitable for the surface of the room in which you use it. This is an important factor because the area of ​​action of an air purifier varies depending on the power of the model.


If you buy a cheap air purifier with a short warranty, you may find yourself replacing the unit earlier than desired. We believe that the brands that produce this type of technology must provide between 2 and 3 years of warranty. A safe air purifier should have no problem with the motor, fan, components and electrical controls. The rest of the air purifier consists of filters, which need periodic or replacement cleaning.

How do filters of air purifiers work?

The air purifiers work normally with a system of 4 stages, after which they can finish with more than 99% of the impurities of the air:

First filter: Catch solid particles (dust, hair …).
Second filter: It is activated carbon filter that eliminates smoke and odors.
Third filter: Eliminates allergens, mites and the finest dust.
Fourth filter: Eliminates the allergen formaldehyde. (The fourth filter is not available in all models, only in the highest range)

I hope this small guide to choosing a purifier has been useful for you.