How To Choose An Air Purifier?

How to choose an air purifier for your allergies?

According to Allergy UK, a whopping 44% of British adults now suffer from at least one allergy.

You may be allergic to indoor air pollutants such as tobacco smoke, dust particles, volatile organic compounds, pet dander or mould spores.  Maybe you are looking for an air purifier that can help reduce your symptoms by cleaning the air inside your house.

There are so many models on the market right now, at first it may seem quite overwhelming figuring out how to find the right air purifier for your needs.  Hopefully, after reading this short article, you will be well equipped with the knowledge to select the best air purifying solution for you.

So how do you know what air purifier to choose and what to consider when buying one?

Step 1.   Determine your main air quality concern

Well, first of all, think about why you need an air purifier in the first place.  What are you allergic to? Knowing the answer to this simple question will make selecting the right machine for you much more straightforward.

For instance, one unit may be great at removing pet dander and dust mites from a room, but not so good at removing bad smells and unwanted odours.  Most machines tend to fall into five common types depending on the technology used for combating indoor air pollution.  We are listing them below and if you want to learn more about each of the technology, go to the article "Do air purifiers work?" in which we dive deeper into each air purification technology commonly used in air purifiers.


  • HEPA-type, True-HEPA and activated carbon air filtration
  • Photocatalytic oxidation air sterilization (PCO)
  • UV-C air sterilisation
  • Ioniser air purification
  • Ozone generating air purification*


Best air purifiers use a combination of multiple types of air filtration technologies.  

* We strictly do not recommend investing in an air purifier that uses ozone generation for indoor air cleaning.  According to the California air resources board, these devices purposely emit large amounts of ozone that can pose a severe health risk to humans by harming the cells in the lungs and respiratory airways.

Step 2. Check and calculate your room size

A lot of people who invest in an air purifier end up choosing a machine that is too small for their living or working space.  You need to make sure that it is powerful enough to efficiently clean the air in the room and ultimately make a real difference in the quality of your life.

If you suffer from allergies to pollen, pet dander, dust mites or mould spores consider investing in an air purifier that can provide at least 4 complete air changes per hour (ACH).

If you suffer from asthma, consider investing in an air purifier that can provide at least 5 complete air changes per hour.

If cigarette smoke, household odours or volatile organic compounds are your main concerns consider going for an air purifier that can handle at least 8 air changes per hour.

If you are worried about the transmission of airborne infections, viruses and bacteria then choose an air purifier that can provide at least 6 air changes per hour (equivalent to the air circulation recommended for a private hospital bed).

And finally, for regular air cleaning choose an air purifier that can provide a minimum of 3 air changes per hour.

To begin, calculate the volume in which you are going to use the air purifier by multiplying the length, width and the height of your room.  

To find out how many air changes an air purifier will do in an hour simply find a clean air delivery rate (CADR) of the unit you are interested in, enter the dimensions of your room, and the handy calculator below will show you exactly how many air changes per hour you will have. CADR rating indicates how fast an air purifier can clean the air within a particular size room. It provides a way to compare air purifiers taking into account both airflow and a filter's efficiency.

 Step 3. Decide on the maintenance cost of an air purifier

Enjoying the pollutant-free air in your living or working space will involve individual costs, for example, the cost of electricity or replacement of filters or built-in modules such as UV-C and PCO units.

On average, HEPA filters need replacing every 12 months depending on the air purifier and the amount of particulate matter in the air.

Replacement carbon filters which capture odour molecules and chemical fumes in the air are not reusable and should be changed approximately every three months to a year.  

Pre-filters capture large particles such as pollen, pet hair and dander.  These filters can be vacuumed or washed with water.  

There are air purifiers that use ionisation air purification technology and don't require any filter replacement, for example - LightAir IonFlow air ionisers.

LightAir IonFlow Evolution Room Air Purifier - Aerify

When it comes to electricity costs, most modern air purifiers on the market put energy efficiency as one of their highest priorities since these machines are supposed to run for long periods.

CellFlow Mini 100 from LightAir, for example, is a very energy-efficient electrostatic air purifier that is suitable for small rooms up to 15 square meters.  It consumes only 1.6 – 3 watts of power, similar to an average smart speaker.

 LightAir CellFlow Mini Room Air Purifier - Aerify


Step 4. Decide on the features 

Once you get the hardest part out of the way, you may want to think about any additional features that you want your air purifier to have.  These can be air quality indicators in the form of an LED light that gives you real-time updates on the quality of the air inside your house.

Meaco Clean CA-HEPA 76x5 WiFi-enabled air purifier has a built-in particle sensor which analyses the air in the room and automatically varies the speed of a fan.  There is a colour change feature that works together with the sensor and the LED light.  The illumination either changes to red when the air is polluted or blue when the air is clean.  

Some other standard features that air purifiers may have are:

Night mode allows you to have a good night's sleep with an air purifier working quietly in the background.
Multiple fan speeds control airflow in the room.
Filter change reminders let you know precisely when a filter needs replacing.
Remote control allows you to operate an air purifier remotely.
Wi-Fi connectivity allows you to control an air purifier via an app on your phone or tablet.


We hope after reading this guide you have a better idea about how to choose an air purifier that addresses your needs.

Browse our product pages or view all our air purifiers in one place by clicking here

If you have any questions or concerns, contact us via live chat, email or phone, we will be happy to help.

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