How To Choose An Air Purifier?

How do I choose an air purifier for my allergies?

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

You may have an allergy to indoor air pollutants such as tobacco smoke, dust particles, volatile organic compounds, pet dander or mould spores. Perhaps you are looking for an air purifier which can help reduce your symptoms by cleaning the air in your home.

There are so many models out there right now, at the beginning, it may seem quite overwhelming to understand how to find the right air purifier for your needs. Hopefully, after reading this brief article, you will be well equipped with the knowledge to select the best air purification solution for you.

So how do I know which air purifier to pick and what to consider when buying one?

Step 1.   Determine your primary air quality issue

Well, first off, think about why you need an air cleaner in the first place. What do you have an allergy to? Knowing the answer to this simple question will make the selection of the right machine for you far simpler.

For example, a unit may be excellent at removing pet dander and dust mites from a room, but not so good at removing bad smells and undesirable odours. Most machines tend to fall into five common types depending on the technology used for combating indoor air pollution.  We list them below and if you would like to find out more about each of the technologies, go to the article "Do air purifiers work?".


  • 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*


The best air purifiers use a mixture of several types of air filtration technologies. 

* We strongly recommend not investing in an air purifier that uses ozone production to clean indoor air.  According to the California Air Resources Board, they deliberately emit large quantities of ozone which may pose a serious risk to human health by damaging cells in the lungs and respiratory tract.

Step 2. Calculate the size of your room

Many people who invest in an air purifier end up choosing a machine that is too small for their environment. You need to ensure that it is powerful enough to effectively clean the air in the room so that it makes 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 have asthma, consider investing in an air purifier that can provide 5 or more complete air changes per hour.

If cigarette smoke, home smells or volatile organic compounds are your main concerns, consider going for an air cleaner 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).

Finally, for regular air cleansing, choose an air purifier that can provide at least 3 air changes per hour.

First, calculate the volume in which you will use the air purifier by multiplying the length, width and 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. Enter the size of your room, and the handy calculator below will show you exactly how many air changes per hour you will get. The CADR rating indicates how fast an air purifier can clean the air in a particular size room.  It provides a way to compare air purifiers taking into account both airflow and a filter's efficiency.

 Step 3. Determine the maintenance cost for an air cleaner

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 should be changed every 12 months based on the air purifier and the amount of particles in the air.

Replacement carbon filters that capture odour molecules and chemical vapours in the air are not reusable and should be replaced about every 3 months to one year. 

Pre-filters capture large particles like pollen, pet hair and dander. They can be vacuumed and washed in water.

There are air purifiers which use ionisation air purification technology and require no filter replacement, for example - LightAir IonFlow air ionisers.

LightAir IonFlow Evolution Room Air Purifier - Aerify

As for electricity costs, most modern air purifiers on the market place energy efficiency at the top of their priorities as these machines are supposed to be in operation for a long time.

For example, the LightAir CellFlow Mini 100 is a highly energy-efficient electrostatic air purifier suitable for small rooms up to 15 square metres.  It consumes only 1.6 to 3 watts of energy, as an average smart speaker.

 LightAir CellFlow Mini Room Air Purifier - Aerify


Step 4. Decide which features are of importance to you

Once you get the hardest part out of the way, you may want to think of all the extra features that you want your air purifier to have. These may be air quality indicators in the form of a LED light that gives you real-time updates on the air quality inside your home.

The Meaco Clean CA-HEPA 76x5 WiFi Air Purifier has a built-in particle sensor that analyzes the air in the room and automatically varies the speed of a fan. There is a color change function that works with both sensor and LED light.  It turns red when the air is polluted or blue when the air is clean. 

Other typical features of air purifiers include:

Night mode lets you have a good night's sleep with an air purifier working peacefully in the background.
Multiple fan speeds for controlling the airflow in the room.
Filter change reminders allow you to know exactly when a filter should be replaced.
Remote control allows you to operate an air purifier remotely.
Wi-Fi connectivity enables you to control an air purifier through an application on your phone or tablet.


We hope that after reading this guide you will have a better understanding of how to choose an air purifier that meets 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 through live chat, email or phone, we will be happy to assist you.

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