The differences between an air purifier and a humidifier

With a goal of achieving a healthier indoor environment, many people turn to appliances such as air purifiers and humidifiers. Indeed, both appliances aim to improve air quality, but they serve very distinct purposes. Understanding the differences between these two devices is crucial in selecting the ideal solution for your specific air quality needs. Read on to learn more about the differences between air purifiers and humidifiers.

A woman sitting next to an air purifier (left) and a humidifier (right)

Differences between air purifiers and humidifiers

Purpose and function

Air purifiers and humidifiers cater to different aspects of air quality in the home and other indoor spaces. The primary objective of air purifiers is to cleanse the air of pollutants and allergens like dust, pollen, smoke, and mould spores. This enhances indoor air quality and promotes improved respiratory health, especially for those who are triggered by airborne pollutants (especially individuals with allergies, respiratory issues, and/or living in areas with high levels of air pollution).

Humidifiers, on the other hand, are designed to increase the moisture content in the air, thereby raising indoor humidity levels. Humidifiers emit water vapour (moisture) into the indoor air and aim to counteract dry air conditions counteracting dry air conditions. A humidifier may help alleviate symptoms of dry skin, sinus congestion, and other discomforts caused by dry air.

How they work

Air purifiers typically use one or more filters to trap air pollution particles like allergens and fine particles. This is done by using a powerful fan to pull in polluted air in the home, treating that air within the device, then using its powerful fan once more to recirculate purified air back into your space. Filter types vary from model to model (read more in the ‘Device types’ section below).

Humidifiers add moisture to the air by using a fan to circulate evaporated water. This may be done either by emitting cool/room temperature water vapour or heating water in the device and releasing steam.

Key benefits

One of the main benefits of investing in an air purifier is improved respiratory health. If your primary concern is to alleviate respiratory symptoms from allergies, asthma, and/or COPD by removing airborne pollutants and allergens (such as dust, pollen, or pet dander), an air purifier makes a great choice. They are also beneficial in protecting you from fine particle pollution emitted by traffic, industrial emissions, cigarette and/or cannabis smoke, candle and/or incense burning, and cooking and/or heating with natural gas or wood. Air purifiers equipped with the proper technologies, like activated carbon filters, also help protect you from chemical pollution released by cleaning products, DIY products (paint, sealants, glues, adhesives, etc.), and pesticides, to name a few.  Activated carbon filters also help with the elimination of odours.

Humidifiers are effective in preventing symptoms related to dryness like dry skin and respiratory discomfort. Humidifying the air in your home may also help protect wooden furniture and musical instruments from damage. Furthermore, a humidifier may help lower heating and electricity bills by making cool air feel warmer.

Device types

Types of air purifiers

As mentioned above, air purifier models vary extensively. One of the main featured filtration technologies includes HEPA (High Efficiency Particulate Air) filtration. HEPA filters are considered to be the gold standard of air filtration in air purifiers as they guarantee the removal of 99.97% of particles down to a size of 0.3 microns in diameter (Eoleaf’s HEPA filters remove particles down to a size of 0.01 microns!) in a single pass (including PM10, PM2.5, and PM0.1). More modern devices, like those on offer at Eoleaf, contain those technologies and more, including:

Eoleaf's AEROPRO 100 air purifier

Types of humidifiers

Humidifiers also vary regarding the technologies they use, but their goal remains the same: to reintroduce humidity into your indoor air. There are typically three types of humidifiers:

  • Evaporative humidifier – also known as a cool mist humidifier, these devices blow cool or room temperature air through a wet filter (also called a wet wick) causing water to evaporate water vapour; they require regular filter changes
  • Ultrasonic humidifier – another type of cool mist humidifier, these use ultrasonic, high-frequency sound vibrations to break water into droplets, (creating a fine mist of water) and then use a fan to propel them into the air in an indoor area; they do not require filters
  • Warm mist (or steam) humidifiers (also known as steam vaporisers) – these devices are different from the two other categories because they boil water inside the device, causing it to convert from a liquid to a gas (creating steam), which permeates and adds moisture to the air; these can also warm up your room2
A woman in her home next to a small humidifier

Choosing the right device for your needs

Assess your environment

When deciding between an air purifier and a humidifier, consider your primary concerns and assess the specific needs of your indoor environment. If you suffer from allergies and/or live in an area that experiences high levels of outdoor pollution, an air purifier is the recommended device. Air purifiers are also recommended for those that live with smokers, pets, and/or those who use polluting products indoors like cleaning agents, pesticides, candles and/or incense, or natural gas or wood for heating or cooking.

If your main concern is to combat discomfort due to dry air, such as dry skin, nasal congestion, or static electricity buildup, a humidifier would be the right choice. Humidifiers are ideal for those living in a particularly dry climate.

In some cases, a combination of both devices may be necessary in order to achieve optimal indoor air quality. For example, during the winter months when heating systems are in use, indoor air tends to become dry, leading to respiratory discomfort. In such situations, using a humidifier to increase humidity levels and an air purifier to remove airborne pollutants may provide comprehensive air quality improvement.

Health considerations

People with respiratory conditions and symptoms caused by allergies, asthma, COPD, pulmonary embolism, lung cancer, and more, an air purifier is very beneficial in helping to alleviate those symptoms.

If you are prone to dry skin, a humidifier device would be more beneficial. 

If you are experiencing severe symptoms causing you significant discomfort, it is always recommended to seek guidance from your healthcare provider.

Maintenance and care

Devices of all types require maintenance and care. Air purifiers, regardless of the model, require filter changes at regular intervals. This is essential in ensuring that your device continues to provide the same level of air filtration. Filters in an air purifier become saturated with the pollutants it has captured over time, and if a device with a saturated filter continues to be used, those pollutants may actually be re-released into your space. Lower-quality filters require changing multiple times per year, whereas high-quality filters, like those in Eoleaf products, only require changing once per year.

Maintenance required for humidifiers depends upon the humidifier type. As previously mentioned, evaporative humidifiers have wet filters (wicks) that must be replaced periodically. Ultrasonic humidifiers do not require filter changes. All humidifiers require regular cleaning and upkeep, however, to prevent the buildup of mould, mildew, and bacteria and for the devices to operate effectively.

For both air purifiers and humidifiers, be sure to follow the manufacturer’s instructions for cleaning and replacing filters and parts. 

In summary

Air purifiers and humidifiers serve distinct yet complementary purposes in enhancing indoor air quality. Air purifiers focus on removing airborne contaminants like allergens, and humidifiers work to increase moisture levels in the air. Understanding the differences and respective benefits of these devices allows individuals to make informed decisions to create healthier and more comfortable indoor environments. Whether tackling allergies, respiratory issues, or dry air discomfort, selecting the right solution significantly improves overall well-being and quality of life.

A woman in her home looking out the window

Frequently asked questions

What is the primary function of an air purifier compared to a humidifier?

The main purpose of an air purifier is to remove airborne contaminants and pollutants like allergens (pollen, pet hair and dander, dust and dust mites, mould and spores), VOCs, and fine particle pollution (particulate matter). Humidifiers aim to increase the level of humidity in your indoor space by emitting water vapour into the air.

Can air purifiers remove moisture from the air like dehumidifiers do?

No. Air purifiers are designed to remove pollutants from the air, not to add moisture. Filters in air purifiers may be damaged by excess humidity and/or drastic temperature changes which is why the two functionalities are rarely offered in the same device.

Do humidifiers help clean the air of pollutants?

No. Humidifiers do not come equipped with any pollutant or allergen-removing technologies. Additionally, extra care must be taken to ensure that only clean water is used in a humidifier. Dispersing contaminated water vapour into the air may create further indoor air quality and health issues.

How do air purifiers and humidifiers affect people with allergies or asthma?

Both devices may be beneficial for people with allergies and/or asthma. Air purifiers remove airborne contaminants that trigger allergies (allergens) and asthma, significantly relieving symptoms of both conditions. Humidifiers may help reduce inflammation that causes nasal congestion and irritation of the nasal mucosa. However, humidity levels must be monitored with caution. Humidity levels that are too low may cause respiratory discomfort and dry skin, but humidity levels that are too high may encourage the proliferation of mould and dust mites2

Are there any health risks associated with using either air purifiers or humidifiers?

Health risks associated with air purifiers are caused by improper maintenance. If filters are not changed at regular intervals, pollutants may be released back into your indoor environment. Humidifiers, on the other hand, may create environments that are overly humid, potentially leading to proliferation of mould and dust mites, exposure to which may cause further health issues.

Can I use an air purifier and a humidifier in the same room effectively?

This is not recommended. Filters in air purifiers may become damaged in humid environments. Humidity causes filters to become saturated with water droplets, making it impossible for them to filter the air effectively. This is why we also never recommend installing an air purifier in a bathroom or laundry room.

What maintenance is required for air purifiers versus humidifiers?

Air purifiers all require regular filter changes. The interval at which filters must be changed depends upon the manufacturer (Eoleaf’s devices only require filter changes once per month). Evaporative humidifiers require periodic changes of their wet filters (or wicks), whereas other types of humidifiers do not need filter changes. All humidifiers require regular cleaning to ensure that bacteria, mould, and/or mildew do not build up.


1 How does a humidifier work? All your questions answered. Sleepopolis. (2023, June 13). 

2 Kiefer, D. (2018, August 20). How humidifiers can help allergies. Healthline. 

Eoleaf's range of air purifiers

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