Understanding air purifiers: How to use them most efficiently?

Article last updated September 9, 2026

Fresh indoor air to combat pollution has made air purifiers commonplace in many households. These devices work tirelessly to filter out contaminants and provide cleaner, healthier air. This article explores how air purifiers work and their benefits, and answers the most common questions along the way.

4 Types of Air Purifiers

From HEPA filters to activated carbon filters, each type of air purifier has its own specific advantages and limitations. By exploring different types of air purifiers, consumers can choose the best option to remove allergens, pollutants, and other contaminants from their living spaces .

1. Ultraviolet air purifiers

Ultraviolet air purifiers use UV-C light to kill bacteria, viruses, and other pathogens. Paired with a multi-stage filtration system, they capture particles while the UV-C light sterilizes the air and helps prevent mold growth. These air purifiers commonly use UV-C lamps for sterilization and mold prevention .

Ideal settings and specifications for UV air purifiers include multi-stage filtration systems to capture particles and impurities in the air, along with appropriate UV-C wattage to kill pathogens effectively.

2. HEPA air purifiers

HEPA (High Efficiency Particulate Air) air purifiers like the RENPHO Smart Air Purifier 089 are beneficial devices designed to improve indoor air quality by trapping small airborne particles such as pollen, dust, bacteria, and mold. These purifiers draw in air and pass it through a fine mesh filter that captures particles as small as 0.3 microns with 99.97% efficiency .

In addition to trapping particles, some HEPA air purifiers also include a gas filter for general gas and odor removal. This extra feature enhances the purifier's overall air-cleansing capabilities, making it a versatile choice for improving indoor air quality.

When considering a purchase, pay attention to MERV ratings, which measure how finely a filter captures particles, and the CADR numbers, which measure how much clean air the unit delivers per minute. Adding a gas filter also provides more comprehensive air purification .

3. Carbon filters

Volatile organic compounds (VOCs) emitted from various solids and liquids such as paints, cleaning supplies, and building materials can harm human health. Carbon filters remove these compounds through adsorption, attracting them to the carbon's porous surface and trapping them in the filter .

These filters differ from high-efficiency air filters because they remove gases and odors . In contrast, high-efficiency filters primarily remove particles such as dust, pollen, and mold spores.

4. Ionic air purifiers

Ionic air purifiers use electrostatic attraction to remove airborne particles. They charge airborne particles negatively, causing them to be attracted to a positively charged plate or filter within the purifier. This process effectively removes pollutants such as dust, pollen, and pet dander .

Some ionic air purifiers also produce ozone as a byproduct. Ozone is a molecule made up of three oxygen atoms. It can neutralize odors and kill bacteria and viruses. However, high levels of ozone can harm human health, so use caution when choosing an ionic air purifier that produces ozone .

In comparison, HEPA filter-based purifiers use physical filtration to capture particles in the air. These purifiers are highly effective at removing airborne pollutants. Still, they may not be as effective at neutralizing odors or killing bacteria and viruses.

How to maximize your air purifier efficiency?

As concerns about air quality and awareness of airborne allergens and contaminants grow, more people are turning to air purifiers to improve indoor air quality. To maximize air purifier use, some people leave these devices running continuously, day and night. But is doing that a good idea ? It depends on a few factors specific to your space.

Should you leave your air purifier on all the time?

Whether you should run an air purifier continuously depends on several factors, including your needs, the type of purifier you use, and your indoor environment. These five factors can help you make a decision :

1. Air quality concerns: If you live in a highly polluted area or have allergies or respiratory issues, running your air purifier constantly may help. Continuous operation ensures the air in your space is consistently filtered, reducing airborne particles that can trigger allergies or respiratory problems .

2. Noise levels: Some air purifiers can generate noise, especially at higher fan speeds. If noise is a concern, it may be preferable to run the device only when you're in the room or when the room is unoccupied .

3. Energy consumption: Running an air purifier continuously can consume a significant amount of energy, leading to higher electricity bills. If energy conservation is a priority, consider using the air purifier on a schedule or only when you are most likely to benefit from it .

4. Filter replacement and maintenance: Air purifiers typically have filters that require regular cleaning or replacement. Running the device constantly may require more frequent filter changes, which can increase cost and maintenance effort. Follow the manufacturer's guidelines for filter replacement and maintenance to ensure optimal performance .

5. Specific needs and concerns: Every individual's circumstances are unique. If you have specific health concerns, such as severe allergies or a compromised immune system, consult with a healthcare professional to determine the best air purifier usage strategy for your situation .

What are the potential drawbacks of using an air purifier all day?

Running an air purifier all day comes with a few trade-offs. Continuous use can increase energy costs, especially for models that use a lot of electricity. Ionic and ozone-generating purifiers carry their own risks — the ozone release can cause respiratory issues. Any purifier with a long runtime would also need more frequent filter checks; otherwise, it can leave room for bacterial growth in the filters if not properly maintained .

When should I turn my air purifier off?

There’s no strict rule for when to switch your air purifier off. In general, it’s optimal to keep it on whenever you are at home and want to maintain clean air quality. This is especially important if you have allergies, respiratory issues, or live in an area with high levels of air pollution. Running the air purifier consistently helps keep the air clean by removing particles and pollutants, giving you cleaner, healthier air to breathe. Ultimately, decide whether to turn off your air purifier based on your comfort and specific needs.

5 common reasons why your air purifier is not working properly

What happens when your air purifier doesn't seem to be working as effectively as it should? You may be experiencing issues for several reasons. From simple maintenance issues to more serious malfunctions, understanding the top reasons your air purifier isn't working can help you troubleshoot and resolve the problem quickly. That said, let's look at some of the most common reasons your air purifier may not be working properly and what you can do to fix it .

1. Air purifier is too small for the room

One of the most common reasons your air purifier is ineffective is its size relative to the room it's meant to clean. If it is undersized for the room, it may struggle to circulate and purify the air effectively, leaving you with subpar air quality. This can be problematic, especially if you have specific concerns like allergens, smoke, or volatile organic compounds (VOCs). To address this issue, consider upgrading to a larger model or adding additional units to cover the entire space. This will improve air purification and help you enjoy clean, fresh air throughout the room .

2. Air purifier is too close to a wall

When setting up your air purifier, make sure it is at least a couple of inches away from the wall. Placing it too close to the wall can restrict proper air circulation, reducing its effectiveness in purifying the indoor air. Additionally, avoid placing it in a corner, as this can also limit air circulation. Providing enough space for the air purifier to operate effectively is crucial in maintaining good indoor air quality .

3. Air purifier is on too low a setting

When the air purifier is set too low, it may not filter pollutants, allergens, and other airborne particles effectively, compromising air quality. To ensure proper air purification, adjust the air purifier to a higher setting .

Before making any adjustments, use an air quality meter to check the room's current air quality. This will help determine whether a lower setting is adequate or whether you need a higher setting for optimal air purification. After assessing the air quality, you can adjust the air purifier to a higher setting to ensure it effectively removes pollutants and maintains a clean, healthy indoor environment .

4. Air purifier needs to be cleaned

To maintain an air purifier properly, regularly clean and replace its components. Begin by vacuuming the pre-filter to remove any dust and larger particles. You can remove the fabric pre-filter and clean it in the washing machine, following the manufacturer's instructions. Clean the sensors as directed in the user manual to ensure they function properly .

When it's time to replace the main filter, follow the manufacturer's instructions carefully to remove and dispose of the old filter. Install the new filter according to the provided guidelines, and then reset the filter light indicator to ensure accurate monitoring of when the next replacement is needed .

5. Air purifier filter needs replacing

To replace the air purifier filter, start by consulting the manufacturer's instructions for your specific model. For optimal function and to maintain the warranty, use replacement parts from the original manufacturer. Using non-genuine parts may compromise the air purifier's effectiveness and lifespan. Following these steps and using genuine replacement parts will help the air purifier operate at its best and provide clean air for your space.

Takeaway

Ensuring clean, fresh indoor air is essential for maintaining a healthy environment. Air purifiers have become common household appliances to combat indoor air pollution. Assessing your circumstances and priorities can help you choose the best usage strategy. By making an informed decision, individuals can maximize the benefits of air purifiers and enjoy cleaner, healthier indoor air.