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HVAC Air Purifier – What Is It For? How It Works? Common Problems?

If you live in a city or suburban area, you’re probably concerned about the air pollution levels around you. Unfortunately, the air inside your home or office could be more polluted than you think. Thankfully, HVAC (Heating, ventilation, and air conditioning) air purifiers do an excellent job of purifying the air, but how do they work?

An HVAC air purifier is part of an HVAC system and removes airborne contaminants. It has a fan and filters that capture pollutants, and pushes clean, filtered air back into the room. Some common problems with the HVAC air purifier system are reduced airflow and high energy costs.

In this article, I’ll discuss what an HVAC purifier is, how it works, and what the best air purifier is. I’ll also provide some of the drawbacks of using them. Let’s get started! 

What Is an HVAC Air Purifier?

An HVAC air purifier functions as an air filter, and is an additional air filtration system on your HVAC unit. It can remove pollen, dust, smoke, and other airborne particles from the air, making it healthier to breathe.

HVAC air purifiers are an excellent addition to your HVAC system, and are more effective at purifying the air than conventional paper filters.

How an HVAC Air Purifier Works?

An HVAC air purifier removes contaminants from the air, and pulls the air in from the living space. The air then travels through a filter via the following process: 

  1. The air purifier has fans that pull the room’s air into the unit.
  2. The travels air through filters.
  3. The filters trap contaminants such as allergens, dust, pollen, and particulate matter.
  4. The system circulates the clean air back into the room.

HVAC air purifiers come in many different sizes and styles. However, their air cleaning mechanisms aren’t uniform, so you can choose one that fits your needs.

Types of HVAC Air Purifiers 

Below, I’ll take an in-depth look at the various HVAC air purifiers available: 

HEPA Filters

HEPA (High-Efficiency Particulate Air) filters are incredibly popular and for good reason. They do an excellent job of purifying the air, and can remove up to 99% of airborne pollutants. The filters are one of the most common HVAC air purifying systems.

HEPA purifiers use heavy-duty filters for maximum performance. This effectively cleans particles that measure more than 0.3 microns in size. Their multi-layered netting has various-sized gaps to capture variously sized particles. 

Here are a few examples:

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  • The filter traps large particles via impaction. Impaction involves tiny air particles crashing into the fiber. These particles are too large to pass through the filter’s fibers.
  • The filter also captures medium-sized particles through interception. This happens when the fiber traps the dirt on impact.
  • For ultra-small particles, the HEPA filter captures them through diffusion. When the dirt moves around the filter, it sticks to the fiber.

Read: How Can I Test The Air Quality Myself?

Electrostatic Filters

These HVAC air purifiers contain electrostatic fields. The electrostatic fields trap microscopic particles from indoor air, and they can even capture viruses and small particles as small as 0.1 microns.

Electrostatic air filters use static electricity to clean air. They generate an electrostatic charge when air flows through a series of static-prone fibers, and the static electricity captures the tiny particles and keeps them in the filter. 

Ionizing Air Filters

This is how the ionizing air filter works:

  1. The air purifier produces negatively charged ions.
  2. The ions attract and trap positively charged indoor air particles and create groups of tiny particles that stick together.
  3. The particles eventually become too heavy to remain in the air.
  4. The HVAC filtration unit captures these particles and removes them from the air.

Read: How Is Indoor Air Quality Measured?

Ultraviolet Filters

Ultraviolet filters use short-wave light to eliminate viruses and bacteria from the air. The UV lamps disinfect indoor air with germicidal radiation when the air passes through your HVAC system.

Ultraviolet filters are an ideal solution to eliminate contaminated air from your indoor spaces. They trap microorganisms like mold spores, which pose hazardous health risks.

Read: How Do You Know If You Have Poor Indoor Air Quality?

Media Filters

Media filters ensure a more effective air-cleaning process than standard filters. They have a large surface area. This allows them to work as effectively as units using high MERV (Minimum Efficiency Reporting Value) ratings.

Media filters clean the air without affecting static pressure or airflow.

Washable HVAC Filters

Washable HVAC filters can be an excellent option to cut costs and conserve the environment.

You can wash these filters and reuse them multiple times, saving you money in the long run.

 Additionally, washable HVAC filters can help reduce waste because you won’t have to dispose of them as often.

Read: How To Improve Air Quality In Basement?

Pleated Filters

These are flat HVAC air filters made of disposable cotton-polyester blend paper. They are more effective than washable filters and have a 5-13 MERV rating.

Pleated filters can remove almost 100% of the large particles from your indoor air. Due to their surface area and density, these filters effectively filter:

  • Mold
  • Pet dander
  • Pollen
  • Bacteria

Now that you have seen the various HVAC air filters, which is the best type and why?

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Which Is the Best HVAC Air Purifier?

The best air purifier is the one most suitable for your needs.

All air purifiers have a MERV rating, which indicates their effectiveness on a scale of 1 to 20. So, if you want an air filter for domestic use, the ideal purifier rating should range between 5 and 8. 

Any air purifier with a MERV rating above 12 is ideal for use in commercial settings. Such purifiers are effective for carefully planned environments like factories, hospitals, and laboratories.

High-MERV-rated filters are usually tightly woven, and they restrict airflow, making your HVAC unit work harder to clean air. This attribute makes them unsuitable for residential use. This is because they incur more energy expenses, one of the significant problems associated with HVAC air purifiers.

Drawbacks to HVAC Filters

Installing an HVAC filter is a great idea. However, they aren’t perfect. Below are some of their disadvantages: 

HVAC Filters Use More Energy 

Tightly woven filters may work inefficiently. As a result, you may pay higher electricity costs when your air filter’s performance decreases.

In the case of system malfunctions, your HVAC unit will work harder to circulate air in and out of the appliance, and the harder it strains, the higher your energy bill.

HVAC Filters Can Reduce Airflow

Clogged air filters can lead to reduced airflow in your air purifier. As mentioned above, dirty air filters can strain your HVAC unit when cleaning the air. 

Be sure to check and clean your air filter regularly. Doing this will help keep your purifier running at peak performance.

HVAC Filters Can Decrease Indoor Air Quality

You may not expect this problem, but HVAC air filters can reduce air quality. I’ve written a detailed post on how to measure indoor air quality. Reading this article can help you to keep your indoor air quality healthy. 

The longer you take to clean or replace the filters, the more dirt accumulates in them. The unit will, therefore, significantly contribute to air full of impurities in the building, which is counterintuitive to what you bought it for.

HVAC Filters Can Cause Overheating Issues

Overheating is another setback you may encounter with your HVAC air purifier, and an overworked HVAC unit is more likely to overheat. This is because it works harder to clean air than it should.

If your HVAC air purifier overheats, it may shut off or work less effectively. To avoid this, clean the filter regularly and check the unit for flaws. You may also want to keep the unit in a cooler, well-ventilated area.


An HVAC air purifier is handy for cleaning the air inside a residential or commercial building. The system is designed with filters that eliminate contaminants from the air.

HVAC air purifiers come with varying filters, such as:

  • HEPA filters
  • Electrostatic filters
  • Ionizing filters
  • Ultra-violet filters
  • Media filters
  • Washable filters
  • Pleated filters

However, air purifiers also have challenges. Dirt accumulation in the filters leads to problems like overheating, and you may also pay higher energy bills because the machine overworks to clean the air in your home. To be safer, service the filters often to avoid these problems.