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Improving Your Home’s Indoor Air? Important Information for Maximum Quality

The U.S. Environmental Protection Agency (EPA) reports that residential homes can have some of the worst air quality of any other environment in this country. You can improve indoor air quality using specialized equipment that will remove many pollutants commonly found indoors. Before homes were built as tightly as they now are and homeowners sealed them tightly against air leaks, indoor air quality wasn't the issue that it is currently. 

Air filtration systems and indoor air cleaners are effective against organic pollutants, including pollen, dust mites, mold, bacteria and viruses, dust and pet dander.

Air cleaning and filtration systems won't remove some gases, like radon, carbon monoxide, some volatile organic compounds (VOCs) and indoor pesticide gases and odors, or odors associated with tobacco smoking. Ventilation equipment can reduce the levels of these indoor air hazards. 

Types of Air Cleaners

Mechanical air filtration systems can be installed into your central HVAC system or used for spot filtration as portable air cleaners. Which you choose depends on the extent of your indoor air quality issues. Before you select the equipment you need to improve indoor air quality, it might be a good idea to consult with your family physician and follow that visit up with a consultation with your HVAC provider who can steer you in the right direction for an air cleaner.

Types include:

  • Mechanical systems - These use filtration to trap airborne particles. Some of these offer better efficiency and convenience compared to portable cleaning or filtration systems. A central system will attach to your home's HVAC system and as it runs, the air blowing through it goes through a filter that prevents the particles from going into your home's air supply. 
  • Electrostatic air cleaners - These systems use an electrical charge to snare particles where they land on the charged plates. They remain there until the plates are cleaned. One of the advantages of electrostatic cleaners is that the air cleaner and the plates are permanent, unlike mechanical systems whose filters need replacement. 
  • Ultraviolet cleaning systems - These use ultraviolet (UV) lights inside the ductwork or inside the blower compartment to reduce the population of organic materials. UV light emanates naturally from sunlight, and these lights cause organic compounds to mutate so they can't reproduce. Homes with mold issues are good candidates for a UV light system, especially during the cooling system. These lights stop mold from growing inside the ducts and on the evaporator coil, improving the cooling system's energy efficiency. UV systems are common in healthcare facilities to reduce the spread of infectious diseases. 
  • Ventilation systems - If the thought of popping open a window periodically throughout the winter chills you, rest easy. The HVAC industry has developed an energy efficient way to improve indoor air quality with heat recovery ventilators (HRVs). These systems are balanced ventilators, bringing in as much fresh air as they exhaust. The core of the HRV contains technology that removes the heat from the exiting air and transfers it into the incoming air. 

    While this type of ventilation system will improve indoor air quality, it should not be used in place of carbon monoxide (CO) detectors. Carbon monoxide is one of the most dangerous gases you'll encounter indoors. If you use gas appliances or have an attached garage, it's important to keep a CO detector on each level of your home. Check the batteries monthly and replace when they fail to sound an alarm when tested. Radon mitigation through an HRV is possible, but you should work closely with the mitigation specialist you choose to make sure it's sufficient to safeguard your health

Filter Ratings for Mechanical Systems

Once you know what the worst particulate offenders for you or your family members are indoors, you can move forward with selecting a mechanical system that will trap those particles. Filters are graded by their minimum efficiency reporting value (MERV) rating, which describes the smallest particle the filter can trap. The scale runs from 1 to 16 for residential purposes, and filters rated over 8 offer the best entrapment. 

However, many HVAC systems can't use a filter with a MERV rating over 8 because they're simply too dense and will slow the airflow through the blower equipment. Most HVAC systems can get around this limitation with a whole-house filtration system that attaches to the ductwork and uses a separate fan to boost the airflow going into the HVAC system. 

High efficiency particulate air (HEPA) filters trap the most particulates and have MERV ratings that run from 17 to 20. They can arrest 99.9 percent of the airborne particulates over 0.3 microns. They're used in hospitals, clean rooms and health care centers. They require the most powerful fans to increase the airflow into the blower, since the filters are dense and slow the passage of air substantially. HEPA filters will trap all but the smallest tobacco particles but are ineffective against gases and odors. 

Getting the Most From the System

All of these systems require routine maintenance to run optimally and dependably improve indoor air quality. 

Mechanical systems need periodic filter changes. The installing HVAC contractor can tell you when to check and change the air filters. Ultimately, the frequency will depend on the particulate load indoors. Families with pets may need to check them more often because the amount of dust four-legged pets stir up can be high, especially in homes with hard surface flooring. The filter may also become covered faster if long-haired pets are under the roof.

Other factors dictating filter changes include:

  • Amount of dust created indoors - Most of the dust inside your home comes from dead skin and fibers from fabric, including all flooring materials, window coverings and furniture.
  • Severity of dust mite population - Dust mites thrive in environments with low humidity and where bedding isn't changed weekly. You can lower the dust mite population and improve indoor air quality by washing sheets in hot water and drying them in a hot dryer once a week.
  • Tightness of the windows - Drafty windows let in dust from the outdoors.
  • Number of home occupants - A larger household will generate more airborne particulates.
  • Frequency of floor cleaning - Many offending particles fall to the ground, and neglecting vacuuming will increase the amount of dust in the air. It's also a good idea to use a HEPA bag to reduce the amount of dust that seeps out of the vacuum cleaner bag. Over time, a HEPA bag will improve indoor air quality.  


UV lights need to be changed annually. As they run, the UV properties start to decline, leaving you vulnerable to the faster spread of mold spores, bacteria and viruses. Before changing the lights, be certain that you've turned the system off to prevent eye problems, since UV lights are damaging to eyesight. To prevent injury to hands, be sure the blower compartment is off when changing UV lights inside the blower. 

Electrostatic air cleaners don't need filter replacement, but they do require cleaning with soap and water to remove the trapped particulates. The frequency depends on the indoor particulate load, especially if there are smokers inside the home. If the plates fit inside your dishwasher, you can run them as a load, making sure they're thoroughly dry before reinstalling them in the frames. 

Ventilation systems like HVRs use filters to trap the incoming airborne particulates. These filters need to be cleaned or changed periodically. The owner's manual and the installing HVAC contractor can show you how to access and change them. 

To learn more about ways to improve your indoor air quality with filtration, purification and ventilation systems, contact Comfort24-7 today. We're proud to provide HVAC services for Chicagoland, northwestern Indiana and southeastern Michigan homeowners. 

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