Filtration

The Importance of Air Filtration

The air filter in your furnace or air conditioner has a profound impact on your living environment. Regular filter maintenance is essential to maintaining proper indoor air quality (IAQ). Frequent filter changes can also improve energy efficiency and extend the life of mechanical systems.

The Benefits of Filtered Air:

• Removes dust, particulates and other airborne contaminants that adversely affect IAQ
• Reduces maintenance of building interiors such as frequent washings of blinds and fluorescent bulbs
• Protects the contents of occupied spaces including paintings, tapestries and other items of historic or cultural value
• Eliminates fire hazards by removing lint and other materials which might accumulate in ductwork

Air filters capture small particles of dust, pollen and other contaminants that ride on currents in the air stream. A well maintained filter, one that is regularly changed or cleaned, removes debris that might otherwise end up in your lungs. Some filters can clean more than 99 percent of airborne particulates. These high efficiency filters are important for the elderly, people suffering from asthma or allergies, and others with a compromised immune system.

Particle Sizes in Microns*

*American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Guide

When filters load with dust, they begin to create resistance against the airflow that can decrease overall system efficiency. That's why frequent filter changes or cleanings are so important. In fact, changing your furnace or air conditioner filter regularly can save you several hundreds of dollars a year in energy costs.

Failure to properly maintain air filters can have a devastating impact on your home's furnace or air conditioning mechanical system. Inadequate filtration allows for fine particles to collect on sensitive mechanical components, causing premature wear and breakdown. Regular filter maintenance can extend the life of your home's heating or air-conditioning system for years.

Duct Cleaning and Filtration:
In order to maintain clean air in your home or building, air filters must efficiently remove bacteria, pollens, insects, soot, dust, and dirt. Duct cleaning and filtration are linked together to achieve a complete indoor air quality solution.

Upgrading your filtration alone leaves existing contaminants in the duct system that can cause indoor air quality problems. Before upgrading to a better quality air filter, it is essential to ensure that the entire mechanical system is clean.

Duct cleaning without properly maintaining filters can accelerate the re-contamination of the HVAC system. Proper filter maintenance may extend the time between cleanings by keeping the system free of debris.

Which Filter is Right for Your Needs?
Filters are primarily used to remove airborne particulates to improve IAQ. The type and design of air filters determine the effectiveness of particulate removal, given the size and the amount of energy needed to pull or push air through the filter. Filters are rated by different standards and test methods such as dust spot and removal efficiency (which measures different aspects of performance). Ratings are provided by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), which is accredited by the American National Standards Institute (ANSI). ASHRAE develops standards for both its members and others professionally concerned with refrigeration processes and the design and maintenance of indoor environments.

To keep lint and dust from clogging the heating and cooling coils of a system, low efficiency filters (ASHRAE Dust Spot rating of 10 percent to 20 percent or less) can be used. To remove bacteria, pollens, insects, soot, dust, and dirt and maintain clean air in occupied spaces, medium efficiency filters (ASHRAE Dust Spot rating of 30 percent to 60 percent) are recommended.

Low-efficiency filters, if loaded to excess, become deformed and even "blow out" of their filter rack. This can lead to clogged coils, dirty ducts and the bypassing of unfiltered air. Air filters require regular maintenance (cleaning and replacement) regardless of the design or efficiency rating.

Filters should be selected for their ability to protect both the HVAC system components and general IAQ. Air filtration efficiency can be seriously reduced if the filter cells are not properly sealed to prevent air from bypassing. In many buildings, the best choice is a medium-efficiency, pleated filter because these filters have a higher removal efficiency than low-efficiency filters, yet they will last without clogging for longer than high-efficiency filters. Pleated-type extended surface filters are recommended to maintain proper airflow and minimize the amount of additional energy required to move air through high efficiency filters. In buildings that are designed to be exceptionally clean, the designers may specify the equipment to utilize both a medium efficiency pre-filter and a high efficiency extended surface filter (ASHRAE Dust Spot rating of 85 percent to 95 percent). Some manufacturers recommend high efficiency extended surface filters (ASHRAE Dust Spot rating of 85 percent) without pre-filters as the most cost effective approach to minimizing energy consumption and maximizing air quality in modern HVAC Variable Air Volume (VAV) systems that serve office environments.

To keep duct work clean, it is important to choose the correct filter for your home or building and properly maintaining the filter through cleaning and replacement. If dirt accumulates in ductwork and the relative humidity increases to the point that condensation occurs, then conditions may support the growth of biological contaminants such as bacteria and microbial growth.

DUCTZ professionals are certified, qualified and trained in duct and filtration maintenance and cleaning, helping extend the life and efficiency of your HVAC system while improving indoor air quality.

Contact your local DUCTZ office for more information.