On a national basis, our country is suffering from an asthma and allergy epidemic. The annual healthcare costs of treating those with serious respiratory conditions are staggering, and there are other personal and financial consequences as well. It is no wonder that the EPA has consistently identified substandard indoor air as one of the five most damaging environmental hazards. As a result, leading-edge HVAC contractors have begun to address IAQ diagnostics and remediation in order to keep their customer’s indoor environment healthy and safe.

Why Indoor Air Quality is a Growing Problem

From the early 1990s through the late 2000s, the cost of energy continued to rise. To address the problem, the field of building science advanced rapidly, which led to extraordinary improvements in energy efficiency. In large part, perimeter building envelope leakage was eliminated through a variety of advanced sealing techniques. While creating a barrier against air infiltration has helped to dramatically reduce cooling and heating fuel consumption, the lack of fresh air pathways allows toxins and pollutants to accumulate inside the living area.

Understanding Sick Building Syndrome

On a daily basis, the average family introduces or generates a significant quantity of pollutants that settle inside the home. This includes smoke, dander, dust, dirt, pollen and a variety of other contaminants. These toxic agents are ultimately drawn into the heating and air conditioning system and cycled repeatedly until they are unwittingly inhaled by a family member. Constant exposure to airborne particulate matter can aggravate asthma, allergies and other breathing conditions. If your home does not have the technology required keep the indoor air clean, you may have Sick Building Syndrome.

Even older homes with porous building envelopes can suffer from poor indoor air quality. Prior to the adoption of national Model Energy Code standards, the duct work in a typical home was not properly sealed. When the blower engages in these homes, the system goes into a negative pressure, and dirt and fiberglass from the attic or crawl space are pulled directly into the air-stream.

Why Healthy Indoor Air is Important

Substandard IAQ can have harsh consequences if left unaddressed. There are a many serious medical conditions associated with contaminated indoor air:

  • Watering eyes
  • Sore throat
  • Chronic coughing
  • Difficulty breathing
  • Allergies
  • Wheezing
  • Respiratory congestion
  • Rashes
  • Headaches
  • Nose bleeds
  • Fatigue & Malaise
  • Asthma
  • COPD
  • Lung disease

Strategies for Improving Indoor Air Quality

Residential homes that have serious indoor air quality issues can be difficult to diagnose and remedy. It takes a professional HVAC technician who has the appropriate training and equipment to locate the source of the problem and correct it. In most cases, an effective IAQ strategy includes the following elements:

Central Filtration

The air filter inside your HVAC system is a critical IAQ component. Filters trap unwanted contaminants as they travel through the duct work. Filters are available in a number of different configurations, including pleated, fiberglass, electrostatic, electronic and cabinet models.

To determine the effectiveness of a particular filter, ASHRAE developed the Minimum Efficiency Reporting Value (MERV) standard. The MERV rating allows consumers to quickly compare the efficiency of different filter models and styles. A higher MERV rating always identifies a more efficient filter.

In general, a filter with a minimum MERV 7 value is recommended, but it is important to check with a licensed HVAC professional to determine if your equipment has sufficient static pressure to handle a high-efficiency filter.

Proper Humidification

Maintaining a steady humidity level is essential for a healthy indoor environment. If the air is too dry, microscopic irritants remain airborne for longer periods. Nasal passages can become dried out, and mucous membranes swell. Skin conditions may worsen, and wood furniture, moldings and doors can split and crack. 

Static electricity is another indication the air inside your home is too dry. A central humidifier works together with your heating and cooling system to introduce steam or atomized vapor into the air-stream to ensure the air is always properly humidified.

Conversely, a home that has too much humidity can create conditions that allow mold and fungi to thrive and grow. Black mold is a serious health hazard that must be immediately removed if detected. A dehumidifier unit can restore safe levels of moisture for homes in hot, humid climates.


Tight homes eliminate fresh air pathways, so it is important to provide mechanical ventilation to restore proper air exchange. Advanced technology ensures that the right amount of fresh air enters the home as an equal amount of stale indoor air is exhausted.

Newer models have a thermal recovery feature that recaptures a portion of the energy normally lost in the air exchange process.

Duct Cleaning

When the heating and cooling equipment is turned on, the air that travels through the system deposits dust, dirt and other debris inside the duct network. In combination with the moisture found at the air handler, mold and fungi have the nutrients they need to grow and spread.

Professional duct cleaning companies use brushes and air whips to loosen stubborn grime on the inside of the HVAC system, and an industrial-strength vacuum removes the debris and deposits it into a sealed container.

Ultraviolet (UV) Lamps

The evaporator coil inside an air conditioner is the perfect place for mold and other undesirable biological organisms to flourish. UV germicidal lamps are tuned to a specific wavelength that actually kills bacteria, mold, viruses and other contaminates.

A UV lamp can also help keep the inside of your HVAC system clean, which will improve efficiency and extend the life of the equipment.