Indoor air quality (IAQ) is a pressing national issue at the forefront of the HVAC industry’s effort to keep commercial and residential buildings safe, healthy and comfortable. Recent advances in building science have led to dramatic improvements in energy efficiency. In particular, tightening a building’s structural perimeter virtually eliminates air infiltration, which can dramatically reduce the indoor load and lower heating and cooling costs. Unfortunately, eliminating fresh air pathways can allow undesirable pollutants to accumulate in the living area where they contribute to dirty air and aggravate a variety of respiratory ailments.

What is Sick Building Syndrome?

The typical family generates or introduces a considerable quantity of contaminates into their home on a daily basis. This includes dander, smoke, hair, pollen, dirt, dust and other irritants. These toxins are cycled through the heating and cooling system repeatedly until they are unknowingly inhaled by one of the building’s occupants. Over time, continuing to breath polluted air can lead to the development of serious respiratory illness. Even short term exposure can worsen existing conditions like allergies and asthma. The problem is so severe that the EPA has classified indoor pollution and one of the top five environmental hazards.

While older homes usually have porous envelopes, they are not immune to the effects of poor indoor air quality. Leaky ductwork and structural perimeters can place the HVAC system into a negative pressure while operating. When the equipment is starved for air, contaminants in the attic or crawl space are drawn into the ductwork and blown directly into the indoor environment.

How to Improve Indoor Air Quality

Homes and commercial buildings with significant IAQ issues can be difficult to diagnose and remediate. HVAC professionals with the proper training and equipment incorporate a number of important components when developing a comprehensive strategy.

* Filtration: Central air filters play an essential role in correcting IAQ issues. Filters capture undesirable particulate matter as it passes through the air distribution system. Available in fiberglass, pleated and cabinet models, filters are usually mounted directly in the air handler or inside a hinged return air grille set in a wall or ceiling. The Minimum Efficiency Reporting Value (MERV) is a rating system developed by ASHRAE to provide consumers with an easy way to evaluate the effectiveness of different filter styles and models. Most HVAC professionals recommend installing a filter with a MERV value of 7-9, but it is important to confirm the system has the appropriate static pressure to accommodate a high efficiency filter before making the change.

* Ventilation: Mechanical ventilators compensate for the lack of natural air infiltration in tight homes by introducing a precise amount of fresh air calibrated to ASHRAE Standard 62.2. While a controlled amount of outdoor air is introduced into the living area, an equal amount of stale, contaminated air is exhausted. Some models include energy recovery features to help capture a potion of the energy lost in the air exchange process.

* Humidifiers: Maintaining a proper humidity level is important for keeping the indoor environment healthy. When the air is exceptionally dry, small contaminants stay airborne longer. Mucous membranes in nasal passages become excessively dry, and skin conditions may worsen. Wood furniture, doors and moldings can swell and split, and occupants may experience the effects of static electricity. Central humidifiers work in conjunction with the heating and cooling equipment to introduce moisture vapor into ductwork through steam or an atomized mist.

* Duct Cleaning: As air circulates through the HVAC system, dirt, dust and other debris accumulate inside the duct network. When combined with the moisture available at the evaporator coil, mold can begin to grow and proliferate. An HVAC system professional will employ an industrial-strength vacuum to clean the ductwork, which will help restore healthy IAQ and extend the life of your furnace and air conditioner.

* UV Lamp: Inside the evaporator coil, fungi, mold and other biological organisms flourish when exposed to moisture and other nutrients. UV germicidal lamps work at a specific wavelength to kill viruses, bacteria and other contaminates. A UV lamp will help keep your home cleaner and improve the efficiency of your HVAC equipment.

Why Healthy Indoor Air Quality Matters

Poor IAQ consequences can be severe if left unaddressed. There are a variety of conditions associated with contaminated indoor air including:

* Watering eyes
* Coughing and sore throat
* Rashes
* Difficulty breathing or wheezing
* Headaches
* Allergies
* Malaise and fatigue
* Asthma
* Severe lung disease
* Nose bleeds
* Upper respiratory congestion

Polluted indoor air also degrades HVAC equipment efficiency. Dirt and grime can coat the evaporator coil at the air handler. As a result, the equipment must cycle longer to meet the indoor load. This raises operating costs and can reduce the service life of your air conditioner and furnace. For complete IAQ solutions, always consult a licensed HVAC professional contractor.