Heating, ventilating and air-conditioning system (HVAC) balancing is the process of testing, adjusting and balancing HVAC components according to design intent. This ensures that equipment is installed and performing as intended.

Heating, ventilating and air-conditioning system (HVAC) balancing is the process of testing, adjusting and balancing HVAC components according to design intent. This ensures that equipment is installed and performing as intended.

Application: Optimal HVAC system design requires testing after installation to ensure optimal performance. It is especially important in homes with very tight construction to provide a means of supplying fresh, outside air, called makeup air, to replace that exhausted from the house. The system is balanced to maintain a slight positive pressure, so that indoor air is constantly flowing out of the home. This lowers the risk of accidental pollution of the home by contaminants from the combustion process itself, such as carbon monoxide and moisture.

Too much pressure, however, can force moisture into walls and crawl spaces, creating the risk of mold contamination and structural damage due to excess humidity. Balancing the HVAC system promotes optimal energy performance and ensures the system will perform as specified.

It also helps protect the home against contamination from within by furnace emissions and moisture accumulation, and contamination from outside by external sources. When replacing or adding HVAC equipment, consider having the system balanced after installation.

Benefits: System balancing reduces health risk to occupants of accidental exposure to contaminants. It protects against structural damage from moisture accumulation in structural cavities.

Challenges: System balancing costs more than conventional-practice system installations. HVAC system must be adjusted to provide balanced or slightly positive ventilation. At a minimum, this includes measurement of airflows, adjustment of outlets to design requirements and checking and setting the controls.

Information provided by Earth Advantage, an Oregon-based nonprofit organization that specializes in green building. Info: www.earthadvantage.com