Green Homes—Heating and Air Quality

Educated Homeowners

To get that smooth merging of energy efficiency with a healthy, comfortable home, homeowners must learn more and demand more.

Just buying high-efficiency equipment does not solve everything. That’s a misconception, says Laura Capps, director of Residential Green Building Services for Southface in Atlanta. Southface is a nonprofit that promotes sustainable homes, workplaces, and communities through education, research, advocacy, and technical assistance.

“The equipment efficiency depends on several things,” she says, “including the equipment being appropriately sized for the home and occupant activities, properly installed with a designed duct system that has been sealed and insulated and properly maintained. The key is to make sure the equipment chosen will meet the load of the home without being oversized and that the ducts installed will distribute that air appropriately to each room. Frequently the HVAC unit is replaced and the older duct work is left in place, which can be a sufficient solution as long as the ducts are the right size, installed correctly, sealed with mastic and insulated.”

Rule-of-thumb calculations for sizing equipment—so many tons of air conditioning per square foot of living area, for example—are no longer enough. Each home’s heating and cooling loads vary with its window area, air leakage, insulation levels, orientation, shade, and more. 

Uhde says an HVAC installer needs to do three critical tasks:  perform an Air Conditioning Contractors of America (ACCA) approved Manual J load calculation, size the equipment based on the load calculation results, and provide a Manual D duct design. It’s important that homeowners be involved and educated since many contractors try to skip this step (even though most codes require it) and it is the most crucial step in the process. She says just asking for the Manual J is a good start.

HVAC in residential homes is changing and many contractors are still learning about what’s new. Homeowners can help educate themselves online. Some sites to check out include the LEED for Homes guidelines for new homes or the new ReGreen Residential Remodeling Guidelines. 

Working with reputable contractors such as those training through Home Performance with Energy Star; certified through North American Technician Excellence, a nationwide certification program to ensure that qualifying technicians have a core set of competencies; or through local green building programs, such as EarthCraft House®, a residential green building program of the Greater Atlanta Home Builders Association in partnership with Southface, also can be of help.