Developing Tools to Measure IAQ
A better building envelope and improved ventilation systems are important first steps in improving the problem. But without knowing exactly how good or bad air quality inside a home actually is, these problems can’t be measured. That’s why the Lawrence Berkeley National Laboratory is working to develop an IAQ scoring tool.
The scorer will function much like a HERS score. It will take a series of measurements conducted by a third party to determine the home’s IAQ rating.
“In the world of IAQ, there are lots of claims and statements made about air quality in homes. Builders can say pretty much anything, and consumers won’t know any different,” says Iain Walker, lead of the residential building group for Lawrence Berkeley National Laboratory. “The scorer will be a technically sound third-party measurement of indoor air quality.”
When developing new scoring systems, researchers typically use a relative score, meaning the score is relative to a reference home. For example, most energy scoring systems take energy ratings of a standard home and measure them against measurements from a comparison home to get the score. Because there is no current IAQ standard for researchers to use as a comparison, the Lawrence Berkeley National Lab is creating a rating system that’s absolute.
The score will depend on a number of house characteristics. Some will be more basic, like adhering to ASHRE Standard 62.2 for ventilation, which includes factors such as installing exhaust fans in bathrooms and kitchens. Another is using a system that dilutes indoor emissions with fresh outdoor air.
It also will take into account using building materials that are low emitting, like VOC paints and certified wood products that are low formaldehyde. A homeowner could get a higher score if the home includes a radon control system, carbon monoxide detector and a whole-house filtration system to remove indoor particles.
Particles are the number one pollutant in homes,” Walker says. “If you put in a good filter and have a control system that removes particles with heating or cooling, it would improve your score.”
The score also depends on moisture prevention. For example, a homeowner that seals the ground from the crawl space to prevent moisture entry would earn a higher score. Homeowners in humid climates would earn a higher score by installing a humidifier.
The score also could be affected by the layout of the home. “In most new construction, the house has a garage attached. We put things like cars, gasoline-powered lawn mowers, old cans of paints and chemicals in there,” Walker says. “If this is the case, homeowners can earn an improved score if they have done a good job of air sealing between house and garage.”
Walker believes sensors will soon be available that will measure pollutants inside a home, including formaldehyde, particle and moisture sensors. A home with these sensors would earn a higher IAQ score.
The tool is not yet available, but Walker believes the first version, which will be used for beta testing, will be available within the next year.