Protecting Indoor Air Quality, Part 1

Most home buyers want to think of their home as a refuge—the ultimate safe space. Unfortunately, the safety inside our walls is too often compromised by a threat we can’t see: poor indoor air quality.

According to the Environmental Protection Agency (EPA), a growing number of scientific studies are finding that the air in our homes, offices, and other buildings can be significantly more polluted than outdoor air, even in large cities. Given that most people spend 90 percent of their time indoors, offering customers a healthier home through high-quality indoor air can be a powerful motivation to buy a new home.

While the tight building envelopes found in today’s high-performance homes and buildings offer enormous potential for improved indoor air quality, comfort, and energy efficiency, if not properly accommodated for, a tight envelope can adversely affect air quality—which can have serious implications on residents’ health.

According to Merietta, Ga.-based UL Environment, Inc.—an environmental services consulting firm specializing in building materials—side effects from poor indoor air quality range from problems such as odor complaints to issues as serious as the development of asthma due to mold. In extreme cases, radon accumulation can contribute to cancer, and carbon monoxide exposure due to tight building envelopes and multiple combustion appliances can lead to death.

Fortunately, there are proven steps builders can take to ensure their high-performance homes offer superior indoor air quality—providing an amenity with the power to move prospective buyers off the fence and into a new, healthier home.

Note: This is Part 1 of a three-part series on indoor air quality. Next week, look for posts on steps you can take to improve indoor air quality in residential and commercial buildings.

Credit: Library of Congress

Two of the biggest benefits hidden in high-performance building are going unnoticed, says Dennis Creech, co-founder of Southface Green Building Services, an Atlanta-based education, research and consulting nonprofit organization. And they both tie into one word: callbacks.

The first, he says, stems from the fact that in standard residential building projects, often the only commissioning that happens is done by the plumber, who tests the pressure on the supply lines when they’re roughed in. “Most code inspections only look at a few elements, and they don’t have time to conduct commissioning,” he says. As a result, many costly jobsite problems—such as incorrect deliveries or improper installations—go unnoticed.

However, when a builder is engaging in a green building certification program, the commissioning required for that process uncovers these problems, he says, saving the builder from costly callbacks down the road.

The second hidden benefit Creech calls out is the design review process that high-performance building certifications require, which can save builders from mistakes that can affect both buyers’ comfort and the home’s efficiency. Creech points to ductwork as an example, noting that often the plumber and the electrician come into a house before ducts are installed, and “they take all the really good, easy-to-get-to framing cavities. The duct guys get the third choice and there’s not much left.” But while bends in plumbing and wiring don’t cause big problems, he says, every 90-degree turn added in ductwork results in as much lost efficiency as a 10 foot addition to the duct system.

Another common problem is uncomfortable bedrooms caused by inadequate return airflow. “The air supply goes into the bedroom, but the return is in the hallway. If you have carpeting in the room, it essentially stops the return airflow when the door is closed. Even if you undercut the door, your return becomes 1 inch by 3 feet,” Creech says.

However, because most green building programs require a design review, problems like these can be eliminated right from the start. That not only helps the builder avoid the headache of costly repairs afterward, but also creates happy customers willing to lend their recommendation to future potential customers. “Most builders are very dependent on word of mouth for marketing,” Creech says. “That helps pay for the high performance building.”

Raising the Home Building Bar

Almost every house Bensonwood Homes has put up for the last two years has surpassed the air tightness level required by Passive House standards. And the best part is, it’s been free. “That’s just good workmanship,” says Tedd Benson, the Walpole, N. H.–based company’s founder.

If you’re wondering how the mid-sized builder has worked that level of precision into their homes, the answer lies in getting back to basics.

“Almost every architect, when they were in school in Architecture 101, learned about Vitruvius,” says Benson, speaking of the 2,000-year-old Roman credited with authoring the first works on architecture. Benson and his team took a hard look at the Vitruvian Triad — when mandates that for architecture to be successful it must be at once functional, durable, and beautiful — and determined that “if Vitruvius was alive today …, he would probably recognize that energy is another important ingredient in all of design that shouldn’t be sacrificed.”

As a result, the team added a fourth element, frugality, to the list and named the new standard the Vitruvian Imperative. Bensonwood has held that standard up to their own processes to find efficiencies, such as their practice of cutting their building materials with a CNC machine, which accomplishes much of the precision that allows them to achieve their superior air tightness.

Benson is now holding that Vitruvian-inspired standard up to the home building industry and encouraging all participants to use it to raise home building’s baseline for performance.

“Historically we’ve sacrificed beauty and good energy performance for some basic function and called this the typical American home,” he says. For an example of what could be possible, he points to the auto industry. “Most people assume their car can go 100,000 miles and not require a lot of maintenance or high-cost repairs, so consumers have learned to expect that, whether they’re paying $15K or $50K for a car. The designs are good. Reliability is good. It’s a good value. In overall quality of design, structure, function and energy efficiency, homes are far behind what is possible to produce as an American standard.”

The hard part for individual builders, he says, is that the problem is industry-wide, which makes it difficult to achieve the economies of scale that would be possible if all parties were more committed to a higher standard of performance. But while changing the nationwide industry’s mindset may seem like an insurmountable challenge, the solution can start in opening a dialogue, he says. “We need to begin to demand it of each other. We need to aim higher.”