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.


Building Education Pays Off in Performance

In discussions on high-performance building, a common refrain is that everyone involved needs to be onboard with the project’s goals and have the knowledge and skills it will take to achieve them. At Walpole, N. H.–based Bensonwood Homes, one of the company’s secrets to success has been taking that principle seriously.

“We strive to educate everyone [at Bensonwood] to be trained and educated in building science and building processes in things like wood technology and moisture management, and even architecture and engineering,” says Tedd Benson, the company’s founder. “People in building need to have a good basis in geometry and even trigonometry, for instance, and we try to make sure everyone has a good working knowledge in those areas.”

Why make such an investment in education? Because, Benson explains, once everyone on the project understands the principles behind high-performance building, they understand that every part of the building must work together for maximum efficiency.

To help team members with different skill sets understand the project as a whole, Benson taps into the knowledge-base of his staff. “The professionals on staff that have structural engineering in their background will do a 101 course for the rest of the staff,” he explains. “Once people understand the basic issues, when they’re in practice they know what the engineer is faced with and why we’re doing it that way.”

Bensonwood even has a curriculum for each department; the coursework and experiential aspects are so extensive that it can take five years to complete the program. The company also regularly invites in reps from manufacturers it does business with for seminars on how to get the best performance out of the products the builder puts into its homes.

Since Bensonwood does most of their construction off-site, they have the advantage of having their associates working in central facilities, which gives them more opportunities for classes or seminars to take place. “We can often be pretty effective with 15 minute ‘mini-seminars,’ which barely impact the production flow of the day,” Benson said. 

“To do anything well, it is first necessary to have the requisite knowledge and skills, and building is no different,” according to Benson. “In fact, we argue that this is one of the most challenging fields there is, and we have to find ways to provide the education and training that is otherwise not readily available in schools and other industry resources.”


How Much Can High-Performance Building Save Your Buyers?

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For high-performance home builders looking to leverage their homes’ efficiency, some new data from the U.S. Energy Information Administration (EIA) might be able to help.

Each year, EIA surveys the electrical power industry, collecting data that can be used to estimate the average monthly electric bills in each state. And that information can offer builders valuable insight on exactly how much money their homes and commercial buildings can save buyers compared to the local competition.

For example, in 2012 Hawaii had the unhappy distinction of achieving the highest average monthly electric bill for residential properties in the nation, averaging a whopping $203.15 per home each month. That is due largely to the fact that the Aloha State also ranks highest among average retail prices for electricity at 37.34 cents/kWh.

By region, the South Atlantic states have the highest electric bills, averaging $122.71 per month, while the Pacific states saw the lowest bills last year.

Given electricity’s price tag in much of the country, it’s little wonder that nine out of 10 home buyers would opt to pay 2 percent to 3 percent more for a home that had energy-efficient features and lower utility bills, according to a study conducted by the National Association of Home Builders earlier this year. However, for builders in areas where electric bills tips toward the high end of the scale, it’s likely that many buyers would be willing to pay even more. And as NAHB points out, these buyers would also likely be more interested in power-producing features such as solar panels.

House Frame

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.”

Where to Start with Sustainable Building

For Drew Smith — a home builder turned green building consultant and founder of Sarasota, Fla.–based green consulting firm Two Trails — the answer for why builders should be aiming higher than just hitting code mandates can be much simpler than an ethical imperative; it can be as simple as the fact that customers want it.

“Home buyers are gravitating to [sustainable] builders,” he says. “We can tell that by the interest.” Two Trails is averaging three new builder clients a month, who have never built green before, and Smith says it’s all market driven. The builders’ customers are asking for green, and “if they don’t do this, they’ll loose that sale.”

Part of that consumer-driven demand is fueled by improved awareness of the value green building can provide. “Customers know that higher SEER ratings impact energy costs,” Smith says. As a result, the industry standard in many markets has been raised, with energy-efficiency features now expected. Smith reports that in some colder climates, for example, triple-glazed windows are becoming more the rule than the exception. Such sea changes are raising the bar for all the builders in those markets, and especially for those trying to differentiate their product from the pack. 

For builders interested in taking a more sustainable approach to their projects, Smith advises that the best place to start is with the building envelope.

While people typically think of things like low-flow fixtures and energy efficient appliances — which certainly have value, particularly in customer recognition — those are features that customers can add in and improve on over time. Priority No. 1, Smith says, should be “the key features … that people can’t really afford to change later or improve on. Start out with the best envelope you can, and then the rest they can do later at a lesser cost.”


Green Roofs Come with Big Financial Benefits

Credit: Environmental Building Strategies

Most building projects tend to see their rooftops as a basic necessity rather than an extra amenity. But thanks to a growing awareness of the benefits green roofs can provide, that’s starting to change among a growing number of both residential and commercial builders, says Michael Hummel, sustainability architect at San Francisco–based Environmental Building Strategies.

It’s true that up-front costs are higher for a green roof. Hummel estimates that a simple system with grasses and small plants runs about $6 per square foot, whereas a more elaborate, food-producing system could cost $35 per square foot. Compared to the $1.50 per square foot cost of a traditional black asphalt roof, the price increase is significant. However, once the initial investment is made, Hummel says, the payback can add up to significant figures.

For starters, due to their improved insulation, green roofs can offer anywhere from a 50 percent to 75 percent reduction in cooling loads. And while the initial cost is higher, green roofs last longer, with a lifespan of 40 years or more, compared to a traditional roof’s 15- to 20-year lifespan.

And because green roofs improve the overall aesthetic of a building and increase its marketability, the Green Building Alliance estimates that a green roof increases a building’s value by anywhere from 6 percent to 15 percent.

In systems that include food production capabilities, a green roof can even generate cash flow through the sale of organic, hyper-local produce.

In fact, Environmental Building Strategies estimates that over its 40-year life, a 10,000–square-foot intensive food-producing roof would generate or save $4.3 million.

Even beyond the financial benefits, green roofs help remove airborne particulates and absorb CO2, reduce storm water runoff, and create outdoor living and community gathering spaces.

For builders and architects thinking about taking the plunge, Hummel offers a few tips for incorporating a green roof for the first time. “One of the most important things to consider with green roofs is the weight when the roof is watered,” he says. “The roof must be engineered to hold the additional weight and also have proper draining mechanisms to avoid flooding.”

Other vital systems for a successful project include soil moisture balancing mats, roof drain access hatches, puncture barriers, fertigation drip irrigation, perimeter root barriers, leak detection, and wind buffering.