Home Sustainable Land Development Today February 2007

Learning New Tricks

Written by Greg Yoko

Thursday, 01 February 2007

It’s never too late to stop, listen, and learn – no matter how much experience you have in the industry. Some builders and developers, as well as many others within the land development industry, could easily be classified as “old dogs” for their unwillingness to learn new techniques and practices. Fortunately, many have realized that to be successful in a competitive and changing marketplace, education about new trends, technology, and even tricks of the trade can make the difference between success and failure. Most of the recent building and development innovations are being driven by energy costs and environmental concerns. Product manufacturers and service providers are continually bombarding our industry with “new and improved” pronouncements. The difficulty for many practitioners, however, is finding or making the time to learn the proper application and implementation of these new and improved tools of the trade. Signed, Sealed, and Delivered Believe it or not, it really is possible to reduce building expenses while also providing a future reduction in the consumer’s home energy consumption. Brett Dillon operates Dillon Consulting in Chattanooga (TN). He specializes in sustainable construction and provides quality assurance inspections for builders. Most of his current work is on the sustainable side working on the building envelop as an energy rater with Home Energy Concepts, a dedicated Energy Star and Certified Home Energy Rating System (HERS) provider. He is also a frequent speaker on the topic of integrating building science into the homebuilding process. “My customers are pretty varied,” says Dillon. “Between 15-20 percent are homeowners who  want quality control on the homes they are buying, so I do home inspections and testing. The rest is an even mix between contractors and developers who view my services as a positive thing. They often rely on trade contractors and need someone to put another set of eyes on their project to make sure they received the quality of products and services they specified.” The photos accompanying this article, as well as the examples detailed, are from the Jefferson Heights development in Chattanooga. This is a sustainable urban infill development focusing on affordable housing. As a part of the purchase contracts for the lot(s), the contractors were required to hire an inspector, in this case Dillon, to ensure that the homes met EarthCraft house standards. According to one builder/developer, this is one of those situations where many long-time builders would rather stick with their experience. “I’ll tell you what, I didn’t believe in this at first,” admits William “Bo” Arthur of William Arthur Construction. “I saw the money end of it and thought I could do well on this project. But now I also see the advantage of building a quality home. “I think I can speak for 90 percent of the builders. We think we know the efficiency of the homes we build. But, until you go through a program like this, you really don’t. This is going to improve me as a builder two-fold and I am proud of that,” continued Arthur. “I have my son down here on this project, too,” Arthur said. “I know that when he leaves just this one subdivision, he’ll be a better builder than 90 percent of the builders out there because he is going to understand the true process of what it takes to build a good, quality, energy-efficient home.” According to Dillon, there are five practices that can significantly impact a builder’s construction costs as well as the homeowner’s energy costs: Sealed and conditioned crawl spaces Sealed and conditioned attics Properly sized HVAC units Properly design and installed duct systems Air sealing – tight construction Sealed and conditioned crawl spaces Dillon stresses that instead of using floor insulation under the lowest floor, the outside walls are what should be insulated. In addition to making a smaller envelope, it better seals the house because the numerous wires and pipes create “holes” in the floor. Practically speaking, it is much easier to keep wall insulation in place. “To be efficient and most effective, floor insulation is supposed to be in contact with the underside of the floor sheathing,” explains Dillon. “Gravity, however, starts pulling down the insulation immediately after it is installed.” Arthur, who has been a builder for 17 years, states that this was something that he had never done before. “There are certain things we can be stubborn about,” Arthur chuckled. “If I’ve been doing something for 17 years, I sure as heck don’t want somebody to come tell me how to do something different and have to admit to myself that I could have been doing something better all along. If you are not willing to learn, you cannot get better. Changing how I seal and insulate the floors and crawl spaces is going to save me about $600 per unit that I build – and it is a better home for the eventual owner.” Sealed and conditioned attics Likewise, Dillon says that his experience has shown that many attics are rarely sealed and properly conditioned. The problem, he states, happens because roofs are typically the first component of a house to be completed. Plenty of other systems are added with continuous access to the attic and roof occurring throughout the remainder of the construction process. In many instances, nobody takes the responsibility of checking that all access points have been sealed properly. Properly sized HVAC units Properly sized HVAC units is the “big one” according to Dillon. In fact, at the Jefferson Heights project in Chattanooga, most of these residential units had HVAC sizes cut in half. Understanding the basic process of determining the proper HVAC size is needed and very important. “Typically,” he explains, “HVAC vendors use ‘rules of thumb’ which usually have a 20 percent safety factor built into the calculations to account for their guess. Plus, it is sized for 99 percent of the highest/lowest temperature. Therefore, the initial calculations are commonly based upon 600 square feet per ton – which is completely inaccurate.” Big factors, he continued to explain, is that if the house is properly sealed, insulated, and conditioned, this reduces the size of the HVAC unit that is needed. Another reason for specifying larger units than are needed is because of windows. “Less than 10 percet of homes have load calculations,” Dillon claims. “So, most people use educated guesses, always going the perceived ‘safer’ route and choosing bigger units rather than smaller. A high performance building envelope has a direct impact on the load impact and typically is not considered.” Therefore, the calculation that was 600 square feet per ton is way off. On the Jefferson Heights project, it was almost 1,000 square feet per ton. Properly design and installed duct systems Dillon says that it is amazing how many times he finds homes where duct work was not sealed. The other area involving duct work is the size. “Most use 8-inch runs,” relates Dillon, “even going to an interior bathroom. It is usually a situation where the contractor is compensating for poor ductwork installation with more expensive and oversized HVAC equipment. Again, they would rather be safe than deal with comfort issues from the homeowner later.” Air sealing – tight construction In addition to neglecting to take the windows and duct work into load calculations, most HVAC people ignore the type of windows being used. “Window technology has come a long way in the past 10 years,” Dillon says, “but how many times does the HVAC contractor ever communicate with the window contractor on a job? Rarely ever. So how can the window quality be taken into consideration when the information is never relayed?” Dillon acknowledges that there are obvious differences when dealing with energy usage, home design and construction, and the various climates in the United States. But, he states that there are rating systems and standards for every location in the country. Using these procedures, as well as some additional measures, Dillon has documented instances where energy consumption was reduced by 5 million BTUs. LDT