The author, poet and philosopher, Ralph Waldo Emerson, could very well have been talking about today’s green-building movement when he said, “This time, like all times, is a very good one if we but know what to do with it.”
Given the current economic conditions, many owners and designers question the added cost of building green. But some architects are taking a page from value engineering concepts that first surfaced in commercial construction in the 1970s. They are finding ways to incorporate green-building techniques and principles in construction without disturbing tight budgets.
Value engineering is a methodical effort to analyze designed building features, systems, equipment and materials to achieve essential functions at the lowest life-cycle cost without sacrificing performance, quality, reliability and safety. Two Connecticut architects have taken this concept to heart, designing and building homes that integrate cool roofing with solar rooftop technologies to deliver energy paybacks without raising the overall cost of construction.
Architect Kate Johnson of Norfolk, Conn., employed value engineering to define savings in planning her home so she could afford an integrated standing seam metal roof system that supports a solar photovoltaic laminate system for electricity, as well as a solar thermal system under the roof for hot water and heating.
The lightweight, flexible PV laminate material is integrated onto the surface of the standing seam panels. The entire solar thermal system is positioned between the attic roof and the outside roof covering of the steep-slope standing seam.
The standing seam panels heat purlins, which hold and heat a water/glycol mixture that is circulated through cross-linked polyethylene tubing and cycled through conventional heat transfer and distribution systems. Because the roofing material will radiate heat after it reaches a certain temperature, the system is self-regulating and prevents overheating and component damage when the system is inactive for extended periods of time.
During the summer months, the solar thermal system provides 100 percent of the home’s hot water needs. The PV laminate system has reduced Johnson’s energy bill 25 to 30 percent annually. That includes the energy bill for the main house, as well as a small cottage and another building on the property. All of this has been achieved with 800 square feet (74 m2) of standing seam roofing on the south roof with the solar thermal system running beneath it and about 700 square feet (65 m2) of PV solar laminate material on top of the roof.
A Penny Saved
Johnson took several steps to contain overall costs to allow her to afford these measures and ensure an energy payback. First, she replaced her original design for a brick and mortar fireplace with a wood burning stove. That change alone saved enough money to cover the cost of the two solar systems and improved the thermal mass by reducing heat loss common in traditional fireplace systems.
Next, she opted for a 2-inch- (51-mm-) thick panelized foundation system, replacing the original plan for a poured 9-inch- (229-mm-) deep foundation. The prefabricated system was lowered into place using a crane, immediately ready for mechanicals and finishing. Not only did the prefabricated system take significantly less time and labor to install than the traditional poured system but its superior R-value reduced the amount of heat loss that bleeds from a traditional poured system. Johnson installed radiant flooring that taps the solar thermal system for its heat and that can effectively supplement heating in the cooler months.
Costs were further lowered by using plaster instead of sheetrock for the interior walls of the house. Although the plaster was initially more expensive than sheetrock, the plaster was mixed with the colors planned for the interior walls, which saved money by eliminating the cost of materials and labor needed for painters as well as the installation of window trim which the plaster replaced. All of these measures were instrumental in reducing the overall cost of construction without sacrificing quality.
Barbara Putnam of Litchfield, Conn., lives about 8 miles (13 km) from Johnson. Putnam worked for an environmental research and education firm before starting her own design firm several years ago. Like Johnson, Putnam was seeking ways to incorporate integrated solar technology in the design of her own home. She inherited land 15 years ago and had designed and built a 1,700-square-foot (158-m2) office/studio and a garage on the site.
Six years ago, Putnam decided to build a 3,500-square-foot (325-m2) home with three bedrooms, 2 3/4 baths, a living room, kitchen and study and attach it to the studio. Like Johnson, Putnam was working with a budget. She wanted to incorporate a standing seam metal roof with rooftop solar PV laminates and a solar thermal system but her budget did not allow for the entire roof to have standing seam panels. Rooftop solar systems almost always face to the south, giving them maximum exposure to the sun’s rays. Putnam designed and angled her house so the south side would face the road running in front of the property. She kept her roofing costs down by limiting the standing seam to the south side of the structure where it could be used with the solar systems. At the same time, she specified less expensive shingles for the remainder of the structure which faced into a large open field that could not be seen from the road. In doing so, she was able to save money but give the aesthetic impression that the entire structure was covered in standing seam.
Ultimately, the standing seam segment occupies about 925 square feet (86 m2) of the steep slope roof with 242 square feet (22 m2) of PV laminates attached to a dormer on the roof. The solar thermal system installed under the dormer roof is not a high heat system; it was designed to preheat water for heating, hot water and cooking.
The house was completed in 2006 and by March of 2007 she had the integrated system fully operational and monitored. Based on comparisons to her utility costs before 2007, Putnam has been able to reduce her electricity bill by 50 percent during the summer and 40 percent throughout the course of a year. The solar thermal system she uses in tandem with propane heat and hot water helped her use 18 percent less propane during the heating season in 2007 and 37 percent during the same timeframe in 2008.
Leave a Trail
A third area resident used solar to address the issue of power availability and was able to save money as well. Kurt Steele restored and renovated his second home—an 1840s structure—and built a 26- by 26-foot (8- by 8-m), 2-story wood frame structure adjacent to the house. The addition serves as a two-car garage and studio loft for guests. Kate Johnson designed the addition.
“I was serendipitously interested in solar energy and Kate told me what she had in mind for the building,” recalls Steele. “There were several reasons to go with the standing seam roof and solar, but there was one overriding reason. We get three or four ice storms a year plus high winds that can take out the power lines. I wanted a backup for the propane heat and electricity in the building if the lines go down.”
Steele assessed different backup generators he could purchase and ultimately chose the PV laminates and the under-roof solar thermal system instead. “We don’t heat the loft in winter when we’re not there and the solar thermal system keeps the loft area moderately warm,” Steele says. “We have a system that can carry the critical loads of the house for two or three days if the lines go down.” Steele also notes that the integrated solar roofing system was about half the cost of an emergency generating system necessary to carry the critical load for the structure.
Emerson once wrote, “Do not follow where the path may lead. Go instead where there is no path, and leave a trail.” In the current economy, the inclination often is to tighten the belt. But that is no reason for architects and builders to limit their creativity. If an integrated solar metal roofing solution can best serve the performance, quality, reliability and life-cycle cost goals of your project, step off the path, do a little value engineering and leave a trail.
Kevin Corcoran is vice president of sales for the Western Region of Englert Inc. He has been involved in the metal roofing and rainware industry for nearly 30 years.