By Steve Spaulding,
NASHVILLE, TENN. — The Green Hills are a borough of Nashville, Tenn., near the I-440 loop. The eastern edge of the neighborhood is bordered by Lipscomb University (go Bisons!), and is filled with stately older homes, some dating back to the 1800s.
The upscale community has been seeing more and more green construction in recent years, just like the rest of the country. According to the National Association of Home Builders, more than half its members – who together are responsible for more than 80% of new home construction – will be using green design and construction practices to some extent by the end of 2007.
When the time came to build the five-and-a-half-bedroom house at 904 Estes in Green Hills, the owner turned to Mark Fenelon of Mossy Ridge Construction, a GC currently in the process of gaining LEED (Leadership in Energy and Environmental Design) certification.
"Mossy Ridge focuses on building energy-efficient homes," said Fenelon, "and this project was the perfect marquee for our green construction efforts."
These efforts included the industry's highest rated windows and a computer-modeled HVAC system with sealed and insulated ducts. When it came time to do the plumbing system, Fenelon turned to Frank Sullivan Jr. of Joe B. Sullivan & Sons Plumbing and Heating.
"We got the job through a referral," said Sullivan. "We heard how the owner was trying to put together a green house package, trying to use all EnergyStar appliances, and we've done some work like that."
Sullivan & Sons has been a Nashville institution since 1895 when Frank Sullivan Jr.'s great-grandfather founded the business. Today the 11-man, non-union shop serves much of the middle Tennessee area.
"We do about a 50-50 mix of residential and commercial work," said Sullivan. "Of that, it's about a 50-50 mix of new construction and major renovation/remodeling. So it's a pretty good mix."
In keeping with the high-efficiency plan for his house, the homeowner initially had some interest in a tankless water heater. Because tankless or on-demand heaters only heat the water as the system calls for it, they avoid the standby losses that can sap the efficiency from a system.
However, the higher capacity a system requires, the harder a tankless system has to work, and the more efficiency is sacrificed. The home on Estes, at nearly 5,000-sq.ft. and built to house a large family, meant that capacity was going to be an issue. If a family member was trying to take a shower while at the same time a load of laundry was being done, even a well-designed tankless system was going to struggle to keep up.
Sullivan's solution was to use a high efficiency water heater from A.O. Smith, the Vertex. Thanks to its heat exchanger design, the water heater can deliver 90% thermal efficiency From there, it was just a question of doing the math and showing the owner which was the better long-term use of energy.
"I wouldn't say I talked him out of the tankless design," said Sullivan. "I just showed him some numbers and he made up his own mind. Called me back in 30 minutes."
Sullivan & Sons installed two of the water heaters, each able to deliver 127-gal. of hot water in the first hour of use, with a recovery rate of 92-gal. per hour at a 90°F rise. The water heaters were power-vented through a wall using PVC pipe. A Grundfos circulating pump keeps the hot water moving through the system.
The entire job, including trim-out, took a two man crew two and a half weeks of work to finish. "We priced the job out at between $17,000 and $18,000," Sullivan said. "That 's not including the cost of the water heaters. Include those and it would probably drive the cost up over twenty grand."
The higher initial outlay should pay off in savings over the life of the water heaters, which makes building green fiscally, as well as socially responsible.