WILMINGTON, N.C. - Mini-split HVAC systems have been gaining acceptance for residential add-ons, as well as commercial space reconfigurations. Their increasing efficiency and recognized flexibility is also making them more accepted in applications that typically go to central HVAC systems.
Anne & Bradshaw General Contractors Inc., Wrightsville Beach, chose “green build” as its strategic path several years ago. The company is recognized as one of the greenest homebuilders in North Carolina.
“We’ve never regretted the move,” said Pamela Fasse, general contractor and partner in the firm. “I’ve considered myself an environmental builder for many years, with a focus on energy efficiency and sustainability, but went all-out green about four years ago.”
Green strategies for the builder include low-imprint landscaping, high-efficiency HVAC, low-flow water fixtures, and non-CFC insulation.
“We feel it’s important to stay current with conservational techniques to minimize cost without sacrificing comfort,” said Fasse. “There’s a level of global responsibility at work, but we force ourselves to think locally. After all, as a home builder we’re apprised of new techniques and technologies before consumers are, and it’s right here at home where we can have the greatest impact.
“Going a bit more broadly, green construction aids in the preservation of our state’s fragile coastal ecosystems,” said Fasse and her partner and husband, Brad Karl.
The partners said, for the homeowner, the push for green translates to significantly lower energy costs; higher property values; cleaner, allergen-free living or working spaces; and low-impact technologies that provide beauty and efficiency with little maintenance.
DUCTLESS RESEARCHOne of the key contributors to the builder’s green-build approach has been the recent addition of ductless mini-split air conditioning and heat pump systems. “My husband and I were traveling in Asia last year, and we were amazed at the simplicity and efficiency of the systems, and how they were used everywhere,” said Fasse.
“Even at higher elevations in Japan, where it gets quite cold, mini-splits were meeting the comfort needs of what seemed to be every home and business.”
After Fasse returned from the trip, she looked into the availability of ductless systems here. “We did a lot of research after that trip,” she said. “What we found initially was that in this area there was very little experience with or knowledge about mini-split systems except on a one-room scale.”
Craig Chadwick, owner of independent rep firm Chadwick & Associates, Greensboro, learned through Bloomington’s Four Seasons HVAC that Fasse had an interest in learning more about the systems. Within a few months, their foray into a whole-house ductless mini-split applica- tion was under way.
“Chadwick was the critical link for us,” Fasse said. “They gave us a balanced view of how best to apply the technology, they did Manual J load calculations - the works. My husband and I settled on equipment manufactured by Fujitsu, a product line sold through Chadwick. We were especially impressed with the variable-speed Halcyon line.”
CONTRACTOR'S POV“We’ve done several whole houses, new construction, since about a year and a half ago,” said Walt Rager of Four Seasons. “We’ve been putting mini-splits in single rooms for about 10 years. Anne and Bradshaw had been looking at alternatives to standard central systems. They were bold enough to go with it.”
The chief benefits Rager perceives are “probably from a health standpoint,” he said; “there’s no ductwork for mold to grow in. From a comfort standpoint it can’t be beat,” he added. “It is zoning with a separate system for each zone. They’re extremely quiet, and the multi-zone system is 16 SEER equipment.”
The systems also handle the latent load efficiently, without the risk of oversizing the system, he said. “With the mini split and the Inverter technology, these systems are never oversized. If the whole system needs to run at 20 percent capacity, that’s what it runs.”
Getting the right refrigerant charge and line set length is the easy part, he said. “We have only used it on houses with spray-in insulation. It has to be a very tight house. It’s always worked in those applications.
“The one thing that has to be overcome is the public’s visual perception,” Rager said. “And it didn’t keep this builder from selling the house.”
The builder also installed several of the mini-split systems in homes they’ve built with the help of Don Lewis, owner of All Pro Services, an HVAC firm formerly based in Wilmington.
According to Lewis, the equipment offers ultra-high efficiency (up to 21 SEER and 10.0 HSPF); quiet, reliable operation; and sleek design. The line now includes 29 air conditioning and heat pump systems with capacities of 9,000-42,000 Btu, many also offering IAQ through plasma air filtration.
“The systems are ideal for heating and cooling, and they’re a great match to Anne & Bradshaw’s green-build emphasis,” said Lewis.
“Mix-and-match evaporators allowed me to create the perfect climate control for any size space.” This is especially important for homes whose size makes them on the small size for the smallest available central systems.
MINI-SPLIT FEATURESStandard features of the Halcyon units include wireless remote control, plasma filtration, a sleep timer, 24-hour timer, dry mode, auto louver, auto mode, quiet mode, auto restart/reset, auto changeover, and efficient operation with low or high ambient temperatures.
The coil dry mode helps inhibit mold and bacteria growth by reversing the cycle of refrigerant to dry out condensation in the indoor coil without changing room temperature.
During this mode, the plasma filter operates to help disinfect the coil. This feature is helpful in businesses where a system is shut off for the weekend, or for a vacation home that may be shut down for the season.
Ductless technology is typically applied for zoned cooling and heating, conditioning interior spaces right where it’s wanted. This technique saves energy by containing the heat or air conditioning. Other, lesser-used areas of the home aren’t cooled or heated unnecessarily. At night, energy dollars are saved by conditioning only the room(s) used at night, allowing temperatures to rise or fall in the rest of the home.
New mini-splits with variable-speed inverter technology have been in use for more than a decade in Asian and European countries; now they’re catching on in the United States as energy costs continue their upward climb. Inverter technology continuously modulates its energy production to match heat loss or gain.
A computerized logic module in the outdoor unit communicates with system sensors and the indoor unit. Together, the indoor and outdoor units continually monitor indoor and outdoor temperatures. Sensors feed this information to the logic module. If anything goes wrong, a fault code indicates what’s wrong with the equipment.
“That way, homeowners can often take care of minor issues without the need to call for service,” said Lewis. “Or, if a technician is needed, they can respond to more detailed fault codes with diagnostic equipment.”
“We’re glad that this manufacturer went with more-efficient R-410A and automatic inverter technology. Other suppliers stuck with R-22, which will be phased out in just three years,” said Rager.
Fasse said it can cost up to 10 percent more to build a green home than it does a conventional one. But ultimately, it costs less to live in them because of their greater energy efficiency and easier maintenance.
Fasse said the average monthly cost of electricity in her Parade home has been about $50, versus $200 in a conventional home. “Our homeowners are delighted with the technology, and so are we. We’ve now added a key new ingredient to our green home recipe.”
Sidebar: Jefferson HomeOne of the first homes in North Carolina to be built with whole-house, mini-split heating and cooling is believed to be the one constructed by Anne & Bradshaw General Contractors, Inc. on Jefferson Street in Wilmington, N.C.
Four Seasons HVAC installed two 36,000-Btu Fujitsu multi-zone systems in the 2,200-square-foot, cottage-style green home. At the end of July 2007, Pam Fasse, partner in the general contracting firm, received a call from the homebuyer.
“He called to tell me that he was completely satisfied with the system. He said there was no sound, and he was unaware of the air movement. Best of all, his July utility bill - our hottest month of the year, with a heat index of 110 degrees for more than a week - was less than $55. That included all electricity use, not just the home’s a/c.”
The home on Jefferson Street was completed in February 2007 and became an award winner in that year’s Wilmington Parade of Homes tour, including silver-level certification as an N.C. HealthyBuilt Home and the U.S. EPA’s Energy Star rating.
The certifications were clinched by the efficiency of the mini-split system, plus the use of spray-in foam insulation and sustainable and recycled materials, which earned high points.
Even recycled 4- by 8-inch Douglas Fir timbers, salvaged from turn-of-the-last-century warehouses, were used as structural components in the home’s design.