Showcase Home Features High-End HVAC
Efficiency Achieved Using an Air-to-Water Heat Pump, Radiant Heat, and Ductless Cooling
Dennis Cunningham, president, ActiveWest Development and ActiveWest Builders, knows a thing or two about sustainable building practices. With over 20 years of development and land use/urban planning experience, and a two-year term as president of the United States Green Building Council (USGBC) — Idaho Chapter, it is no wonder that his Meadow Ranch active adult community features numerous Energy Star and LEED Platinum- and Gold-certified homes.
While all the homes in Meadow Ranch are extremely energy efficient, one stands out, as it not only achieved LEED Platinum certification, but it served as a test home for a new air-to-water heat pump. In addition, the 1,500-square-foot home features radiant in-floor heat, an energy recovery ventilator, and ductless cooling, and was designed to use 90 percent less energy for heating than those built to meet local and state building codes.
Meadow Ranch fulfills Cunningham’s mission to combine green building with smart growth, creating a friendly, easily accessible, diverse neighborhood that cost-effectively utilizes land in an urban setting. Among the amenities at Meadow Ranch are organic community gardens, composting, low-maintenance yards, drip irrigation, and rain buckets at down spouts. Recycled, low-emission, and locally sourced materials were used during construction, and 95 percent of construction waste was diverted from landfills. These statistics were validated by the community achieving USGBC LEED-ND (Neighborhood Development) certification.
“Our strategy to build green was a natural fit to our development and building practices, and is an integral part of our business model because of the fundamental common sense and logic behind efficiency, durability, and the forward-thinking construction science of green building,” said Cunningham. “Because of the urban infill and smart location, it made sense to incorporate prudent building practices into Meadow Ranch that promote energy efficiency and sustainability while supporting the local economy.”
About 60 percent of the semi-custom homes in the Meadow Ranch community, ranging in size from 800-2,400 square feet, are already sold. The homes are built using recycled blown-in cellulose insulation; dual-glazed low-E windows; energy heel wall construction; and low-flow faucets, toilets, and showerheads. Based on independent testing, the homes have an average Home Energy Rating System Index (HERS) score of 46.
Every home in the community has in-floor radiant heat, with larger homes utilizing Lochinvar gas-fired boilers with indirect hot-water tanks or electric boilers with high-efficiency water heaters, and smaller homes feature gas combination tanks that provide both radiant and domestic hot water. All homes meet ASHRAE Standard 62 guidelines, with proper ventilation being achieved through the use of Panasonic exhaust fans and energy recovery ventilators (ERVs). Optional Mitsubishi ductless mini-split heat pumps are available to homeowners who desire cooling.
“Comfort has always been of primary importance to us,” said Cunningham. “No matter how energy efficient the home is, if it is not comfortable, then it is not meeting our objective. While there may have been a lower operational cost to go with forced-air furnaces, we believe there is a greater comfort level in a home with radiant heat. In addition, there is less dry air blowing around in the home, which is important to our clientele in the active adult community.”
In the LEED Platinum-certified test home, which was featured in the local Parade of Homes, Cunningham decided to install something other than a boiler. After discussing heating options with Scott Heaton, area manager, Western region, Daikin AC, Portland, Ore., he chose to test a 3-ton, Daikin Altherma™, low-temperature, split-system water-to-air heat pump, which would supply not only the radiant in-floor heat but also the domestic hot water (the unit can also provide cooling, however, a ductless mini-split was used instead).
“The Altherma reflected the sustainable energy theme of this project, as it does not add any CO2 emissions to the atmosphere, and it has an option to add solar thermal to the domestic hot water, which made it a perfect fit for the project,” said Heaton. “In addition, the Altherma utilizes a variable-speed compressor that responds with inverter technology to deliver just the right amount of energy needed throughout the home. Even at low or partial loads, the heat pump does not short cycle, because it responds with an outdoor reset function — another energy-saving feature — that automatically adjusts the leaving water temperature based upon outdoor temperature.”
Jake Albertson, president, Bighorn Plumbing and Heating Inc., Hayden, Idaho, was asked to install the Altherma unit, which was a first for him. “Our specialty is radiant in-floor heat, so we usually work with direct- and indirect-fired boilers. This was the first time I worked with an air-to-water heat exchanger, and it was a pretty straightforward installation. The piping is very similar to what we would use with a boiler, and the startup went very smoothly. I really enjoyed working on this project.”
The whole design was fairly simple, yet very well done, said Heaton. “The slab-on-grade home has a single heating zone, so there’s only one manifold in the closet in the utility room. The indoor hydrobox provides domestic hot water, with the water inside the 50-gallon storage tank primarily warmed up by thermal energy from the outside air. An additional 3-kW heating element in the tank is there for backup.”
While Cunningham states that the upgraded HVAC systems in the Meadow Ranch community may cost more than other homes, “It is not easy to just compare our homes with others. An example of this is the car industry — does one automaker’s cars cost more than the others based on baseline federal standards?” What is important, he noted, is that homeowners in the sustainable community are very pleased with the level of comfort in their homes and are enjoying lower utility bills. “Building green is the right thing to do for our environment, economic landscape, and our children’s future,” he said.
Publication date: 6/24/2013