A solar electric and thermal system that makes fuller use of heat generated from the roof of a house is at the heart of energy-efficient and affordable homes that Meritage Homes started selling last week in a new community called Lyon’s Gate in Gilbert, Ariz. The eight floor plans available at the 210-homesite Lyon’s Gate range from 1,600 square feet to 3,000 square feet. But the real news is that their prices start at less than $180,000, which C.R. Herro, Meritage’s vice president of environmental affairs, attributes to the cooperation of the builder’s suppliers and other trade partners.
“For the past six months, we’ve been reaching out to every company we deal with to get them to understand our strategy to become a production builder of energy-efficient homes,” Herro tells BUILDER. “Our CEO [Steve Hilton] has a vision of what a large home building company can become, and the [trade partners] that bought into what we are doing all came in with lower profitability” so the house prices could be kept affordable.
Herro says the homes at Lyon’s Gate are Meritage’s first to achieve a Home Energy Rating index score of less than 30. They are distinguished by a number of energy-saving features. Those include 9-inch-thick high-performance walls, spray-foam insulation (supplied by DEMILEC) throughout the house, weather-sensing irrigation and water management systems, and an electronic home management system that allows owners to monitor their energy use.
But the nerve center of these houses, and what allows Meritage to claim they are 80% more energy efficient than a typical existing home, is a roof-mounted solar system called Echo, supplied by PVT Solar, that can both heat and cool the house throughout the year.
The system generates electricity from its solar panels. But it also captures and moves heat from those panels through an air cavity underneath the mounted system and through exhaust/intake vents on the roof to an energy transfer module that’s typically in the house’s attic.
That module, which contains an air filter, heat exchanger, and fan, pushes pre-heated air to a water heater as well as to vents throughout the house. At night, Echo cools the house by directing air flowing from the roof system to an air conditioner through a phenomenon that PVT Solar refers to as Radiative Night Sky cooling. All told, the system produces between six to eight air exchanges per day, according to the supplier’s website.
“The overall system makes more than four times the energy of an existing house,” claims Herro, who adds that the cost of installing this system and the houses’ other features are fully covered by the selling price.
Every one of Lyon’s Gate’s homes will be tested and certified by ResNET-certified inspectors. Salt River Project, one of the state’s largest power utilities, has already awarded Lyon’s Gate its SRP PowerWise Homes seal of approval, which recognizes that the houses exceed Energy Star’s base home standards. And it appears that Lyon’s Gate could serve as a model for Meritage’s future projects, in Arizona and elsewhere.
Herro says the concept will need to be adjusted to any respective market’s climate. “Nine-inch walls might be overkill in a more moderate area like San Diego. And in Denver, we’d have to take a different approach to returning thermal to the house,” he explains. However, Lyon’s Gate “is a pretty good indication of where we’re going,” he says, in terms of combining energy efficiency and affordability.
John Caulfield is senior editor for BUILDER magazine.
Learn more about markets featured in this article: Phoenix, AZ.