One of the first homes to be certified net-zero, this modern energy-efficient home by Earthtone Builders in Asheville includes a 5.13 kW solar electric system.
As featured in our April 2016 newsletter:
NZEB is my new favorite acronym. If you haven’t come across it yet, you likely will soon, as Net Zero Energy Buildings (yes, NZEBs!) are the buzz in green building. NZEBs are built to balance out at net -zero in terms of their energy consumption, meaning the total amount of energy used by the building over the course of a year is offset by renewable energy production, which ideally is generated on site. The Kroner residence, recently constructed in West Asheville by Earthtone Builders (one of Asheville’s original green builders going back to 2003) serves as the epitome of a NZEB. This award-winning home was recognized as the most energy efficient home in the 2015 Asheville Parade of Homes, and also won Silver for Craftsmanship.
Achieving an impressive rating of 11 in the Home Energy Rating System (HERS) index, the nationally recognized industry standard by which a home’s energy efficiency is measured, means that this home is 89% more efficient than a standard new home. This rating warranted Green Built NC’s Gold level certification, and was accomplished by combining a highly insulated envelope with a hyper-efficient mini-split air conditioning system and radiant floor heating, along with other features such as clerestories for natural lighting. However, it was the inclusion of a 5.13 kilowatt solar electric (photovoltaic) system that earned the project net-zero certification, a new track for the Green Built NC program.
Including solar electric in a ‘spec’ home was part of Greg McGuffey’s (President of Earthtone Builders) intent to build a home that pushes the envelope in terms of design and energy efficiency so that others will be more confident in doing the same. “We want green homes with solar energy to be the standard, not the exception,” he said. Greg also emphasized the point ” that buyers are willing to pay for the extra cost of solar in the current Asheville home buying market. I think a lot of builders don’t know this and should have the confidence to make that a fundamental part of their packages.” In fact, this home ended up as a pre-sale, affirming the market demand for ZNEBs.
From most vantage points, the solar electric system is not very visible on the modern single level home. The array is flush-mounted to the corrugated metal roof in two sub arrays on either side of the shed dormer. In total, 18 SolarWorld Sunmodule Plus SW 285 watt modules comprise the system, which will produce an estimated 6,361 kilowatt hours of AC electricity in its first year. Their output is maximized by SolarEdge’s Power Optimizers and is made grid-compatible through a SolarEdge 5,000 watt 240 grid-tied string inverter. Through a net-metering agreement with Duke Energy, any electricity that is generated by the solar electric system that is not immediately consumed in the house is credited per kilowatt hour. This energy credit is available when energy is used from the grid at a 1-1 exchange. This annual agreement with the utility allows for the energy to be used as it is generated, whether it be by the home or somewhere else, and also means that the energy credit from periods of high production from the solar electric system (daytime, sunny days) is available during times of minimal production (nighttime or cloudy days) throughout the year. Greg reported that the last electrical bill for the home was a mere $5!
In another bold step in building for a more sustainable future, Greg said that they also installed an electric vehicle charger on the house, should the homeowner choose to purchase an EV. With the solar electric system and infrastructure in place, the transition to solar-powered transportation is set to be smooth.
As green building trends such as NZEBs become norms, our society has the opportunity to shift towards healthier, more sustainable living. It is encouraging to see that that new construction and the green building community here in our region is leading the progression. For more information, be sure to follow the many links throughout this feature.
Photography credit: Aubrie Shramko