Solar Today April 2013 : Page 24

case study Affordable Net-Zero-Energy in Outlying D.C. By minimizing construction and utility costs, the Nexus EnergyHomes community in Frederick, Md., offers low-cost living — quite a feat in metro Washington, D.C. By V. PAUL ZANECKI T he American homeowner today understands that owning a home no longer Incentives Make Net-Zero More Affordable has the inherent value it once did. Today’s new homes have to work much Renewable energy systems in a Nexus EnergyHomes duplex in harder to offer long-term value. The homeowner demands a home that offers Maryland are eligible for more than $21,000 in incentives. more — more of the latest energy-efficient features, more health and comfort Federal Tax Credits features, more high-tech features that reflect today’s information age and, just Geothermal HVAC System $25,735 (Cost) as important but most challenging for the builder, a home that is affordable. x 30% (Tax Credit Multiplier) We at Nexus EnergyHomes had just this in mind as we planned new, affordable $7,721 (Total Tax Credit to Home Buyer) housing in Frederick, Md. We spent more than a year researching energy-saving and energy-generating technologies before ever putting a shovel in the ground. Our goal: Photovoltaic System $25,940 (Cost) to design high-performance, net-zero-energy homes, saving homeowners thousands on x 30% (Tax Credit Multiplier) their annual utility bills, while minimizing construction costs. The result is our North $7,782 (Total Tax Credit to Home Buyer) Pointe community. Many North Pointe homes are priced at or less than $300,000 — a Additional Items $1,500 (Total Tax Credit to Home Buyer) considerable feat in the Washington, D.C., market. Total Tax Credits $17,00 3 This 50-lot, “GeoSolar” housing development featuring 24 duplex units, 19 town-homes and seven single-family homes is the nation’s largest concentration of National Maryland State Grants Association of Home Builders (NAHB) Emerald-certified homes. All of the North Geothermal HVAC System $3,000 (2013 Md. State Grant) Pointe homes have achieved NAHB Emerald Certification. At the Emerald level, the Photovoltaic System $1,000 (2013 Md. State Grant) NAHB’s highest rating for a residential green building, a building must incorporate Total Grants $4,000 energy savings of 60 percent or more. In addition, all Nexus homes are designed to Total financial incentives meet the ICC 700 National Green Building Standards at the highest certification levels. $21,003 for homebuyer Each house in North Pointe includes the following energy-efficiency features: r1IPUPWPMUBJDBSSBZ TJ[FEGPSUIFTQFDJėDIPNF&#0a;&#0d; r(FPUIFSNBMIFBUJOHBOEDPPMJOHTZTUFN&#0d; r&OFSHZ&#0e;SFDPWFSZWFOUJMBUJPOTZTUFN&#0d; We spent more than a year researching energy-saving and energy-generating r-&%BOE$'-MJHIUJOHUISPVHIPVU&#0d; r&OFSHZ4UBSBQQMJBODFT&#0d; technologies before ever putting a shovel in the ground. r)JHI&#0e;QFSGPSNBODFMPX&#0e;FXJOEPXT&#0d;BOE rTUSVDUVSBMMZJOTVMBUFEQBOFMT 4*1T&#0a;&#0f; Creating a Tight, Insulated Envelope The North Pointe development began when Nexus took over a Department of Housing and Urban Development (HUD) Hope Six revitalization project to construct new affordable housing where an aging housing project once stood. Recognizing that utilities make up a major part of the cost of home ownership, we studied how we could make North Pointe homes more affordable by reducing their utility costs. In 2012, Maryland residential customers paid an average of 9 percent more than the national average, according to the U.S. Energy Information Administration. The cost of electricity is projected to continue to rise over the next decade. Reducing utility expenses to the level of net-zero-energy consumption begins with a super-insulated building enclosure using SIPs. SIPs consist of an insulating foam core sandwiched between two structural facings, typically oriented strand board. SIPs are manufactured under factory-controlled conditions and can be fabricated to fit nearly any building design. They are extremely strong, energy efficient and cost effective. Most importantly, they minimize thermal breaks and enable superior insulation installation. Following the installation of the SIPs, we air-seal all penetrations, plates and seams 24 April 2013 SOLAR TODAY solartoday.org North Pointe was designed to maintain an environmentally responsible, quality-constructed, tranquil and secure standard of living amidst a revived “d “ owntown” location. Copyright © 2013 by the American Solar Energy Society Inc. All rights reserved. NEXUS ENERGYHOMES

case study

V Paul Zanecki

<br /> By minimizing construction and utility costs, the Nexus EnergyHomes community in Frederick, Md., offers low-cost living — quite a feat in metro Washington, D.C.<br /> <br /> The American homeowner today understands that owning a home no longer has the inherent value it once did. Today’s new homes have to work much harder to offer long-term value. The homeowner demands a home that offers more — more of the latest energy-efficient features, more health and comfort features, more high-tech features that reflect today’s information age and, just as important but most challenging for the builder, a home that is affordable.<br /> <br /> We at Nexus EnergyHomes had just this in mind as we planned new, affordable housing in Frederick, Md. We spent more than a year researching energy-saving and energy-generating technologies before ever putting a shovel in the ground. Our goal: to design high-performance, net-zero-energy homes, saving homeowners thousands on their annual utility bills, while minimizing construction costs. The result is our North Pointe community. Many North Pointe homes are priced at or less than $300,000 — a considerable feat in the Washington, D.C., market.<br /> <br /> This 50-lot, “GeoSolar” housing development featuring 24 duplex units, 19 town-homes and seven single-family homes is the nation’s largest concentration of National Association of Home Builders (NAHB) Emerald-certified homes. All of the North Pointe homes have achieved NAHB Emerald Certification. At the Emerald level, the NAHB’s highest rating for a residential green building, a building must incorporate energy savings of 60 percent or more. In addition, all Nexus homes are designed to meet the ICC 700 National Green Building Standards at the highest certification levels.<br /> <br /> Each house in North Pointe includes the following energy-efficiency features:<br /> • Photovoltaic array (sized for the specific home),<br /> • Geothermal heating and cooling system,<br /> • Energy-recovery ventilation system,<br /> • LED and CFL lighting throughout,<br /> • Energy Star appliances,<br /> • High-performance low-e windows, and<br /> • structurally insulated panels (SIPs).<br /> <br /> Creating a Tight, Insulated Envelope<br /> The North Pointe development began when Nexus took over a Department of Housing and Urban Development (HUD) Hope Six revitalization project to construct new affordable housing where an aging housing project once stood. Recognizing that utilities make up a major part of the cost of home ownership, we studied how we could make North Pointe homes more affordable by reducing their utility costs. In 2012, Maryland residential customers paid an average of 9 percent more than the national average, according to the U.S. Energy Information Administration. The cost of electricity is projected to continue to rise over the next decade.<br /> <br /> Reducing utility expenses to the level of net-zero-energy consumption begins with a super-insulated building enclosure using SIPs. SIPs consist of an insulating foam core sandwiched between two structural facings, typically oriented strand board. SIPs are manufactured under factory-controlled conditions and can be fabricated to fit nearly any building design. They are extremely strong, energy efficient and cost effective. Most importantly, they minimize thermal breaks and enable superior insulation installation.<br /> <br /> Following the installation of the SIPs, we air-seal all penetrations, plates and seams using Owens Corning’s EnergyComplete Air Infiltration Barrier with Flexible Seal Technology to minimize air infiltration. We chose the low-expanding sealant because it sprays on easily and foams in place, with no shaving required. It is safe to use around windows and doors because of its low expansion rate; and it applies easily in ceiling and floor penetrations, around ductwork and construction joints. To insulate and air-seal the closed attic space, we install zero-VOC open cell spray foam insulation on the underside of the roof deck. This ensures that all ducts and equipment are in conditioned space.<br /> <br /> In addition to creating a tight, insulated building envelope, we strive to orient the homes to optimize solar exposure and incorporate extended overhangs and porches in our home design. Other passive solar elements include roofing and wall insulation installed to minimize seasonal excessive heat gain or loss.<br /> <br /> Selecting Ultra-Efficient Mechanicals<br /> Once the home is insulated and air sealed, the HVAC system is properly sized for the location and construction. Nexus uses the ClimateMaster Tranquility Series geothermal system with sealed underground loop piping filled with circulating water and an ultra-high-efficiency heat pump. A ground source heat pump system saves energy and optimizes comfort. It was a great choice for energy efficiency, and it also was eligible for significant federal incentives.<br /> <br /> From Nexus’ inception, it has been our mission to build homes that combine sustainability and energy efficiency with features that also offer a comfortable, healthy living environment. In today’s nearly airtight home construction, indoor air quality is of increased importance. Our North Pointe homes incorporate low-VOC elements, including spray foam insulation, all adhesives (including SIP adhesive), waterproofing, carpets, plywood (flooring and roof sheathing), paint and drywall.<br /> <br /> As part of Nexus CleanAir Filtration System, we also install an energy recovery ventilator (ERV) in every home to ensure even temperatures and fresh air while conserving energy. Nexus uses the Broan 270 cfm ERV with HEPA filtration. Ducting is designed to provide maximum efficiency and air flow/ movement throughout the home. The ERV system re-circulates the filtered air through the home, removing 99.97 percent of indoor air particulates.<br /> <br /> Beyond standard filtration and ventilation, each of our homes features a two-chambered air purification system. The system, which uses advanced photocatalytic oxidation technology, virtually eliminates harmful airborne particles including viruses, mold and bacteria.<br /> <br /> Our water-heating system includes a desuperheater that uses excess heat from the geothermal heat pump compressor to preheat hot water for the home. An 80 percent energy-efficient natural gas-heated tank provides the rest of the water heating needs. In addition, Nexus installs U.S. Environmental Protection Agency (EPA) Water Sense-labeled faucets, showerheads and lavatories. This reduces the water usage within the home, resulting in better environmental performance and utility bill savings.<br /> <br /> Most of the North Pointe houses have a 4- to 5-kilowatt PV system. We have been installing REC Peak Energy Series rackmounted PV panels with micro-inverters. The panels use silicon produced in the United States. The PV systems are sized to produce zero or near-zero grid electricity demand on an annual basis.<br /> <br /> As Nexus develops, we continue to look for the best products to use in our homes. In March, we announced our partnership with the Dow Chemical Co. as the first homebuilder in the Mid-Atlantic region to offer the DOW POWERHOUSE Solar Shingle. The solar shingles use a copper indium gallium diselenide thin-film PV technology. The result is a solar shingle that installs like typical roofing materials and is a lightweight, durable residential solar application. Going forward, we plan to offer the POWERHOUSE Solar Shingles in upcoming Nexus GeoSolar Communities, including future homes at North Pointe.<br /> <br /> Cultivating a Low-Energy Lifestyle<br /> Each home at North Pointe is also certified as an ENERGY-STAR New Home, and has undergone the EPA’s strict requirements. Our homes include ENERGY STARqualified CFL and LED lighting throughout. ENERGY STAR appliances are standard. These appliances use 10 to 50 percent less energy than standard appliances, ensuring reduced utility bills and enhanced quality, durability and performance.<br /> <br /> In addition, we are a RESNET EnergySmart Builder committed to rating each home. The average HERS Index Score for a NEXUS EnergyHome is 25, or 75 percent more energy-efficient than the standard new home.<br /> <br /> North Pointe homeowners have access to the NexusVision Smart System, a proprietary interface for tracking their home’s PV system production and energy consumption online. From any computer or smart phone, homeowners can monitor their energy use, adjust climate controls, switch lights on or off and control their security systems. The energy dashboard provides historic and trend data, with graphs showing usage in kilowatt-hours or dollars by week, month and year. Also, the homeowner can see the total cumulative benefit of their net-zero community in terms of carbon and fossil fuel avoidance, or in equivalency terms, such as trees planted.<br /> <br /> Residents of the 12 completed North Pointe homes report that the homes’ geothermal, solar and mechanical systems are outperforming design projections. We find that’s primarily because homeowners are managing their energy consumption via the NexusVision Smart System. North Pointe homeowners are holding “utility bill social events,” where they compare their utility bill savings and trade strategies for reducing energy usage.<br /> <br /> Financial incentives beyond the reduction or elimination of power bills help make the homes even more affordable. Incentives can include federal tax credits, state grants/rebates/tax credits, and local incentives. As an example, the box on page 24 details the federal and Maryland incentives for a North Pointe duplex at this time. As shown, these incentives can save the homebuyer more than $21,000. (See “Incentives Make Net- Zero More Affordable.”)<br /> <br /> Beyond sensibly priced urban housing, North Pointe was designed to maintain an environmentally responsible, quality-constructed, tranquil and secure standard of living amidst a revived “downtown” location. It is located near major employers such as Fort Detrick, Frederick Memorial Hospital and the National Cancer Institute and some of Frederick’s preferred dining, entertainment, shopping and schools. All of these attributes make North Pointe a highly sought-after community.<br /> <br /> We are always evolving and improving. We know that all the individual components have to be closely quality-controlled, or the systems as a whole will not function at our high standard. Work in product analysis, construction staff training, continuing education and quality control keeps us on our toes. We understand we must continually innovate. As products and standards change, we will change with them.<br /> <br /> We are hugely proud of what we have been able to accomplish since our founding just five years ago, especially in the challenging housing economy. Earlier this year, Maryland Gov. Martin O’Malley singled out Nexus in his State of the State address, citing North Pointe as “the epitome of innovation and entrepreneurship.” It was generous of him to recognize our commitment to returning power to the homeowner, creating a more sustainable future and freeing us from rising energy costs. It emboldens us to charge on with even more vigor, to reach new heights in homebuilding innovation.

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