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This article continues our series of profiles about the Building America research teams—multidisciplinary industry partnerships that work to make high performance homes a reality for all Americans. This month’s article focuses on Advanced Residential Integrated Energy Solutions and NorthernSTAR Building America Partnership—leaders in research and practical resources for industry.
Advanced Residential Integrated Energy Solutions
Factory-built homes have historically been required to meet energy standards that are less stringent than current International Energy Conservation Code-based codes. Thus, the industry has evolved few cost-effective options for reaching ambitious energy-efficiency targets. For many owners of manufactured homes, energy costs can be as high as home payments; this suggests that improved efficiency could greatly enhance their quality of life. To achieve this, the ARIES team is creating and demonstrating new building designs and practices for manufactured homes that: (1) minimize costs; (2) can be successfully applied in a factory setting; and (3) substantially reduce energy use. ARIES is developing and testing envelope and space-conditioning technologies that will reduce energy use by 50%. The team is applying a collective impact approach, partnering primarily with manufactured home builders that together are responsible for 80% of the industry’s home sales. ARIES is also participating in ongoing manufactured home thermal standards development. The team won a Top Innovation award for its work with industry partners Southern Homes and Johns Manville Corporation for a new, manufacturing-friendly method of dense-packing blown fiberglass attic insulation. This simple solution increases attic insulation R-value and promises real hope for industry adoption. With widespread implementation, this technology could save homeowners more than 6 trillion Btu and $190 million by 2030. ARIES’ work with Southern Homes resulted in the first manufactured home built to DOE Zero Energy Ready Home standards, winning an Affordable Builder honor in the 2014 Housing Innovations Awards. This cutting-edge design features the dense-pack blown fiberglass solution, superior wall and floor insulation, and a mini-split heat pump with an innovative thermostat-controlled transfer fan design. The team’s strong support of this industry is reflected in TLP’s long-term alliance with the Manufactured Housing Institute and administration of the Systems Building Research Alliance, the factory-built housing industry’s research arm.
An ARIES survey of 100 public housing authorities (PHAs) nationwide indicated a strong interest in developing low-cost solutions that improve energy efficiency and can be seamlessly included in the refurbishment process between occupancies. To this end, the team developed and evaluated a set of standard unit turnover protocols that housing authority staff can use to make energy improvements. In a project with Islip Housing Authority, the team performed energy audits, developed a low-cost energy-efficiency measure package, and trained staff in the protocol application. The energy-efficiency measures cost $250 per unit and resulted in whole-house energy savings of 10%–15%. In another project, the team worked with Raleigh Housing Authority to determine the most cost-effective way to reduce duct leakage in its 1,723 low-rise housing units. A combination of injected foam sealant and manual sealing cost $700 per unit and yielded energy savings of 17%, or $300–$600/year. ARIES also worked with the Philadelphia Housing Authority to test and implement the energy-efficiency unit turnover protocols in 2015.
The team applies its expertise in domestic hot water, air distribution, and ventilation systems to help multifamily building owners and operators improve the energy efficiency of existing buildings and comply with local and state programs. For example, ARIES partnered with NeighborWorks America affiliate Homeowners’ Rehab, Inc. to improve the central hydronic heating system in a three-building, 42-unit housing development. The heating control systems were upgraded, which reduced energy use by nearly 20% with a payback for all three buildings of less than 3 years. In another study that involved a steam heating system, the team explored the effectiveness of thermostatic radiator valves to control space temperatures and reduce heating fuel use. This research provides valuable insight into common steam system imbalance and resident behavioral issues that should be addressed in conjunction with thermostatic radiator valve retrofits. The team’s study of mini-split heat pump feasibility in multifamily retrofits identified technical barriers, costs, benefits, and market potential and concluded that mini-split heat pumps present a viable retrofit opportunity for some low-rise to midrise multifamily buildings.
ARIES is currently planning projects with HFH affiliates throughout the country. The research will consist of developing and demonstrating ultra-high energy performance homes with very efficient and tight thermal envelopes; small-capacity, high-efficiency heating, ventilating, and air-conditioning equipment; and controlled ventilation. The ARIES team is working with HFH affiliates to formalize an information sharing and research process to accelerate the leap to building practices that routinely achieve 50% energy savings relative to standard code-compliant construction.
NorthernSTAR Building America Partnership
Exterior foundation insulation in homes saves energy and improves structural integrity, indoor air quality, and comfort. Building scientists endorse exterior foundation insulation as the best method to enhance the hygrothermal performance of new homes. But this approach can be costly and disruptive when applied to an existing home because it requires deep excavation around the entire house and can heavily impact the landscape and structures. NorthernSTAR’s innovative solution to this challenge is a cost-effective, minimally invasive excavationless exterior foundation insulation upgrade technique. This approach combines two mature technologies—hydrovac excavation and pourable insulating foam—into a new process that is proving to be up to 50% less costly and much faster than traditional excavation methods. The hydrovac technology cuts a precise 3- to 4-in. wide trench to a desired depth while it loosens and extracts the soil and slurry. Then the trench is filled with liquid foam insulation. This measure has broad market potential and is applicable to tens of millions of homes with uninsulated foundations. Homes with finished basements, expensive landscaping, and barriers such as stoops and porches, as well as homes in need of waterproofing, drain tile, or repair, could also benefit from this technology.
The team also investigated the performance of high-efficiency combination (combi) systems that simultaneously meet space- and domestic water-heating needs. For this study, the team created a combi system laboratory to identify proper system components, designs, operating parameters, and installation procedures to ensure field-installed systems are highly efficient. The laboratory also provided a place for contractors, utility representatives, weatherization agents, and codes officials to view the systems and become familiar with their installation. Also, the team monitored 20 homes to measure how combi systems performed compared to the previous systems. After a full year of monitoring, the team found that the combi systems saved 19% of natural gas usage for space and water heating and showed an annual average combined efficiency of 87%. Because these systems are new to the market, future research will focus on options to reduce on-site design and engineering, improve efficiency, simplify controls, and increase system capacity.
NorthernSTAR’s whole-house overcoat technique is an external insulation for existing houses that uses a peel-and-stick membrane as an air and water barrier and then layers of exterior rigid foam as the thermal barrier. It is applicable to foundations, walls, and roofs and has yielded air leakage reductions as high as 81%; whole-house leakage was reduced by 20%–60% when the roof alone was retrofitted. This technique supports the scientific basis of the advantages of foam sheathing, furthers the acceptance of this material by the codes community, and fosters understanding of installation best practices for the building industry. NorthernSTAR garnered a Top Innovation award for its overcoat technique.
The “Best of NorthernSTAR” demonstration project exemplifies the team’s goal to implement home performance upgrades while it educates and engages community and industry partners. In a renovation project with Urban Homeworks, NorthernSTAR will demonstrate its three capstone innovations—excavationless, combi, and overcoat—and initiate guidance for the affordable housing community to replicate these innovative technologies. The house will also be used as an educational resource and training site for housing program managers, contractors, and code officials. NorthernSTAR team lead Patrick Huelman emphasizes, “For me, the “Best of NorthernSTAR” project embodies what the Building America program is all about. Our team has moved these innovations from research in the laboratory through development, demonstration, and ultimately, deployment in a real-world home.”
In addition, the team is a strong supporter of the DOE Zero Energy Ready Home program. It provides focused education and training events in the Upper Midwest market to help builders recognize the value of high-performance homes. Through high-visibility events such as the Parade of Homes and a prominent exhibit at the Minnesota State Fair, consumers gain the needed awareness and confidence to demand these same high-performance homes. In the end, Zero Energy Ready Home success is achieved when a willing buyer meets a willing seller.
Read spotlights on other Building America teams on the Research Team page.