Research

AEA innovates and sets aggressive benchmarks for carbon reductions in multifamily buildings.

Since 1994 AEA has been involved in a variety of advanced technology research and demonstration projects, primarily with funding support from the California Energy Commission, U.S. Department of Energy, New York State Energy Research & Development Authority (NYSERDA), and NYS Division of Housing & Community Renewal and others

  • REALIZE-CA: Mass Deployment Model for Zero Net Carbon Retrofits

    Low income Californians face a disproportionate energy burden spending up to three times as much of their income on energy compared to median households. Low-income multifamily buildings house more than three million Californians. At the same time, residential building stock in California currently accounts for approximately 10% of the state’s carbon emissions.

    Addressing these challenges has proven difficult due to a number of persistent barriers in the efficiency sector such as building owner mistrust in achieving savings, high upfront costs, project complexity and lack of industry know-how, split incentives between building owners and tenants, and a fragmented value chain.

    But the pressure is mounting, as California has set aggressive energy efficiency and carbon reduction goals enacting the policies necessary to achieve those goals. We can drive a sustainable manufacturing revolution by re-focusing efforts from building new, to rebuilding what we already have. California’s multifamily building housing market is the perfect place to start.

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  • Advanced Building Construction National Collaborative

    The Advanced Building Construction (ABC) Collaborative is a network of building construction, real estate, and development stakeholders that is accelerating the uptake of innovative, high-performance construction technologies that achieve superior energy and carbon performance, enable rapid on-site construction timelines, are affordable to building owners and developers, and are desirable to building owners and users.

    Industrialized construction refers to the practice of constructing all or part of a building at a site other than the building’s ultimate, permanent location. The initial (off-site) work location can provide a controlled environment.

    Prefab (i.e., prefabrication or prefabricated) refers to the practice of fabricating an assembly of parts and materials that will be installed as a package in the final building or at the final site. Modular construction refers to the practice of constructing standardized units in a manufacturing-environment (often full or partial volumes) that fit together to form the bulk of a building.

    All of these fit into the broader category of “industrialized construction,” which uses modern manufacturing techniques, controlled environments, and digital tools to increase labor productivity, quality, and consistency and reduce risk in construction. The Collaborative considers industrialized construction to be a key strategy in driving ABC.

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  • The Oakland EcoBlock, Phase II: A Zero Net Energy, Low Water-Use Retrofit Neighborhood Demonstration Project

    Buildings consume about half the energy used in the US; globally, buildings account for 39% of greenhouse gas emissions. Getting all buildings to net zero emissions is a critical task for climate change mitigation, but new building construction creates significant new emissions—typically two to four times more than renovations—and house by house retrofits are too slow. The adoption of energy efficiency (EE) and distributed energy resources (DERs) in the existing residential building stock is happening at too slow a rate to meet California’s aggressive energy and climate goals.

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  • Optimizing Water Heating Performance for Multifamily Zero Net Energy

    As California approached its 2020 ZNE goal, there was a critical need for more research and evaluation of ZNE multifamily design and construction practices, which were not explicitly addressed in the ZNE Residential Action Plan. In addition, as the carbon reduction opportunity of buildings is better understood, under-researched topics in multifamily buildings are receiving new attention. Although currently there are twice as many single-family residences as apartments in the U.S, multifamily is becoming a larger percentage of new construction. Therefore it is important to keep a focus on improving the efficiency and grid impacts of multifamily buildings if we are to achieve the State’s climate goals. Multifamily construction is more complex than single family and presents additional barriers to achieving ZNE and relatively little empirical data has been gathered on the performance of water heating systems in multifamily buildings, and even less on the energy use patterns for cooking, lighting, appliances and other plug loads. A host of key design and engineering, modeling and performance and operational issues remain poorly understood, particularly for emerging all-electric space heating and domestic hot water technologies. These include the performance and economic trade-offs of technology solutions, a lack of agreement between design and actual performance for key emerging technologies, appropriate modeling algorithms for emerging technologies, and a lack of understanding of how these technologies will impact tenants and property managers.

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  • Contra Costa Asthma Initiative

    Housing conditions play a significant role in health. It is estimated that Americans spend over 90% of their time indoors, and the majority of that time is in homes. Healthy homes are dry, clean, safe, well- ventilated, pest and contaminant-free, well-maintained, and thermally controlled. Deficiencies in any of these areas can lead to adverse health impacts. Public health has long recognized the nexus between housing and health. Perhaps most significant for health professionals, these reviews and studies point out that the health benefits of EE are greatest among those with pre-existing health conditions linked to housing risk, such as respiratory or cardiovascular diseases.
    The public health sector and the energy efficiency and weatherization sector operate in silos yet, there are many opportunities for stakeholders to support each other and create additional co-benefits for community members living in Contra County. Out of this opportunity was born the Asthma Initiative Program.

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  • Field Study of Wall Furnace Venting and Coincident Exhaust Fan Usage in 16 Northern California Apartments

    In the past several years, some consensus has developed around the belief that worst-case combustion safety testing of gas appliances is overly conservative and that it may result in many “safe” residences failing combustion appliance safety (CAS) inspections (Rapp, Less, Singer, Stratton, & Wray, 2015). These purported false-positives lead to reductions in the efficacy of energy retrofit programs, either through diversion of program funds towards remediation of perceived (but not real) combustion hazards, or by limiting energy-saving air-sealing in apartments deemed to be at risk of failing a CAS test. Many multifamily energy retrofit programs require that initial testing and remediation be performed before any energy retrofit work can commence; however, these programs do not provide the funding for the remediation work. As a result, it is not uncommon for otherwise strong energy retrofit candidate projects to drop out of these programs because they cannot, or do not want to incur the remediation costs.

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  • Indoor Air Quality in New and Renovated Low-Income Apartments with Mechanical Ventilation and Natural Gas Cooking in California

    Previous research completed by the Lawrence Berkeley National Laboratory has shown cooking to be a major contributor to indoor air pollutants in the home. While electric burners do produce some pollutants (ultrafine particles and some NOx), natural gas burners have been shown to be major contributors of these pollutants in addition to CO, CO2, formaldehyde, VOCs, and PM2.5 particles, all of which could have health implications. Sufficient ventilation could make the production of these substances a non-issue, however additional research has shown that typical kitchen hoods do not collect 100% of cooking byproducts, and are frequently misused or left unused. This concern is exacerbated in apartments, where the internal volume is smaller than a typical single family home, resulting in more rapid pollutant buildup. Title 24 standards have been updated to require continual ventilation, but it is unclear currently if this in addition to a typical range hood is sufficient to remove these contaminants from the air.

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  • Large Capacity CO2 Central Heat Pump Water Heating Technology Evaluation and Demonstration (LC-CO2 Project)

    While the market for low-GWP HPWHs is beginning to grow, there is still a dearth of products currently available in the U.S. that are appropriate for use in central water heating applications in multifamily buildings. To date the only low-GWP water heating product that has been readily available in the U.S. market is one that was not specifically designed for central system applications. As a result, each project has required customized configurations that are complicated from a design, installation and operation standpoint, and lack the types of staging control options and built-in monitoring and alarm capabilities that would make them ideal solutions for larger central system applications.

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  • Low-GWP Mechanical Modules for Rapid Deployment Project (LG-MM Project)

    One of the most substantial barriers in retrofitting a building is the amount of rework that must be done to a building’s interior, which becomes time-consuming, disruptive, bespoke, and costly. HVAC systems installed in existing buildings are often difficult to retrofit since the system components are spread throughout the whole building and installed in inaccessible locations such as behind floors or ceilings.

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  • Prefabricated Envelope Solutions for California Low-Rise Buildings

    Currently, envelope improvements are rarely part of business-as-usual renovation projects due to cost barriers caused by longer construction time when high performance windows, wall insulation, or recladding is installed on a building. This time, and therefore cost, barrier will be prohibitive in achieving all-electric, low thermal load buildings that will avoid excessive build out of the existing electric grid. To bypass the time-consuming, disruptive, bespoke, and costly envelope improvement processes, the Project Team will help develop unitized, prefabricated exterior façade panels that can be installed on an existing building in less than a week. A unitized panel includes windows, doors, exterior cladding, and air sealing such that once they are attached to the existing building, there is no other envelope work required.

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  • Integrated Mechanical System Pods

    One of the most substantial barriers in retrofitting a building is the amount of rework that must be done to a building’s interior, which becomes time-consuming, disruptive, bespoke, and costly. HVAC systems installed in existing buildings are often difficult to retrofit since the system components are spread throughout the whole building and installed in inaccessible locations such as behind floors or ceilings.

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  • Affordable Space Conditioning and Domestic Hot Water Systems with Low Emissions and High Performance

    Heating and hot water represent two of the top three energy uses for California households, just ahead of cooling. Most heating and hot water systems in California use natural gas, resulting in GHG emissions that are incompatible with California’s climate goals. California needs cleaner, more efficient electric alternatives, however, electric HVAC solutions currently available are expensive to purchase, install, and operate. They often require the use of separate heat pumps for heating and hot water, and typical operation patterns overlap with grid peak times, drive higher bills for ratepayers, electric grid system costs, GHG emissions, and air pollution. Conventional heat pumps also use refrigerants with high global warming potential. There is an urgent need for electric alternatives that pollute less, are affordable to install and operate, and are suitable for retrofits into existing and new homes, to allow large-scale adoption in California.

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  • Smart Ceiling Fans and Communicating Thermostats to Provide Energy-Efficient Comfort

    The electric peak demand in California is driven by summer-time air conditioning loads in residential and commercial buildings. Air conditioning has become a necessity in many climate zones: extreme heat events kill more Americans every year than any other weather-related disaster (US Department of Homeland Security 2020), and as climate change progresses, heat waves are increasing in intensity and frequency (Center for Climate and Energy Solutions (C2ES) 2017). Low income populations are increasingly more vulnerable as these communities often lie in areas disproportionately warmer than wealthier communities (Anderson and McMinn 2019), their houses tend to be less efficient (Berelson 2014), and they pay more of their income for energy (Alamo, Uhler, and O’Malley 2015).

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