A Meta-Analysis of Single-Family Deep Energy Retrofit Performance in the U.S.

Less, Brennan

doi:10.2172/1129577

Cited by 7 publications

(9 citation statements)

References 31 publications

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“…Whole house mechanical ventilation systems were installed in only 13 of 24 projects and installation rates were roughly consistent with those found in the U.S. DER literature (Less and Walker, 2014). The mechanically vented homes in this study had tighter envelopes, with a median of 1.1 ACH50 compared to 6.1 ACH50 for homes without mechanical ventilation.…”

Section: Ventilation System Descriptions and Installed Performance Assupporting

confidence: 79%

Indoor air quality in 24 California residences designed as high-performance homes

Less

Mullen

Singer

et al. 2015

Science and Technology for the Built Environment

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Today's high performance green homes are reaching previously unheard of levels of airtightness and are using new materials, technologies and strategies, whose impacts on Indoor Air Quality (IAQ) cannot be fully anticipated from prior studies. This research study used pollutant measurements, home inspections, diagnostic testing and occupant surveys to assess IAQ in 24 new or deeply retrofitted homes designed to be high performance green buildings in California. Although the mechanically vented homes were six times as airtight as non-mechanically ventilated homes (medians of 1.1 and 6.1 ACH50, n=11 and n=8, respectively), their use of mechanical ventilation systems and possibly window operation meant their median air exchange rates were almost the same (0.30 versus 0.32 hr -1 , n=8 and n=8, respectively). Pollutant levels were also similar in vented and unvented homes. These similarities were achieved despite numerous observed faults in complex mechanical ventilation systems. More rigorous commissioning is still recommended. Cooking exhaust systems were used inconsistently and several suffered from design flaws. Failure to follow best practices led to IAQ problems in some cases. Ambient nitrogen dioxide standards were exceeded or nearly so in four homes that either used gas ranges with standing pilots, or in Passive House-style homes that used gas cooking burners without venting range hoods. Homes without active particle filtration had particle count concentrations approximately double those in homes with enhanced filtration. The majority of homes reported using low-emitting materials; consistent with this, formaldehyde levels were approximately half those in conventional, new CA homes built before 2008. Emissions of ultrafine particles (with diameters <100 nm) were dramatically lower on induction electric cooktops, compared with either gas or resistance electric models. These results indicate that high performance homes can achieve acceptable and even exceptional IAQ by providing adequate general mechanical ventilation, using low-emitting materials, providing mechanical particle filtration, incorporating well-designed exhaust ventilation for kitchens and bathrooms, and educating occupants to use the kitchen and bath ventilation.3

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Section: Ventilation System Descriptions and Installed Performance Assupporting

confidence: 79%

Indoor air quality in 24 California residences designed as high-performance homes

Less

Mullen

Singer

et al. 2015

Science and Technology for the Built Environment

Self Cite

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“…The results are summarized in Table 2. Like the LBNL meta-analysis released the same year (Less and Walker, 2014), this review paper highlights the reported energy savings from the projects, confirming that greater than 50% savings are possible, though with substantial diversity in results. The report includes best practices and lessons learned from specific retrofit measures, including attics, above grade walls, foundations, windows, mechanical systems, etc.…”

Section: Aceee Deep Energy Retrofit Reviewmentioning

confidence: 70%

“…It also examines other key topics, such as availability of financing, minimizing household disruption, and engaging home owners and occupants. This literature review builds on a similar review from several years ago (Less and Walker, 2014). The current review focuses on efforts in the intervening years.…”

Section: Table Of Tablesmentioning

confidence: 99%

“…Part of this study was to summarize the extant deep retrofit literature. The resulting report (Less and Walker, 2014) assessed the current state of DER performance in the U.S. using performance data gathered from the available domestic literature on 116 homes across varying climate zones. The value of the analysis for some metrics was hindered by data gaps and inconsistent reporting.…”

Section: Previous Lbnl Deep Retrofit Meta-analysismentioning

confidence: 99%

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Emerging Pathways to Upgrade the US Housing Stock: A Review of the Home Energy Upgrade Literature

Walker¹,

Less²,

Casquero-Modrego³

2021

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This review addresses whole home energy upgrades targeting deep energy reductions (i.e., Deep Energy Retrofits, or DERs), from 30 to >50% site energy savings. The intent of this work is to characterize how energy upgrade projects and programs have evolved and improved over the past decade, and to identify what changes are needed to drive expansion of the U.S. retrofit market in such a way that addresses carbon emission from buildings, improves resilience and upgrades the housing stock for the 21 st century. The topics covered in this review are wideranging, including trends in U.S. and European retrofit programs, measure costs (e.g., ductless heat pumps, heat pump water heaters, exterior wall insulation), emerging technologies, advancements in simulation tools, surveys of energy upgrade homeowners and practitioners, business economics (e.g., soft costs, gross margins), and health effects. Key changes in project design noted in this review include the: (1) electrification of dwellings with rapidly improving heat pump systems and low-cost PV technology, (2) shift away from high-cost super-insulation strategies and towards more traditional home performance/weatherization envelope upgrades, (3) recognition of the importance of when energy is used and from what fuel sources in terms of both energy cost and carbon emissions, and (4) emerging smart home technologies, such as batteries or thermal storage, smart ventilation and HVAC controls, and energy feedback devices. Promising program design strategies covered in this review include:(1) end-use electrification programs, (2) novel financing approaches (e.g., Pay-As-You-Save and local lender networks), (3) Pay-for-Performance incentive structures, (4) securitization of portfolios of upgraded homes as investment products, and (5) One-Stop Shop programs that integrate financing, project management, design and support services. In addition to these project-and program-innovations, the industry should adopt new project performance metrics, namely those for carbon, peak demand and energy storage, along with metrics characterizing resilience and health. Market drivers are needed to spur widespread energy upgrades in the U.S. housing stock, which will require valuation of DERs by the real estate industry, reduced project costs (in part by cutting soft costs), and projects designed to appeal to homeowners while being enjoyable and profitable for contractors.

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“…Several factors have coalesced over recent years that have brought the US to the point where decarbonization of home energy use is not just acknowledged but can also begin to scale up in existing homes. These include: (1) increased affordability of on-site electricity generation; (2) ongoing decarbonization of the electric grid; (3) improved heat pump performance for space conditioning and hot water, particularly in cold climates and existing home applications; (4) increased knowledge of the health and safety concerns about burning fossil fuels in homes; and (5) increased consumer demand for electrification and decarbonization [1].…”

Section: Introductionmentioning

confidence: 99%

Home Energy Upgrades as a Pathway to Home Decarbonization in the US: A Literature Review

2022

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This work aims to characterize how home energy upgrade projects and programs in the US have evolved over the past decade. It also identifies what changes are needed to drive expansion of the US energy retrofit market in such a way that addresses carbon emissions from buildings, improves resilience and upgrades the housing stock. This review focuses on whole-home energy upgrades, targeting deep energy retrofit savings of >30%. The topics we cover include trends in home electrification, US and European home energy upgrade programs, energy upgrade measure costs, business economics, and health effects. Key changes in project design noted in this review include: (1) the electrification of dwellings with rapidly improving heat pump systems and low-cost solar photovoltaic technology; and (2) a shift away from high-cost building envelope strategies and towards more traditional home performance/weatherization envelope upgrades. Promising program design strategies covered include: (1) end-use electrification programs; (2) novel financing approaches; (3) the use of carbon-based program and project metrics; and (4) “one-stop shop” programs. Based on the existing market barriers, we suggest that the industry should adopt new project performance metrics. Additionally, market drivers are needed to spur widespread energy upgrades in the US housing stock. Costs must be reduced, and projects designed to appeal to homeowners and contractors.

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A Meta-Analysis of Single-Family Deep Energy Retrofit Performance in the U.S.

Cited by 7 publications

References 31 publications

Indoor air quality in 24 California residences designed as high-performance homes

Indoor air quality in 24 California residences designed as high-performance homes

Emerging Pathways to Upgrade the US Housing Stock: A Review of the Home Energy Upgrade Literature

Home Energy Upgrades as a Pathway to Home Decarbonization in the US: A Literature Review

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