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At least 1,369 records · Page 76

Predicted Versus Actual Savings for a Low-Rise Multifamily Retrofit in Boulder, Colorado

To determine the most cost-effective methods of improving buildings, accurate analysis and prediction of the energy use of existing buildings is essential. However, multiple studies confirm that analysis methods tend to over-predict energy use in poorly insulated, leaky homes and thus, the savings associated with improving those homes. In NREL's report titled 'Assessing and Improving the Accuracy of Energy Analysis of Residential Buildings,' researchers propose a method for improving the accuracy of residential energy analysis methods. A key step in this process involves the comparisons of predicted versus metered energy use and savings. In support of this research need, CARB evaluated the retrofit of a multifamily building in Boulder, CO. The updated property is a 37 unit, 2 story apartment complex built in 1950, which underwent renovations in early 2009 to bring it into compliance with Boulder, CO's SmartRegs ordinance. Goals of the study were to: 1) evaluate predicted versus actual savings due to the improvements, 2) identify areas where the modeling assumptions may need to be changed, and 3) determine common changes made by renters that would negatively impact energy savings. In this study, CARB seeks to improve the accuracy of modeling software while assessing retrofit measures to specifically determine which are most effective for large multifamily complexes in the cold climate region. Other issues that were investigated include the effects of improving building efficiency on tenant comfort, the impact on tenant turnover rates, and the potential market barriers for this type of community scale project.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. The incidents related to rainwater leakage and condensation concerns. Condensation concerns have been extensively studied by others and are not further discussed in this report. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Field Performance of Heat Pump Water Heaters in the Northeast, Massachusetts and Rhode Island (Fact Sheet)

Heat pump water heaters (HPWHs) are finally entering the mainstream residential water heater market. Potential catalysts are increased consumer demand for higher energy efficiency electric water heating and a new Federal water heating standard that effectively mandates use of HPWHs for electric storage water heaters with nominal capacities greater than 55 gallons. When compared to electric resistance water heating, the energy and cost savings potential of HPWHs is tremendous. Converting all electric resistance water heaters to HPWHs could save American consumers 7.8 billion dollars annually ($182 per household) in water heating operating costs and cut annual residential source energy consumption for water heating by 0.70 quads. Steven Winter Associates, Inc. embarked on one of the first in situ studies of these newly released HPWH products through a partnership with two sponsoring electric utility companies, National Grid and NSTAR, and one sponsoring energy efficiency service program administrator, Cape Light Compact. Recent laboratory studies have measured performance of HPWHs under various operating conditions, but publicly available field studies have not been as available. This evaluation attempts to provide publicly available field data on new HPWHs by monitoring the performance of three recently released products (General Electric GeoSpring, A.O. Smith Voltex, and Stiebel Eltron Accelera 300). Fourteen HPWHs were installed in Massachusetts and Rhode Island and monitored for over a year. Of the 14 units, ten were General Electric models (50 gallon units), two were Stiebel Eltron models (80 gallon units), and two were A.O. Smith models (one 60-gallon and one 80-gallon unit).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Evaluating an Exterior Insulation and Finish System for Deep Energy Retrofits

Exterior insulation and finish systems (EIFS) are proprietary synthetic formulations that are applied to the exterior walls of buildings to serve as insulation and exterior cladding. The insulation thickness can vary from less than one inch to a foot or more. In this project the applicability of EIFS for residential deep energy retrofits was investigated through modeling and a case study home. The home was retrofitted using a site-applied four-inch-thick EIFS. Site-specific details were developed as required for the residential retrofit application. Site work and the costs of the EIFS system were documented. The demonstration home was modeled using Building Energy Optimization energy and cost analysis software to explore cost effectiveness of various EIFS insulation thicknesses in two climate locations.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Building America Indoor Temperature and Humidity Measurement Protocol

When modeling homes using simulation tools, the heating and cooling set points can have a significant impact on home energy use. Every 4 years the Energy Information Administration (EIA) Residential Energy Consumption Survey (RECS) asks homeowners about their heating and cooling set points. Unfortunately, no temperature data is measured, and most of the time, the homeowner may be guessing at this number. Even one degree Fahrenheit difference in heating set point can make a 5% difference in heating energy use! So, the survey-based RECS data cannot be used as the definitive reference for the set point for the 'average occupant' in simulations. The purpose of this document is to develop a protocol for collecting consistent data for heating/cooling set points and relative humidity so that an average set point can be determined for asset energy models in residential buildings. This document covers the decision making process for researchers to determine how many sensors should be placed in each home, where to put those sensors, and what kind of asset data should be taken while they are in the home. The authors attempted to design the protocols to maximize the value of this study and minimize the resources required to achieve that value.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Measure Guideline: Combustion Safety for Natural Draft Appliances Using Indoor Air

This Measure Guideline covers how to assess and carry out the combustion safety procedures for appliances and heating equipment that uses indoor air for combustion in low-rise residential buildings. Only appliances installed in the living space, or in an area freely communicating with the living space, vented alone or in tandem with another appliance are considered here. A separate Measure Guideline addresses combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage that use outdoor air for combustion. This document is for inspectors, auditors, and technicians working in homes where energy upgrades are being conducted whether or not air infiltration control is included in the package of measures being applied. In the indoor combustion air case, guidelines summarized here are based on language provided in several of the codes to establish minimum requirements for the space using simplified prescriptive measures. In addition, building performance testing procedures are provided by testing agencies. The codes in combination with the test procedures offer comprehensive combustion safety coverage to address safety concerns, allowing inexperienced residential energy retrofit inspectors to effectively address combustion safety issues and allow energy retrofits to proceed.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Measure Guideline: Combustion Safety for Natural Draft Appliances Through Appliance Zone Isolation

This measure guideline covers how to assess and carry out the isolation of natural draft combustion appliances from the conditioned space of low-rise residential buildings. It deals with combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage. This subset of houses does not require comprehensive combustion safety tests and simplified prescriptive procedures can be used to address safety concerns. This allows residential energy retrofit contractors inexperienced in advanced combustion safety testing to effectively address combustion safety issues and allow energy retrofits including tightening and changes to distribution and ventilation systems to proceed.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Combustion Safety for Appliances Using Indoor Air (Fact Sheet)

This measure guideline covers how to assess and carry out the combustion safety procedures for appliances and heating equipment that uses indoor air for combustion in low-rise residential buildings. Only appliances installed in the living space, or in an area freely communicating with the living space, vented alone or in tandem with another appliance are considered here. A separate measure guideline addresses combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage that use outdoor air for combustion. This document is for inspectors, auditors, and technicians working in homes where energy upgrades are being conducted whether or not air infiltration control is included in the package of measures being applied. In the indoor combustion air case, guidelines summarized here are based on language provided in several of the codes to establish minimum requirements for the space using simplified prescriptive measures. In addition, building performance testing procedures are provided by testing agencies. The codes in combination with the test procedures offer comprehensive combustion safety coverage to address safety concerns, allowing inexperienced residential energy retrofit inspectors to effectively address combustion safety issues and allow energy retrofits to proceed.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Community-Scale Attic Retrofit and Home Energy Upgrade Data Mining

The U.S. Department of Energy’s Building America research team, Alliance for Residential Building Innovation (ARBI), implemented a project to increase residential retrofits in Davis, California. The project used a neighborhood-focused strategy for implementation and a low-cost retrofit program that focused on upgraded attic insulation and duct sealing. ARBI worked with a community partner, the not-for-profit Cool Davis Initiative, as well as selected area contractors to implement a strategy that sought to capitalize on the strong local expertise of partners and the unique aspects of the Davis, California, community. Working with community partners also allowed ARBI to collect and analyze data about effective messaging tactics for community-based retrofit programs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Analyzing Design Heating Loads in Superinsulated Buildings

The U.S. Department of Energy’s Building America research team Consortium for Advanced Residential Buildings (CARB) worked with the EcoVillage cohousing community in Ithaca, New York, on the Third Residential EcoVillage Experience neighborhood. This communityscale project consists of 40 housing units—15 apartments and 25 single-family residences. Units range in size from 450 ft2 to 1,664 ft2 and cost from $80,000 for a studio apartment to $235,000 for a three- or four-bedroom single-family home. For the research component of this project, CARB analyzed current heating system sizing methods for superinsulated homes in cold climates to determine if changes in building load calculation methodology should be recommended. Actual heating energy use was monitored and compared to results from the Air Conditioning Contractors of America’s Manual J8 (MJ8) and the Passive House Planning Package software. Results from that research indicate that MJ8 significantly oversizes heating systems for superinsulated homes and that thermal inertia and internal gains should be considered for more accurate load calculations.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Implementing a Zero Energy Ready Home Multifamily Project

Building cost-effective, high-performance homes that provide superior comfort, health, and durability is the goal of the U.S. Department of Energy’s (DOE’s) Zero Energy Ready Home (ZERH) program. Building America research and other innovative programs throughout the country have addressed many of the technical challenges of building to the ZERH standard. The cost-effectiveness of measure packages that result in 30% source energy savings compared to a code-compliant home have been demonstrated. However, additional challenges remain, particularly with respect to convincing production builders of the strong business case for ZERH. The Alliance for Residential Building Innovation (ARBI) team believes that the keys to successfully engaging builders and developers in the California market are to help them leverage development agreement requirements, code compliance requirements, incentives, and competitive market advantages of ZERH certification, and navigate through this process. A primary objective of this project was to gain a highly visible foothold for residential buildings that are built to the DOE ZERH specification that can be used to encourage participation by other California builders. This report briefly describes two single-family homes that were ZERH certified and focuses on the experience of working with developer Mutual Housing on a 62-unit multifamily community at the Spring Lake subdivision in Woodland, California. The Spring Lake project is expected to be the first ZERH-certified multifamily project in the country. This report discusses the challenges encountered, lessons learned, and how obstacles were overcome.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

High-Performance Ducts in Hot-Dry Climates

Duct thermal losses and air leakage have long been recognized as prime culprits in the degradation of heating, ventilating, and air-conditioning (HVAC) system efficiency. Both the U.S. Department of Energy’s Zero Energy Ready Home program and California’s proposed 2016 Title 24 Residential Energy Efficiency Standards require that ducts be installed within conditioned space or that other measures be taken to provide similar improvements in delivery effectiveness (DE). Pacific Gas & Electric Company commissioned a study to evaluate ducts in conditioned space and high-performance attics (HPAs) in support of the proposed codes and standards enhancements included in California’s 2016 Title 24 Residential Energy Efficiency Standards. The goal was to work with a select group of builders to design and install high-performance duct (HPD) systems, such as ducts in conditioned space (DCS), in one or more of their homes and to obtain test data to verify the improvement in DE compared to standard practice. Davis Energy Group (DEG) helped select the builders and led a team that provided information about HPD strategies to them. DEG also observed the construction process, completed testing, and collected cost data.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Analysis of Illinois Home Performance with ENERGY STAR® Measure Packages

Through the Chicagoland Single Family Housing Characterization and Retrofit Prioritization report, the Partnership for Advanced Residential Retrofit research team characterized 15 housing types in the Chicagoland region based on assessor data, utility billing history, and available data from prior energy efficiency programs. Within these 15 groups, a subset showed the greatest opportunity for energy savings based on BEopt Version 1.1 modeling of potential energy efficiency package options and the percent of the housing stock represented by each group. In this project, collected field data from a whole-home program in Illinois are utilized to compare marketplace-installed measures to the energy saving optimal packages previously developed for the 15 housing types. Housing type, conditions, energy efficiency measures installed, and retrofit cost information were collected from 19 homes that participated in the Illinois Home Performance with ENERGY STAR program in 2012, representing eight of the characterized housing groups. Two were selected for further case study analysis to provide an illustration of the differences between optimal and actually installed measures. Taken together, these homes are representative of 34.8% of the Chicagoland residential building stock. In one instance, actual installed measures closely matched optimal recommended measures.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Challenges of Achieving 2012 IECC Air Sealing Requirements in Multifamily Dwellings

While previous versions of the International Energy Conservation Code (IECC) have included provisions to improve the air tightness of dwellings, for the first time, the 2012 IECC mandates compliance verification through blower door testing. Simply completing the Air Barrier and Insulation Installation checklist through visual inspection is no longer sufficient by itself. In addition, the 2012 IECC mandates a significantly stricter air sealing requirement. In Climate Zones 3 through 8, air leakage may not exceed 3 ACH50, which is a significant reduction from the 2009 IECC requirement of 7 ACH50. This requirement is for all residential buildings, which includes low-rise multifamily dwellings. While this air leakage rate requirement is an important component to achieving an efficient building thermal envelope, currently, the code language doesn't explicitly address differences between single family and multifamily applications. In addition, the 2012 IECC does not provide an option to sample dwellings for larger multifamily buildings, so compliance would have to be verified on every unit. With compliance with the 2012 IECC air leakage requirements on the horizon, several of Consortium for Advanced Residential Building's (CARB’s) multifamily builder partners are evaluating how best to comply with this requirement. Builders are not sure whether it is more practical or beneficial to simply pay for guarded testing or to revise their air sealing strategies to improve compartmentalization to comply with code requirements based on unguarded blower door testing. This report summarizes CARB's research that was conducted to assess the feasibility of meeting the 2012 IECC air leakage requirements in 3 multifamily buildings.

2012 IECC↗

Internal Roof and Attic Thermal Radiation Control Retrofit Strategies for Cooling-Dominated Climates

This project evaluates the cooling energy savings and cost effectiveness of radiation control retrofit strategies for residential attics in U.S. cooling-dominated climates. Usually, in residential applications, radiation control retrofit strategies are applied below the roof deck or on top of the attic floor insulation. They offer an alternative option to the addition of conventional bulk insulation such as fiberglass or cellulose insulation. Radiation control is a potentially low-cost energy efficiency retrofit strategy that does not require significant changes to existing homes. In this project, two groups of low-cost radiation control strategies were evaluated for southern U.S. applications. One uses a radiant barrier composed of two aluminum foils combined with an enclosed reflective air space and the second uses spray-applied interior radiation control coatings (IRCC).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

The Building America Indoor Temperature and Humidity Measurement Protocol

When modeling homes using simulation tools, the heating and cooling set points can have a significant impact on home energy use. Every four years, the Energy Information Administration (EIA) Residential Energy Consumption Survey (RECS) asks homeowners about their heating and cooling set points. Unfortunately, no temperature data is measured, and most of the time, the homeowner may be guessing at this number. Even one degree Fahrenheit difference in heating set point can make a 5% difference in heating energy use! So, the survey-based RECS data cannot be used as the definitive reference for the set point for the "average occupant" in simulations. The purpose of this document is to develop a protocol for collecting consistent data for heating/cooling set points and relative humidity so that an average set point can be determined for asset energy models in residential buildings. This document covers the decision making process for researchers to determine how many sensors should be placed in each home, where to put those sensors, and what kind of asset data should be taken while they are in the home. The authors attempted to design the protocols to maximize the value of this study and minimize the resources required to achieve that value.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Evaluating an Exterior Insulation and Finish System for Deep Energy Retrofits

Exterior insulation and finish systems (EIFS) are proprietary synthetic formulations that are applied to the exterior walls of buildings to serve as insulation and exterior cladding. The insulation thickness can vary from less than one inch to a foot or more. In this project the applicability of EIFS for residential deep energy retrofits was investigated through modeling and a case study home. The home was retrofitted using a site-applied four-inch-thick EIFS. Site-specific details were developed as required for the residential retrofit application. Site work and the costs of the EIFS system were documented. The demonstration home was modeled using Building Energy Optimization energy and cost analysis software to explore cost effectiveness of various EIFS insulation thicknesses in two climate locations.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗