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Guide to Closing and Conditioning Ventilated Crawlspaces

Description: This how-to guide explains the issues and concerns with conventional ventilated crawlspaces and provides prescriptive measures for improvements that will create healthier and more durable spaces. The methods described in this guide are not the only acceptable ways to treat a crawlspace but represent a proven strategy that works in many areas of the United States. The designs discussed in this guide may or may not meet the local building codes and as such will need to be researched before beginning the project.
Date: January 1, 2013
Creator: Dickson, B.
Partner: UNT Libraries Government Documents Department

Long-Term Results: New Construction Occupied Test House, Urbana, Illinois

Description: For this study, a house was designed and built to the Passive House (Passivhaus) Standard for low energy consumption. The house incorporates an airtight, super-insulated thermal enclosure, southern facing windows with overhangs, a single point mini-split heat pump and electric resistance heaters, and a balanced energy recovery ventilator (ERV). The house was instrumented with sub-metering on all major electrical circuits, temperature and humidity measurements in each room, domestic hot water consumption, and recovery efficiency of the ERV. The energy performance was documented and compared to modeled predictions, and the thermal comfort performance of the heat pump was assessed.
Date: October 1, 2012
Creator: Stecher, D. & Allison, K.
Partner: UNT Libraries Government Documents Department

IBACOS 2001 Final Technical Report: Building-Scale Project Results

Description: The focus of the IBACOS Building America Builder Program activities is working with builders to construct homes on a widespread basis that perform significantly better than their contemporary version and that advance residential building products and technologies. As part of the activities, performance goals are set for all homes in the areas of energy efficiency, indoor air quality, comfort, and durability. Integrated design, engineering, and construction-related work are conducted for each project. This work focuses on meeting the established goals through technical solutions.
Date: March 1, 2003
Partner: UNT Libraries Government Documents Department

Strategy Guideline: Energy Retrofits for Low-Rise Multifamily Buildings in Cold Climates

Description: This Strategy Guideline explains the benefits of evaluating and identifying energy efficiency retrofit measures that could be made during renovation and maintenance of multifamily buildings. It focuses on low-rise multifamily structures (three or fewer stories) in a cold climate. These benefits lie primarily in reduced energy use, lower operating and maintenance costs, improved durability of the structure, and increased occupant comfort. This guideline focuses on retrofit measures for roof repair or replacement, exterior wall repair or gut rehab, and eating system maintenance. All buildings are assumed to have a flat ceiling and a trussed roof, wood- or steel-framed exterior walls, and one or more single or staged boilers. Estimated energy savings realized from the retrofits will vary, depending on the size and condition of the building, the extent of efficiency improvements, the efficiency of the heating equipment, the cost and type of fuel, and the climate location.
Date: April 1, 2013
Creator: Frozyna, K. & Badger, L.
Partner: UNT Libraries Government Documents Department

Exterior Rigid Foam Insulation at the Edge of a Slab Foundation, Fresno, California (Fact Sheet)

Description: Exterior rigid foam insulation at the edge of the slab foundation was a unique feature for this low-load, unoccupied test house in a hot-dry climate and may be more appropriate for climates with higher heating loads. U.S. Department of Energy Building America research team IBACOS worked with National Housing Quality Award winner Wathen-Castanos Hybrid Homes, Inc., to assess the performance of this feature in a single-family detached ranch house with three bedrooms and two full bathrooms constructed on a slab-on-grade foundation in Fresno, California. One challenge during installation of the system was the attachment of the butyl flashing to the open framing. To solve this constructability issue, the team added a nailer to the base of the wall to properly attach and lap the flashing. In this strategy, R-7.5, 1.5-in.-thick extruded polystyrene was installed on the exterior of the slab for a modeled savings of 4,500 Btu/h on the heating load.
Date: October 1, 2013
Partner: UNT Libraries Government Documents Department

Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

Description: This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.
Date: November 1, 2013
Creator: Mittereder, N. & Poerschke, A.
Partner: UNT Libraries Government Documents Department

New American Home(R): Atlanta, Georgia--2002

Description: The New American Home is an annual showcase project designed by committee and co-sponsored by the National Association of Home Builders' (NAHB) National Council of the Housing Industry (NCHI). This year's project is built by John Wieland Homes and Neighborhoods and supported by IBACOS.
Date: January 1, 2002
Partner: UNT Libraries Government Documents Department

New American Home: Las Vegas, Nevada--2003

Description: The New American Home is an annual showcase project designed by committee and co-sponsored by the National Association of Home Builder's National Council of the Housing Industry (NCHI) and Builder Magazine.. This year it was a building project for Amland Development.
Date: December 1, 2002
Partner: UNT Libraries Government Documents Department

Strategy Guideline: Partnering for High Performance Homes

Description: High performance houses require a high degree of coordination and have significant interdependencies between various systems in order to perform properly, meet customer expectations, and minimize risks for the builder. Responsibility for the key performance attributes is shared across the project team and can be well coordinated through advanced partnering strategies. For high performance homes, traditional partnerships need to be matured to the next level and be expanded to all members of the project team including trades, suppliers, manufacturers, HERS raters, designers, architects, and building officials as appropriate. In an environment where the builder is the only source of communication between trades and consultants and where relationships are, in general, adversarial as opposed to cooperative, the chances of any one building system to fail are greater. Furthermore, it is much harder for the builder to identify and capitalize on synergistic opportunities. Partnering can help bridge the cross-functional aspects of the systems approach and achieve performance-based criteria. Critical success factors for partnering include support from top management, mutual trust, effective and open communication, effective coordination around common goals, team building, appropriate use of an outside facilitator, a partnering charter progress toward common goals, an effective problem-solving process, long-term commitment, continuous improvement, and a positive experience for all involved.
Date: January 1, 2013
Creator: Prahl, D.
Partner: UNT Libraries Government Documents Department

New American Home(R) 2006

Description: The New American Home(R) is a ''real-world'' laboratory demonstrating concepts, materials, designs, and construction techniques that can be replicated--in whole or in part--in housing built any place and in any price range. Since its inception in 1984, TNAH has the unique distinction of being both a show house and a for-sale product, balancing architectural freedom and the bottom line. It is a collection of ideas for the industry to take away and put into hundreds of thousands of homes across the country each year. TNAH 2006 was built with technical support from IBACOS and on-site support from IHP.
Date: November 1, 2005
Partner: UNT Libraries Government Documents Department

Measure Guideline: Transitioning to a Tankless Water Heater

Description: This Measure Guideline provides information to help residential builders and retrofitters with the design, specification, selection, implementation, installation, and maintenance issues of transitioning from tank-type water heaters to tankless water heaters. The report compares the differences between tankless and tank-type water heaters, highlighting the energy savings that can be realized by adopting tankless water heaters over tank-type water heaters. Selection criteria and risks discussed include unit sizing and location, water distribution system, plumbing line length and diameter, water quality, electrical backup, and code issues. Cost and performance data are provided for various types of tankless and tank-type water heaters, both natural gas fired and electric. Also considered are interactions between the tankless water heater and other functional elements of a house, such as cold water supply and low-flow devices. Operating costs and energy use of water distribution systems for single- and two-story houses are provided, along with discussion of the various types of distribution systems that can be used with tankless water heaters. Finally, details to prepare for proper installation of a tankless water heater are described.
Date: September 1, 2012
Creator: Brozyna, K. & Rapport, A.
Partner: UNT Libraries Government Documents Department

Long-Term Results from Evaluation of Advanced New Construction Packages in Test Homes: Lake Elsinore, California

Description: This report presents the long-term evaluation results from a hot-dry climate project that examines the room-to-room temperature conditions that exist in a high performance envelope, the performance of a simplified air distribution system, and a comparison of modeled energy performance with measured energy use. The project, a prototype house built by K. Hovnanian Homes' Ontario Group, is located in Lake Elsinore, Riverside County, California, and achieves a 50% level of whole house source energy savings with respect to the Building America (BA) Benchmark Definition 2009 (Hendron and Engebrecht 2010). Temperature measurements in three rooms indicate that the temperature difference between the measured locations and the thermostat were within recommendations 90.3% of the time in heating mode and 99.3% of the time in cooling mode. The air distribution system is operating efficiently with average delivered temperatures adequate to facilitate proper heating and cooling and only minor average temperature differences observed between the system's plenum and farthest register. Monitored energy use results for the house indicate that it is using less energy than predicted from modeling. A breakdown of energy use according to end use determined little agreement between comparable values.
Date: August 1, 2013
Creator: Stecher, D. & Brozyna, K.
Partner: UNT Libraries Government Documents Department

The New American Home 2007, Orlando, Florida

Description: Each year, The New American Home (R) demonstrates use of innovative building materials, cutting-edge design, and the latest construction techniques, providing production homebuilders with a model for producing more energy efficient, durable homes without sacrificing style. Cosponsored by The National Council of the Housing Industry and BUILDER Magazine, The New American Home (R) is not only the official showcase house of the annual International Builders' Show, but is also a for-sale product. The majority of features and innovations in the home are accessible to both builders and consumers for integration into their own homes.
Date: December 1, 2006
Partner: UNT Libraries Government Documents Department

Imagine Homes New Construction Occupied Test House

Description: This report summarizes the research findings of a long-term monitoring plan to evaluate the performance of an energy-efficient home constructed in 2010 in San Antonio, Texas. Monitoring of the energy use, energy generation, and temperature conditions for this project occurred between July 2010 and October 2011. The heating, ventilation, and air conditioning system effectively maintained acceptable temperatures and humidity levels in peak cooling and heating and non-peak operating periods. Discrepancies were found between modeled and actual energy use values, with actual space cooling energy use closest to the corresponding modeled value. Energy consumption predicted for lighting, appliances, and miscellaneous electrical loads was significantly higher than measured amounts, and energy consumption predicted for cooling was significantly lower than measured amounts. A high amount of the 1,600 kWh of PV-generated electricity produced annually was sent to the electric grid every month. The solar thermal DHW system was the main source of hot water for most of the year and performed well; during summer, electrical use by the backup system was rare.
Date: July 1, 2013
Creator: Stecher, D.; Rapport, A. & Allison, K.
Partner: UNT Libraries Government Documents Department

Inverted Attic Bulkhead for HVAC Ductwork, Roseville, California (Fact Sheet)

Description: K. Hovnanian Homes constructed a 2,253-ft single-story slab-on-grade ranch house for an occupied test house (new construction) in Roseville, California. One year of monitoring and analysis focused on the effectiveness of the space conditioning system at maintaining acceptable temperature and relative humidity levels in several rooms of the home, as well as room-to-room differences and the actual measured energy consumption by the space conditioning system. In this home, the air handler unit (AHU) and ducts were relocated to inside the thermal boundary. The AHU was relocated from the attic to a mechanical closet, and the ductwork was located inside an insulated and air-sealed bulkhead in the attic. To describe the performance and comfort in the home, the research team selected representative design days and extreme days from the annual data for analysis. To ensure that temperature differences were within reasonable occupant expectations, the team followed Air Conditioning Contractors of America guidance. At the end of the monitoring period, the occupant of the home had no comfort complaints in the home. Any variance between the modeled heating and cooling energy and the actual amounts used can be attributed to the variance in temperatures at the thermostat versus the modeled inputs.
Date: October 1, 2013
Partner: UNT Libraries Government Documents Department

Strategy Guideline: Compact Air Distribution Systems

Description: This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.
Date: June 1, 2013
Creator: Burdick, A.
Partner: UNT Libraries Government Documents Department

Comfort and HVAC Performance for a New Construction Occupied Test House in Roseville, California

Description: K. Hovnanian(R) Homes(R) constructed a 2,253-ft2 single-story slab-on-grade ranch house for an occupied test house (new construction) in Roseville, California. One year of monitoring and analysis focused on the effectiveness of the space conditioning system at maintaining acceptable temperature and relative humidity levels in several rooms of the home, as well as room-to-room differences and the actual measured energy consumption by the space conditioning system. In this home, the air handler unit (AHU) and ducts were relocated to inside the thermal boundary. The AHU was relocated from the attic to a mechanical closet, and the ductwork was located inside an insulated and air-sealed bulkhead in the attic. To describe the performance and comfort in the home, the research team selected representative design days and extreme days from the annual data for analysis. To ensure that temperature differences were within reasonable occupant expectations, the team followed Air Conditioning Contractors of America guidance. At the end of the monitoring period, the occupant of the home had no comfort complaints in the home. Any variance between the modeled heating and cooling energy and the actual amounts used can be attributed to the variance in temperatures at the thermostat versus the modeled inputs.
Date: October 1, 2013
Creator: Burdick, A.
Partner: UNT Libraries Government Documents Department

Hydronic Heating Coil Versus Propane Furnace, Rehoboth Beach, Delaware (Fact Sheet)

Description: Insight Homes constructed two houses in Rehoboth Beach, Delaware, with identical floor plans and thermal envelopes but different heating and domestic hot water (DHW) systems. Each house is 1,715-ft<sup>2</sup> with a single story, three bedrooms, two bathrooms, and the heating, ventilation, and air conditioning (HVAC) systems and ductwork located in conditioned crawlspaces. The standard house, which the builder offers as its standard production house, uses an air source heat pump (ASHP) with supplemental propane furnace heating. The Building America test house uses the same ASHP unit with supplemental heat provided by the DHW heater (a combined DHW and hydronic heating system, where the hydronic heating element is in the air handler). Both houses were occupied during the test period. Results indicate that efficiency of the two heating systems was not significantly different. Three issues dominate these results; lower system design performance resulting from the indoor refrigerant coil selected for the standard house, an incorrectly functioning defrost cycle in the standard house, and the low resolution of the natural gas monitoring equipment. The thermal comfort of both houses fell outside the ASHRAE Standard 55 heating range but was within the ACCA room-to-room temperature range when compared to the thermostat temperature. The monitored DHW draw schedules were input into EnergyPlus to evaluate the efficiency of the tankless hot water heater model using the two monitored profiles and the Building America House Simulation Protocols. The results indicate that the simulation is not significantly impacted by the draw profiles.
Date: January 1, 2014
Partner: UNT Libraries Government Documents Department

New Insights for Improving the Designs of Flexible Duct Junction Boxes (Fact Sheet)

Description: IBACOS explored the relationships between pressure and physical configurations of flexible duct junction boxes by using computational fluid dynamics (CFD) simulations to predict individual box parameters and total system pressure, thereby ensuring improved HVAC performance. Current Air Conditioning Contractors of America (ACCA) guidance (Group 11, Appendix 3, ACCA Manual D, Rutkowski 2009) allows for unconstrained variation in the number of takeoffs, box sizes, and takeoff locations. The only variables currently used in selecting an equivalent length (EL) are velocity of air in the duct and friction rate, given the first takeoff is located at least twice its diameter away from the inlet. This condition does not account for other factors impacting pressure loss across these types of fittings. For each simulation, the IBACOS team converted pressure loss within a box to an EL to compare variation in ACCA Manual D guidance to the simulated variation. IBACOS chose cases to represent flows reasonably correlating to flows typically encountered in the field and analyzed differences in total pressure due to increases in number and location of takeoffs, box dimensions, and velocity of air, and whether an entrance fitting is included. The team also calculated additional balancing losses for all cases due to discrepancies between intended outlet flows and natural flow splits created by the fitting. In certain asymmetrical cases, the balancing losses were significantly higher than symmetrical cases where the natural splits were close to the targets. Thus, IBACOS has shown additional design constraints that can ensure better system performance.
Date: January 1, 2014
Partner: UNT Libraries Government Documents Department

Passive Room-to-Room Air Transfer, Fresno, California (Fact Sheet)

Description: Field testing was performed in a retrofit unoccupied test house in Fresno, California. Three air-based heating, ventilation, and air conditioning (HVAC) distribution systems - a typical airflow ducted system to the bedrooms, a low airflow ducted system to the bedrooms, and a system with no ductwork to the bedrooms - were evaluated during heating, cooling, and midseason conditions. The relative ability of each of the three systems was assessed with respect to relevant Air Conditioning Contractors of America (ACCA) and ASHRAE standards for house temperature uniformity and stability, respectively. Computational fluid dynamics (CFD) modeling also was performed and refined based on comparison to field test results to determine the air flow rate into the bedrooms of over-door and bottom-of-door air transfer grilles.
Date: February 1, 2014
Partner: UNT Libraries Government Documents Department

Whole-House Approach Benefits Builders, Buyers, and the Environment

Description: This document provides an overview of the U.S. Department of Energy's Building America program. Building America works with the residential building industry to develop and implement innovative building processes and technologies-innovations that save builders and homeowners millions of dollars in construction and energy costs. This industry-led, cost-shared partnership program aims to reduce energy use by 50% and reduce construction time and waste, improve indoor air quality and comfort, encourage a systems engineering approach for design and construction of new homes, and accelerate the development and adoption of high performance in production housing.
Date: January 19, 2001
Creator: Hendron, B.
Partner: UNT Libraries Government Documents Department