Library

Report describing the identification of barriers and proposed practical solutions for the design, installation, and market adoption of heat pump water heaters in new low-rise multifamily housing, focusing on studio and one-bedroom units.

Report providing information about energy-efficient heating, ventilation, and cooling (HVAC) equipment options to help homeowners cut their energy use, reduce their carbon footprint, and increase their homes comfort, health, and safety.

Standards criteria supporting ICC HVAC duct support standards.

Report evaluating the relative effectiveness of various control and distribution strategies to improve hydronic space heating performance in existing low-rise multifamily buildings

Journal article presenting modeling of residential gas water heaters via dynamic simulation models to determine the effect of the pilot light on their annual energy consumption.

Report summarizing approaches to addressing duct leakage in hot humid climates.

Report describing the performance, economics, space heating impacts, and user satisfaction of heat pump water heaters (HPWHs) in the upper Midwest, based on a field study and survey of participants in the MECA HPWH incentive program.

Report showing installers how to attach ducts, pipes, and associated equipment to buildings to minimize earthquake damage.

Fact sheet describing principles of insulating steam distribution and condensate return lines as an effective way to prevent energy loss.

Report describing the objective evaluation of space conditioning interactions between heat pump water heaters and home heating systems during winter 2016-2017, revealing a smaller than anticipated impact on space conditioning loads.

This webpage provides an interactive walk-through of the installation of a heat pump water heater in a home in Massachusetts, including how-to videos of the installation, video interviews with the homeowners, installer, and utility program partners, and visual tours of the home before and after...

Report describing as-found interior platform return plenums, the magnitude of their contribution to the total amount of duct leakage, and techniques and results of retrofits executed by the HVAC trade during equipment replacement.

Report summarizing results of testing emerging combo water heating technologies under controlled laboratory operations, that differentiate the performance of the various packaged equipment configurations being offered.

Report presenting lab evaluation of five heat pump water heaters available in the US market today.

Report proposing mini-split heat pumps as a new retrofit option to replace resistance heating in the Pacific Northwest.

Report describing research conducted to support California’s Title 24, Part 6 Building Energy Efficiency Standards by analyzing the impact of installation location and ventilation on heat pump water heater (HPWH) performance, emphasizing the need for proper installation to maximize efficiency...

Report on the long-term performance of mini-split heat pumps.

Document presenting a cost effective method that was used by four builders in the Gainesville, FL area to construct interior ducts in over a dozen site built homes.

Report identifying the target market for solar water heaters and potential pathways and cost/performance targets that must be met for these systems to realize large energy savings.

This webpage provides an interactive walk-through of the installation of a heat pump water heater in a home in Maine, including how-to videos of the installation, video interviews with the homeowners, installer, and utility program partners, and visual tours of the home before and after installation...

Factsheet describing how to test the duct leakage of a manufactured home in the manufactured home factory.

Guidebook providing useful examples of high performance retrofit techniques for the building enclosure of wood frame residential construction in a cold and somewhat wet climate.

Document pertaining to design and application guidance for combination space and tankless domestic hot water heating systems used in residential buildings, based on field evaluation, testing, and industry meetings.

Report describing the installation and operation of forced-air heating and domestic hot water combi systems in residential homes.

Document intended for designers and installers of hydronic heating systems interested in maximizing the overall system efficiency of condensing boilers when coupled with baseboard convectors. It is applicable to new and retrofit projects.

Document with evaluation of 14 heat pump water heaters (including three recently released HPWH products) installed in existing homes in the northeast region of the United States.

Report providing guidance on how to implement a compact duct system inside a plenum truss bulkhead of a one-story, slab-on-grade home.

Report describing recommendations for optimizing flexible duct, constant-volume HVAC systems using junction boxes.

Document covering the technical aspects of buried and insulated ducts (BEDs), as well as the advantages, disadvantages, and risks of BEDs compared to alternative strategies.

Report describing the sealing and insulating of HVAC duct systems in existing homes.

Document illustrating guidelines for efficient installation of interior duct systems in new housing.

Document developed to help residential builders and retrofitters transition from tank-type water heaters to tankless water heaters.

Research study analyzing measured energy savings from a moderate retrofit by comparing post-retrofit performance with measured pre-retrofit monitored data.

Web resource that lays out the pre-work considerations, methods and finishes for installing mechanical insulation.

Standard that prescribes a testing method to determine the efficiency of space heating and/or cooling thermal distribution systems under seasonal and design conditions. This version of the standard was published in the year 2014, and is available for preview and purchase at the reference link. The...

This paper discusses model validation using data from three thermosiphon systems.

Report on the use of vapor diffusion ports to reduce moisture issues with buried ductwork in unvented attics in hot-humid climates.

Report detailing a three-winter study on unvented roof assemblies in a cold climate, assessing insulation material, ridge diffusion vent presence, vapor control membranes, relative humidity, and interstitial airflow. Results indicate that utilizing air-permeable fibrous fill insulations in unvented...

Report detailing a three-winter study on unvented roof assemblies in a cold climate, assessing insulation material, ridge diffusion vent presence, vapor control membranes, relative humidity, and interstitial airflow; results indicate that utilizing air-permeable fibrous fill insulations in unvented...

Conference paper making the case that moving ducts to conditioned space saves energy, is practical for production builders (when accompanied by careful pre-planning), and creates significant andmarketable energy savings for homebuyers.

Study in which a central heat pump water heater system was monitored in detail and used to create a model for assessing similar systems in various climates.

This report is designed to meet ASHRAE 62.2-2010/2013 and ANSI/ACCA’s 5 QI-2015 protocol, thereby improving the performance of HVAC equipment in new homes when compared to homes built to minimum code.

Guide providing information on controlling attic ductwork sweating.

Fact sheet describing a novel, simplified air delivery system using a plug-and-play model that features 3-inch diameter flexible ducts, efficient fittings, and a simplified installation process that resulted in successful market engagement through commercialization.

Document about development of recommendations to help residential HVAC designers select optimal supply inlet size and system operating conditions to maintain good thermal comfort in low heating and cooling load homes.

Research study using modeling to determine optimal combination(s) of components/pumps, high efficiency heat sources, plumbing configurations and controls that result in the highest overall efficiency for a hydronic system.

Report providing information to researchers, utility program managers, and building owners interested in controlling heating energy waste and improving resident comfort.

Article investigating how a linear input/output relationship can be used as a simple model of the performance of a combination hydronic heating system over heating only, DHW only, and combined loads.

Report describing the key findings from the first third-party field validation of 120-volt heat pump water heater (HPWH) technology, addressing the significant barriers to their adoption and emphasizing their potential role in reducing carbon emissions from residential water heating.

Report describing a laboratory assessment on the performance of Rheem 120-volt heat pump water heaters (HPWH), aimed at identifying optimal installation locations for these new "plug-in" models based on comprehensive testing under various conditions.