Library

Report describing the significant potential for energy use reductions through heat pump water heaters, which have been a crucial part of Northwest power plans for decades and have recently achieved substantial savings with new integrated models and climate specifications.

Report describing the features, benefits, and best practices for the design and installation of heat pump water heaters in new low-rise multifamily buildings, highlighting their efficiency, reliability, and contribution to decarbonization goals.

Report describing a laboratory assessment that provides insights into space requirements and venting strategies for heat pump water heaters (HPWH) to enhance retrofit installations and provide actionable guidance for manufacturers, designers, engineers, installers, and owners.

Guide providing detailed selection and installation instructions for heat pump water heaters.

Provides consumers with general information on solar water heating systems and how to select a contractor.

Case study of new home construction in the hot-dry and mixed-dry climate zones.

Best Practices document providing an introduction to current photovoltaic and solar thermal building practices.

Research study investigating the factors influencing consumer adoption of HEDs and evaluating the resulting electricity consumption.

Report on a project that enhanced the HWSIM distribution system model to more accurately model pipe heat transfer.

Article describing the factors that can lead to inefficient hot water distribution systems in homes.

Guide describing how to choose energy-efficient water heaters, including heat pump models, with tips on installation, rebates, and incentives for maximizing energy savings.

ENERGY STAR webpage describing how a heat pump water heater works.

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.

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 on on lessons learned from building one multifamily home to the Zero Energy Ready Home program requirements.

Report discussing the importance of durability and energy efficiency in building construction.

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.

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 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 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 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...

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

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

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

RESNET standards aimed to ensure that accurate and consistent home energy ratings are performed by accredited home energy rating providers through their raters nationwide.

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.

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.

Article describing key takeaways from two symposia held during Building Innovation 2016: The National Institute of Building Sciences Fourth Annual Conference and Expo, including that resilience can be affordable and cost-effective.

Research project aimed to verify whether homes in the New Jersey HPwES program achieved 30% source energy savings, and if so, what measures were implemented to achieve them.

Report discussing instrumentation methods and field operation characteristics of two GSHPs in test houses, including a comparison between the manufacturers listed COP values and the COPs calculated from field data.

Website with information and research about residential hot water distribution systems.

Brochure with information on residential solar hot water systems.

A retrofit sheet providing information on elevating and securing water heaters to protect against damage during a flood.

Report presenting results of a laboratory experiment studying combi systems as a mode to eliminate safety issues associated with natural draft appliances.

Information sheet describing tankless hot water heating systems in existing homes.

Document discussing changes in testing the annual performance ratings for solar water heaters.

A fact sheet providing homeowners with guidance on properly securing water heaters to prevent them from tipping in an earthquake.

Report comparing the performance of seven differing types of residential water heating systems in a side-by-side test configuration over a full year period.

Document about testing of seven water heating systems in the Hot Water Systems laboratory in central Florida.

Information sheet describing how to select a properly sized water heater based on household usage patterns, peak demand, and heater type—whether tankless, solar, or storage-based—to ensure efficiency and adequate hot water supply.

A website providing information on how to properly size a water heater based on tank size, volume, peak hour demand and other factors.