Building America Technical Support

This report is an analytical investigation of the cooling delivery effectiveness of radiant ceiling panels at multiple insulation levels. Frontier Energy Inc. evaluated the performance of radiant panels with various levels of attic insulation to calculate the heat transfer rate between the ceiling radiant panels and the indoor space. The analysis showed that attic insulation of R-56 would be required to meet the 95% delivery effectiveness assumed by 2021 IECC for radiant celling panels with components outside the conditioned space, and an attic insulation value of R-79 would be required to meet 100% effectiveness if all components are inside conditioned space.

• Summary Report

This report examines residential sizing methods for variable-capacity heat pump systems in cold climates using Manual J-equivalent block load calculations and HVAC energy simulation results with EnergyPlus™ and identifies parameters to optimize system capacity and efficiency. For this analysis, Performance Systems Development evaluated the sizing methodologies including the effect of envelope improvements and solar and internal gains at different times of day as well as with different peak load timing. This was done to investigate the heat pump sizing recommendation “gap” using Manual J calculation and EnergyPlus™ methods. This work illustrates that sizing variable-capacity heat pump systems can be optimized to building loads with detailed data and should be combined with high-efficiency envelope improvements to minimize heating loads.

• Summary Report

Most advanced thermostats are designed for central heating, ventilation, and air-conditioning (HVAC) systems—similar technology to address point-source heating and cooling systems such as window air conditioners (window ACs) and minisplit heat pumps (MSHPs) is not as advanced or prevalent in the market. NREL researchers evaluated infrared-based, third-party, internet-connected thermostats for room ACs and MSHPs that allow for remote temperature control and scheduling through mobile apps. The result of the evaluation is a summary of the basic technology assessment actions taken in a laboratory setting. Successes, market and technology barriers, and future research needs were identified from the evaluation that could enable this technology to lead to increased energy savings and improved comfort for users.

• Summary Report 

Incorporating high-performance construction technologies into affordable homes can be challenging but first-cost savings from small-scale construction can pay for performance upgrades that reduce long-term costs. The FSEC Energy Research Center provided technical assistance to Manatee County Habitat for Humanity for development of a small, one-bed/one-bath housing design to help address housing availability and affordability constraints. This case study provides guidance for cost-effectively applying ZERH program measures to small, detached dwelling units and HVAC design for low-load conditions in a hot humid climate.

• Fact Sheet

Evaluating the thermal performance of building components with actual weather conditions allows for accurate modeling predictions of future design configurations. Frontier Energy performed a short-term field test and calibrated modeling of a standard manufactured home in California to understand the actual envelope performance and refine a field-testing methodology for this housing type. This case study informs the development of advanced manufactured homes that will improve design and construction practices.

• Summary Report

Air to water heat pumps (AWHPs) when coupled with thermal energy storage have the potential to be responsive to grid conditions. Frontier Energy evaluated AWHPs with and without thermal storage options using a calibrated above-code performance home, different time-of-use utility rate scenarios, and different climate zones. The assessment report details cost-effectiveness, energy performance, and potential impacts to comfort for informed design decisions with this emerging technology.

• Summary Report

Ground source heat pump (GSHP) and solar technologies can be effective in cold climates, although ground temperature at high latitudes, system interactions, and rural logistics can impact potential benefits. NREL researchers evaluated the effectiveness and economics of a GSHP system installed together with solar photovoltaic panels and a battery storage system in a local community building in Ruby, Alaska. The result of this analysis provides guidance on integrated heat pump and solar energy systems for building designers in extreme climates or rural locations.

• Summary Report

Implementing carbon reduction technologies and innovations in construction requires an understanding of how current building systems perform relative to building decarbonization goals. IBACOS prepared this report and fact sheet to serve as foundational documents for the residential construction industry to help homebuilders benchmark their current performance and better understand the largest sources of carbon emissions in their homes.

• Summary Report
• Fact Sheet

Interior air quality management in extreme cold weather climates is complicated by cold air infiltration. An active occupant that is intelligently maintaining the environment through a combination of source control, ventilation, filtration, and monitoring can improve internal air quality. In this fact sheet, NREL researchers provide reference information for pollutants, sources, health effects, mitigation strategies, and potential costs relevant to extreme cold climate residences.

• Fact Sheet

3D-printed concrete (3DPC) construction is an emerging technology that comes with the associated benefits of high thermal mass walls but is not yet supported by a formal approach for modeling appropriate mass, insulation, and thermal bridging parameters. In this presentation, NREL researchers evaluated the thermal properties, annual energy consumption, and peak energy demands of 3DPC, wood frame construction, and concrete masonry unit wall constructions in different IECC climate zones. The results of this analysis provide guidance for designers and energy modelers on predicting the thermal performance of 3DPC wall assemblies.

• Summary Presentation

Design and installation quality for mechanical ventilation systems impact performance and the ability to properly measure and commission airflows. Industry installation design guidance typically does not incorporate commissioning into the installed system design, which can cause system airflow to be inadequately measured, or not measured at all. FSEC Energy Research Center developed two BASC guides to provide direction on system design requirements and testing methods that allow for effective airflow measurement and commissioning.  

• BASC Guide
• BASC Guide

For residential basement foundations, many new construction builders meet the basement insulation code requirement by installing a pre-manufactured insulation “blanket”, which is made up of a large fiberglass batt with a laminated facer, on the interior side of foundation walls. This simple installation method has led to condensation where the blanket insulation meets the surface of the concrete, resulting in potential durability and indoor air quality problems. IBACOS has developed a BASC guide to present an improvement to typical basement blanket insulation installations that will result in improved thermal performance and moisture durability.

• BASC Guide

This case study by the University of Nebraska-Lincoln evaluated the air leakage rates of a set of modular multifamily dwelling units at factory, post-transportation, and installed conditions. Additionally, site-built multifamily dwelling units of the same construction type, located in the same area, and permitted under the same energy code were evaluated. The report details the methodology and analysis along with opportunities for process and design improvement.

• Summary Report

This project characterizes software tools and methods that are being used or could be used to model multizone HVAC systems to better understand their performance capabilities and constraints, as well as identify needed improvement capabilities. IBACOS evaluated several building physics modeling tools to predict room-level thermal loads, HVAC system operation, temperature and comfort predictions, and scalability. The results of this analysis will be used to identify capabilities, and opportunities for improving, the state of the art of multizone energy and air distribution modeling both at a micro-, house-scale, and at a macro-national scale.

• Summary Report

The FSEC Energy Research Center conducted research to evaluate the effectiveness of interventions to isolate an ill person recovering from a contagious disease in a dwelling from the rest of the occupants. A single-family manufactured home was utilized with various controls and operating conditions for the evaluation, which focused on interventions requiring minor cost and effort on the part of the occupants.

• Summary Report
• Fact Sheet

Most long-term care (LTC) facilities were not designed for airborne infection control and guidance for retrofitting existing LTC spaces for isolation is limited. The University of Nebraska-Lincoln evaluated the effect of ventilation rate, directional airflow (e.g., pressure relationships), and airflow barriers on bioaerosol concentration and movement within long-term care LTC facilities. Additionally, a comprehensive literature review, field data collection test plan, and an evaluation of commercially available mitigation technologies are available in the report.

• Summary Report
• Published Article

Even though adding a kitchen exhaust duct can make such a positive impact on indoor air quality and noise, the conversion is rarely done in existing homes, except as part of a major kitchen renovation. Newport Partners developed a guide for the BASC to address knowledge gaps in the residential construction industry when retrofitting kitchen exhaust ventilation. The guide provides 'how-to' information on dealing with common existing systems and best practice techniques for ensuring a retrofitted kitchen ventilation system is capable of maintaining adequate indoor air quality.

• BASC Guide

Multiple SMEs have provided guidance, content, and technical reviews for the BASC Disaster Resistance tool. The guides offer information on increasing resiliency, adaptability, and responsiveness in the face of environmental disaster through relevant 'how-to' guidance.

• BASC Disaster Resistance Tool

New construction in colder climates requires insulation for heated slabs. This energy-efficient measure has multiple benefits, but improper design or installation can diminish the results. Building Science Corporation developed detailed guidance and drawings for insulating monolithic slabs in response to common industry issues through a BASC guide. Slab foundation system best practices for designing to overcome thermal bridging, moisture, and air quality issues are discussed.

• BASC Guide

NREL expanded the impact of Home Improvement Expert checklists with Spanish versions of all 21 checklists that will allow quality and performance construction standards to be available for a greater audience.

• BASC Spanish Versions

Home energy management systems (HEMS) are part of a quickly expanding product market that provides homeowners with the ability to control energy consuming devices through programmed schedules, control logic based on occupancy sensors or weather data, machine learning, and utility signals. Stakeholders have identified the inability of current modeling algorithms to quantify the benefits of HEMS due to the broad range of product and occupant behavior combinations as a major barrier to utility program incentives and energy efficiency credits in energy codes. For this project, Frontier Energy evaluated the expected range of energy savings for a HEMS that minimally complies with the ENERGY STAR Smart Home Energy Management Systems.

• Summary Report

Bringing supply and return ductwork into conditioned space is a well-documented strategy for improving the energy efficiency of a home. Central returns can offer an efficient and effective strategy for bringing the return into conditioned space by eliminating the need for dedicated returns; however, the room return air pathway must be designed correctly, and any sensitivity considered. IBACOS evaluated modeled scenarios using different supply and return air distribution strategies to quantify airflow balance and comfort delivery to rooms in a home when the doors to the rooms are open and closed. The sensitivity of different supply and return topologies quantified are presented with possible solutions for trade contractors and builders.

• Summary Report
• Fact Sheet