NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet)

One of 9 reports in the series: Building America Technical Highlight Fact Sheets available on this site.
Thumbnail image of item number 1 in: 'NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet)'.
Thumbnail image of item number 2 in: 'NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet)'.

PDF Version Also Available for Download.

Description

This technical highlight describes NREL research to develop models of uninsulated wall assemblies that help to improve the accuracy of building energy simulation tools when modeling potential energy savings in older homes. Researchers at the National Renewable Energy Laboratory (NREL) have developed models for evaluating the thermal performance of walls in existing homes that will improve the accuracy of building energy simulation tools when predicting potential energy savings of existing homes. Uninsulated walls are typical in older homes where the wall cavities were not insulated during construction or where the insulating material has settled. Accurate calculation of heat transfer through … continued below

Physical Description

2 p.

Creation Information

Creator: Unknown. January 1, 2012.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by the UNT Libraries Government Documents Department to the UNT Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 121 times. More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Creator

  • We've been unable to identify the creator(s) of this report.

Sponsor

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

About | Browse this Partner

Contact Us

Corrections Questions

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Titles

Description

This technical highlight describes NREL research to develop models of uninsulated wall assemblies that help to improve the accuracy of building energy simulation tools when modeling potential energy savings in older homes. Researchers at the National Renewable Energy Laboratory (NREL) have developed models for evaluating the thermal performance of walls in existing homes that will improve the accuracy of building energy simulation tools when predicting potential energy savings of existing homes. Uninsulated walls are typical in older homes where the wall cavities were not insulated during construction or where the insulating material has settled. Accurate calculation of heat transfer through building enclosures will help determine the benefit of energy efficiency upgrades in order to reduce energy consumption in older American homes. NREL performed detailed computational fluid dynamics (CFD) analysis to quantify the energy loss/gain through the walls and to visualize different airflow regimes within the uninsulated cavities. The effects of ambient outdoor temperature, radiative properties of building materials, and insulation level were investigated. The study showed that multi-dimensional airflows occur in walls with uninsulated cavities and that the thermal resistance is a function of the outdoor temperature - an effect not accounted for in existing building energy simulation tools. The study quantified the difference between CFD prediction and the approach currently used in building energy simulation tools over a wide range of conditions. For example, researchers found that CFD predicted lower heating loads and slightly higher cooling loads. Implementation of CFD results into building energy simulation tools such as DOE2 and EnergyPlus will likely reduce the predicted heating load of homes. Researchers also determined that a small air gap in a partially insulated cavity can lead to a significant reduction in thermal resistance. For instance, a 4-in. tall air gap (Figure 1a) led to a 15% reduction in resistance. Similarly, a 2-ft tall air gap (Figure 1c) led to 54% reduction in thermal resistance. NREL researchers plan to extend this study to include additional wall configurations, and also to evaluate the performance of attic spaces with different insulation levels. NREL's objective is to address each potential issue that leads to inaccuracies in building energy simulation tools to improve the predictions.

Physical Description

2 p.

Notes

Building America: Technical Highlight, Building Technologies Program (BTP)

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

About | Browse this Collection

What responsibilities do I have when using this report?

Digital Files

When

Dates and time periods associated with this report.

Creation Date

  • January 1, 2012

Added to The UNT Digital Library

  • May 19, 2016, 3:16 p.m.

Description Last Updated

  • July 31, 2025, 5:42 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 121
More Statistics

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

Thumbnail image of item number 1 in: 'NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet)'.
Thumbnail image of item number 2 in: 'NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet)'.

PDF Version Also Available for Download.

Citations, Rights, Re-Use

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Links for Robots

Helpful links in machine-readable formats.

Archival Resource Key (ARK)

International Image Interoperability Framework (IIIF)

Metadata Formats

Images

URLs

Stats

NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet), report, January 1, 2012; Golden, Colorado. (https://digital.library.unt.edu/ark:/67531/metadc837896/: accessed June 13, 2026), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.

Back to Top of Screen