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About the Database

Here you will find more information about the purpose, audience, and uses for the National Residential Efficiency Measures Database.


NREL developed this database on behalf of the U.S. Department of Energy. The purpose of this project is to provide a national unified database of residential building retrofit measures and associated costs. These data are accessible to software programs that evaluate most cost-effective retrofit measures to improve the energy efficiency of residential buildings.

This publicly accessible, centralized database of retrofit measures offers the following benefits:

  • Provides information in a standardized format
  • Improves the technical consistency and accuracy of the results of software programs
  • Enables experts and stakeholders to view the retrofit information and provide comments to improve data quality
  • Supports building science R&D
  • Enhances transparency.


Software developers who require residential retrofit performance and cost data for applications that evaluate residential efficiency measures are the primary audience for this database. In addition, home performance contractors and manufacturers of residential materials and equipment may find this information useful.

Data Overview

Following is an overview of the database structure and content.

Measure Types

The database offers the following types of retrofit measures:

  • Appliances
  • Domestic Hot Water
  • Enclosure
  • Heating, Ventilating, and Air Conditioning (HVAC)
  • Lighting
  • Miscellaneous


A measure consists of a typical 'before-component' and 'after-component' state for a certain type of retrofit activity. Each measure will have components, costs, and possibly references associated with it.


A component provides the physical description of a particular building or system element including, but not limited to, any properties that affect the energy use of the home. A measure has a minimum of two components, before and after, but could have more than two.


Each component has a variety of properties to describe it in detail. The properties can include things about the component like lifetime, physical description, performance data, etc.

Cost Data

This database provides full cost estimates for many different retrofit measures. For each measure, the database provides a range of costs, as the cost data for a measure can vary widely across regions, houses, and contractors. Climate, construction, home features, local economy, and geographic location all affect the actual cost to perform any of these measures.

Some measures have multiple costs that must be added together to obtain total cost for the measure. For example, air conditioner measures have a fixed cost ($) and a normalized cost ($/kBtuh) that must be combined to get the total cost for the measure.

The cost data represents the total cost to implement the retrofit measure. For example, a new air conditioning unit that just meets code may cost $5,000. In addition to a measure that just meets code, the database may also include a measure to install a more energy-efficient air conditioner that costs $5,700. In this case, the cost listed in the database represents the full cost of the air conditioner ($5,700), and not the incremental cost ($700) to improve the unit from code.

This database is not intended to provide specific cost estimates for a specific project. The cost estimates do not include any rebates or tax incentives that may be available for the measures. Rather, it is meant to help determine which measures may be more cost-effective. NREL makes every effort to ensure accuracy of the data; however, NREL does not assume any legal liability or responsibility for the accuracy or completeness of the information.

Additional Information

To ensure overall building quality, comfort, safety, and durability when installing the efficiency measures found in this database, visit the Building America Solution Center. For guidance on how best to evaluate the energy the impacts of installing efficiency measures using whole-house energy analysis, see Building America House Simulation Protocols.

Version: v3.1.0