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Air Leakage Metrics

What this tool does

Blower door installed in house.
Contractors use a blower door to measure air leakage. Image courtesy of PNNL.

You can calculate up to eight air leakage metrics, including ACH50, equivalent leakage area (EqLA), effective leakage area (ELA), specific leakage area (SLA), and more. Determine if your building complies with the International Energy Conservation Code or Energy Star Qualified Homes requirements for ACH50 or the Washington State requirement for SLA. 

This unique RED Calc tool uses our “solve-all” technique, but in a different way than our other solve-all tools. Instead of selecting one of eight values to solve, you select one of eight values to enter; the other seven are solved by the tool.

You will find this tool very useful for determining airtightness code compliance and target tightness values, and for your education.

Calculated values

  • Leakage at 50Pa
  • ACH50
  • Equivalent leakage area (EqLA)
  • Effective leakage area (ELA)
  • Specific leakage area
  • Leakage at 50Pa / floor area
  • Leakage at 50Pa / surface area
  • Leakage coefficient

Tips

  • Clicking the label for any input or result will cause a popup help box to appear. This help box includes the allowed and normal values (for inputs).
  • In the bottom section of the tool, you must select one of the eight metrics with the radio buttons and enter its value. All seven other metrics will be calculated.
  • A few of the calculated results in the bottom section of the tool require that certain input values be entered in the top section of the tool. For example, “Leakage at 50Pa / floor area” and “Specific leakage area” require that “Floor area” in the top section of the tool be entered. Additionally, “Leakage at 50Pa / surface area” requires the “Surface area” in the top section of the tool to be entered.

Best Practices

IECC Climate zone map with table of International Energy Conservation Code tightness requirements.
International Energy Conservation Code tightness requirements. Source: Air Leakage Guide, September 2011, U.S. Department of Energy

Some of the metrics calculated by this tool are used by various codes and standards. For example, the International Energy Conservation Code requires the ACH50 values for the Code years and climates shown in the map and tables shown here.

Some other published requirements include the Canadian R-2000 Program of 1.5 ACH50 and the Passivhaus Standard of 0.6 ACH50. Also, see the table below for the Energy Star Qualified Homes requirements.

Disclaimer

This content is a work created with funding provided by the United States Department of Energy under Contract no DE-AC05-076RL01830 for the operation of Pacific Northwest National Laboratory. The information and guidance provided by Pacific Northwest National Laboratory (PNNL) in the content are intended solely for educational purposes only and do not constitute formal training or certification. It is provided with the explicit understanding that neither the United States Government nor the United States Department of Energy, nor the Contractor, nor any or their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Viewers assumes full responsibility for all actions that they may take from information provided in this content including ensuring the safety, code compliance, and proper functionality of any products they choose to install. Installation and use of such products should be performed in accordance with local regulations and manufacturer instructions.