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ASHRAE 62.2-2010 CA Tool Guide

What this tool does – [Tool]

Kitchen range hood

The ASHRAE 62.2 California tool handles all the requirements of the unique version of the 62.2 Standard, including new and existing buildings, single-family and multifamily buildings, the alternative compliance path, and infiltration credit. We have added useful features, including the advanced blower door inputs option and the fan-run time option for intermittent operation of whole-building ventilation.

It is very important that this tool is used ONLY in California. This RED Calc Free tool is based on the California version of the ASHRAE 62.2-2010 Standard that was prepared with ASHRAE’s permission by the California Energy Commission for the most recent update of the California Building Energy Efficiency Standards (California Code of Regulations, Title 24, Part 6).

Calculated values

  • Effective annual avg. infiltration rate.
  • Whole-building Total required ventilation rate.
  • Alternative compliance supplement.
  • Infiltration credit.
  • Whole-building Required mechanical ventilation rate, Qfan.
  • Fan run-time per hour.


  • 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).
  • For some tighter buildings, the required mechanical ventilation rate is lower if the infiltration credit is NOT used.
  • Weather data is included for 73 weather station locations in California. The “Closest weather station” section of the tool is displayed only when you are using the infiltration credit feature.
  • As an aid in finding the closest weather station location, use the Weather Station Data RED Calc Free tool. Select the “Show map” checkbox to select the closest weather station on the Google map.
  • You may choose to use the Advanced Blower Door Inputs to adjust your results for temperature, altitude, and pressure exponent.
  • You may choose to use the Local Ventilation Alternative Compliance feature for existing dwellings. This feature includes one kitchen and from one to five bathrooms. This option may not be used for new dwellings.
  • The Whole-Building Ventilation Run-Time tool allows you to determine run-time per hour if you wish to operate the whole-building fan intermittently.
  • The ASHRAE 62.2 Standard is written as a minimum standard; you may exceed the minimum requirements of the Standard.


The following paragraphs are excerpted from the cover of the California version of the ASHRAE 62.2-2010 Standard.

This is a non-ASHRAE-prepared version of ANSI/ASHRAE Standard 62.2-2010, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings. This document was prepared with ASHRAE’s permission by the California Energy Commission staff for the 2013 update to the California Building Energy Efficiency Standards (California Code of Regulations, Title 24, Part 6). It includes ANSI/ASHRAE Addenda to ANSI/ASHRAE Standard 62.2-2007 listed in Appendix B and ANSI/ASHRAE Addenda b, c, e, g, h, i, j, l, and n to ANSI/ASHRAE Standard 62.2-2010, as well as the errata to Standard 62.2-2010 noted in the list dated 7/21/10. It has not been through the consensus process of the American National Standards Institute and is therefore not an ANSI-approved document.

This document is not the current version of ASHRAE Standard 62.2-2010 [or 62.2-2013]. This document was the current version of ASHRAE Standard 62.2-2010 at the time the California Energy Commission adopted it for the 2013 update to the California Building Energy Efficiency Standards.

Best Practices

  • In order to use the infiltration credit for a new dwelling, you must conduct a blower door test. The appropriate sequence to use for a new building is as follows: First, you must estimate what you think the blower door test value will be when the dwelling is completed. Second, install a whole-building fan with a capacity that exceeds your estimate for the final airflow rate. Third, conduct the blower door test when the dwelling is finished. Finally, adjust the whole-building ventilation fan airflow rate with a variable-speed control to satisfy the final whole-building airflow rate, Qfan.
  • Regarding the infiltration credit and the required blower door testing, the ASHRAE 62.2-2010 California Standard states: “Effective Annual Average Infiltration Rate (Qinf) shall be calculated using the normalized leakage calculated from measurements of envelope leakage using either ASTM E779 or CGSB 149.10. The authority having jurisdiction may approve other means of calculating effective leakage area (ELA), such as the RESNET Mortgage Industry National Home Energy Systems Standard.“. Both ASTM E779 and CGSB 149.10 require multi-point blower door tests.

    The above statement from ASHRAE 62.2-2010 California requires a multi-point blower door test for compliance with the Standard, “unless the authority having jurisdiction [approves] another means of calculating effective leakage area (ELA). . .” In other words, when using the infiltration credit, you are not in compliance with the Standard unless you do a multi-point blower door test, unless your “authority having jurisdiction” allows you to use a single-point test. So, keep in mind that a single-point test is not best practice, and, unless you have approval, it is not in compliance with the Standard.

  • The ASHRAE 62.2-2010 California Standard allows the use of the alternative compliance path (Appendix A of the Standard) for existing dwellings. This path allows adjustment for deficits in local ventilation (kitchens and bathrooms) by increasing the flow rate of whole-building ventilation. Generally, the use of this alternative path saves installation time and money, but it might result in lower indoor air quality. Whenever possible, avoid the use of the alternative compliance path and install separate local and whole-building ventilation fans.

Multifamily Dwellings

The 2010 California version of the ASHRAE 62.2 Standard includes a significant section for multifamily buildings (the Standard addresses multifamily buildings of three stories or fewer above grade). In order to use the RED Calc Free 62.2 California tool for multifamily dwelling units, select “Multifamily” as your choice for Building type in the top section of the tool.


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