What this tool does
The ASHRAE 62.2-2019 RED Calc tool handles all the requirements of the Standard, including new and existing buildings, the alternative compliance path, and infiltration credit. We have added useful features, including the advanced blower door inputs option, the fan-run time option for intermittent operation of dwelling-unit ventilation, and the dwelling-unit leakage rate solver.
This tool complies with all of the requirements of the ASHRAE 62.2-2019 Standard, so you can use it with confidence.
- Effective annual average infiltration rate.
- Dwelling-unit Total required ventilation rate, Qtot.
- Filtration credit, if air handler qualifies for this credit.
- Alternative compliance supplement.
- Infiltration credit, Qinf.
- Dwelling-Unit Required mechanical ventilation rate, Qfan.
- Calculations for both balanced and unbalanced (exhaust or supply) ventilation.
- Fan run-time per hour.
- Corresponding measured leakage @ 50Pa for a chosen dwelling-unit ventilation rate.
- 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).
- The 2016 version of the ASHRAE 62.2 Standard is the first to include dwelling units in multifamily buildings of any height. However, ASHRAE 62.2-2016 did not address common areas in multifamily buildings, such as hallways, lobbies, meeting areas, etc. These areas continue to be regulated by the ASHRAE 62.1 Standard.
- Weather data is included for the United States and Canada. The weather data for the 2019 tool includes 1100 locations in North America.
- 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 buildings, based on the requirements of the 62.2-2019 Standard.
- For new and existing, horizontally-attached single-family dwellings, an infiltration credit is available based on the ratio of the exterior envelope surface area to total envelope surface area. When you select the appropriate drop-down items in the RED tool and enter the corresponding values, this infiltration credit, based on a blower door test, is calculated for you.
- For multifamily dwellings, refer to the “Multifamily Dwellings” section below.
- The Dwelling-Unit Ventilation Run-Time Solver allows you to determine run-time per hour if you wish to operate the dwelling-unit fan intermittently.
- The Dwelling-Unit Leakage Rate Solver allows you to determine the measured leakage rate at 50 pascals that corresponds to a chosen dwelling-unit mechanical ventilation rate.
- The ASHRAE 62.2 Standard is written as a minimum standard; you may exceed the minimum requirements of the Standard.
Although the first version of the ASHRAE Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings, was published in 2003; the 2010 version was the first to gain national attention.
The Wisconsin low-income weatherization program was the first organization to adopt the residential ventilation/IAQ standard, in late 2004. The adoption of the ventilation/IAQ standard gained momentum in 2011 when the Department of Energy required the use of ASHRAE 62.2-2010 in the low-income weatherization program by the end of the 2012 program year. In 2013 the Building Performance Institute (BPI) adopted the 2013 version of the standard.
The 2016 version of the 62.2 Standard included a significant change in scope: Rather than addressing single-family and multifamily buildings of three stories and less above grade (low-rise), as the previous versions did, it addresses dwellings in buildings of any height, including high-rise multifamily buildings. The 2019 version has the same scope as the 2016 version.
- 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 dwelling 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 dwelling-unit 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 dwelling-unit ventilation fan airflow rate with a variable-speed control to satisfy the actual dwelling-unit airflow rate, Qfan. Or, if you are using intermittent operation of the dwelling-unit ventilation fan, adjust the run time of the fan to correspond with the “Required mechanical ventilation rate, Qfan.
- Regarding the infiltration credit and the required blower door testing, ASHRAE 62.2-2019 Standard states: “Effective Annual Average Infiltration Rate” 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.” (ASHRAE 62.2-2019, Section 4.1.2). Additionally, single-point blower door testing is allowed by the 2019 version of the standard.
- The ASHRAE 62.2-2019 Standard allows the use of the alternative compliance path (Appendix A of the Standard) for existing dwellings. This path allows compensation for deficits in local ventilation (kitchens and bathrooms) by increasing the flow rate of dwelling-unit 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 dwelling-unit ventilation fans.
The 2019 version of the ASHRAE 62.2 Standard includes dwellings in multifamily buildings of any height, including more than three stories above grade. Previous versions only included dwellings in multifamily buildings of three stories or fewer above grade. In order to use the RED Calc Free 62.2-2019 tool for dwelling units in multifamily buildings, select “Attached to other dwelling unit(s)” in the “Dwelling unit is” drop-down.
Note: The only infiltration credit allowed for dwellings in multifamily buildings by the 2019 version of the 62.2 Standard is for horizontally-attached single-family units, such as side-by-side duplexes, triplexes, and row houses. Dwellings units that are attached to other dwelling units in any way other than via side walls are not allowed as infiltration credits.