Asset Score includes an air infiltration rate among the components that characterize a building’s envelope, based on assumptions that are outlined in the Program Overview and Technical Protocol. Users may specify infiltration rates if the building has undergone whole-building pressurization testing. Or, users may specify the energy code with which the building complies to, and the infiltration rate will be calculated and inferred based on the code. For the IECC, the rate will be based on the building’s climate zone as well.
The infiltration inputs selected apply to the whole building, and do not need to be assigned to individual blocks.
Energy Asset Score Inputs for Infiltration:
Has the whole building air-leakage been tested? -- Radio buttons selections for Yes or No if the building has undergone whole-building pressurization testing in accordance with ASTM E779 or ASTM E1827.
Air leakage rate -- Selecting Yes if the building has undergone whole-building pressurization testing, will display an input box for this field. Enter the whole building air-leakage rate under the pressure differential of 0.3 inch w.c. (75 Pa). A maximum of 4.2 CFM/ft2, and a minimum of 0.02 CFM/ft2 may be entered. For comparison purposes, Standard 90.1-2004 uses an infiltration rate of 1.8 CFM/ft2, and the Passive House Standard has a value of 0.08 CFM/ft2.
Infiltration Compliance -- Selecting No if the building has not undergone whole-building pressurization testing, will display a drop-down menu of building energy codes and standards. Select the energy code the building complies with from the list below, and an infiltration rate associated with that code will be applied:
- ASHRAE 90.1-2004/2007
- ASHRAE 90.1-2010
- ASHRAE 90.1-2013
- ASHRAE 90.1-2016
- IECC 2006/2009
- IECC 2012
- IECC 2015
- IECC 2018
- Passive House Standard
If I don’t know is selected from the drop down list, a default infiltration rate of 1.8 CFM/ft2 will be used. This is the infiltration rate used in the prototype buildings for version ASHRAE Standard 90.1-2004.