Air Sealing

Modified on Mon, 19 Jan at 12:35 PM

Air Sealing Library Help

Infiltration Unit

The unit used to measure infiltration. For the infiltration value to be used in a confirmed HERS rating, a certified HERS rater must perform a Blower Door Test, mark it as tested in the Edit Design page and input the infiltration value in a unit other than ACH Natural. Otherwise, for the HERS rating, RESNET defaults will be used for the Rated Home.
Options include:

ACH Natural - Estimate of building air changes per hour during typical conditions. This cannot be measured and therefore will be overridden by RESNET defaults when the HERS Index is calculated.
ACH at 50 Pa - The number of complete building air replacements that occur per hour during a blower door test at 50 Pa. Use total conditioned volume, including conditioned basements, to convert from CFM50. Blower Door testing procedures can be found in Chapter 8 of the RESNET Standards.
CFM at 50 Pa - Measured airflow in cubic feet per minute during a blower door test at 50 Pa. Blower Door testing procedures can be found in Chapter 8 of the RESNET Standards.
Effective Leakage Area - Also known as ELA, the area (in²) of a theoretical hole with rounded edges in the building envelope that would leak as much as all of the building's holes at a pressure difference of 4 Pa. Note that ELA is different from Equivalent Leakage Area (EqLA) which is the area of a sharp-edged theoretical hole at 10 Pa.
Specific Leakage Area - calculated by dividing ELA by the conditioned floor area in like units (i.e. in²/in² or ft²/ft²).

Infiltration

The rate of infiltration, in the unit specified above.