Infiltration Help

• 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).
• 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.

1. No obstructions or local shielding.
2. Typical shelter for an isolated rural house.
3. Typical shelter caused by other buildings across the street.
4. Typical shelter for urban buildings on larger lots where sheltering obstacles are more than one building height away.
5. Typical shelter produced by buildings or other structures immediately adjacent (closer than one house height): e.g., neighboring houses on same side of street, trees bushes, etc.
   
   

• Blower-door tested: Select this if the entered infiltration information reflects actual blower door test results according to testing protocol in RESNET Standards Ch. 8. This allows a confirmed HERS report to be printed, and the entered infiltration information will be used for the rated home when performing HERS calculations.
• To be blower-door tested: Select this if the building will be blower door tested before applying for permits. This restricts you to only printing projected HERS reports, but allows you to see the impact of infiltration characteristics other than those generated for the HERS reference home.
• Untested: Select this if the building will not be blower door tested. This allows a confirmed HERS report to be printed, but when performing HERS calculations the HERS reference home’s infiltration will be used for the rated home.
• Threshold / Sampled: Choose this for both Threshold and Sampled ratings.

In accordance with RESNET/ANSI/ICC 380 (effective July 1, 2018), if a single point test has been completed, the resulting number must be multiplied by 1.1 before entering the value into Ekotrope.  Ekotrope will not make any modifications to the entered value, it will use it as-is for modeling.  Multi-point tests may be entered unmodified.

In Version 4.0.0 and later, only a compartmentalization test shall be used and no multiplier shall be applied. Ekotrope automatically adjusts the infiltration rate for the HERS and ERI rated homes as prescribed in RESNET/ANSI/ICC 301.

If the project you are modeling is in a version prior to 4.0:

In accordance with RESNET Guidelines for Multifamily Ratings (published in 2014), if an unguarded blower door test is performed on an attached dwelling unit that is not built on a slab and does not use corridor as ventilation supply air, then the blower door test result shall be multiplied by 0.85 before entering it into Ekotrope.

A guarded blower door test is performed with all interior adjacent spaces at the same pressure as the dwelling unit being tested.  By doing this it effectively measures the leakage to outside for the unit.  An unguarded (aka compartmentalization)  test means only the tested dwelling unit is pressurized, so it measures the total leakage of the unit.  Results from a compartmentalization test do not reflect where the leakage is coming from.