HERS Blower Door & Duct Testing 2

Question 1

During a blower door test, what effect does a large open fireplace damper have on the result?

Accepted Answer

It increases the measured CFM50, making the house appear leakier

Answer

An open fireplace damper is a large pathway to outside and will increase the measured infiltration (CFM50), inflating the apparent leakage of the building shell.

Question 2

What is the primary reason HERS raters must depressurize ducts to a specific pressure (typically 25 Pa) during a duct leakage test?

Accepted Answer

To standardize results so tests from different homes and raters are comparable

Answer

Standardizing at 25 Pa ensures that duct leakage measurements are consistent and comparable across different test conditions, homes, and raters.

Question 3

In a duct leakage test, CFM25 total is measured at 300 cfm and CFM25 out is measured at 180 cfm. What is the duct leakage to outside?

Accepted Answer

120 cfm

Answer

Duct leakage to outside equals total leakage minus leakage to conditioned space: 300 − 180 = 120 cfm.

Question 4

Which condition must be established before starting a blower door test according to RESNET standards?

Accepted Answer

All interior doors must be open

Answer

RESNET requires all interior doors to be open so that the entire conditioned envelope is pressurized or depressurized uniformly during testing.

Question 5

What does a high ELA (Effective Leakage Area) value indicate about a home?

Accepted Answer

The home has a large equivalent hole size and poor air sealing

Answer

A high ELA means the combined leakage pathways are equivalent to a large hole, indicating poor envelope air tightness.

(HERS) Certified Home Energy Rating System Rater Practice Test

(HERS) Certified Home Energy Rating System Rater Practice Test

HERS Blower Door & Duct Testing 2