HERS Duct Leakage Testing 3

Question 1

When performing a rough-in duct leakage test before drywall, what component is typically not yet installed and must be accounted for?

Accepted Answer

The air handler or furnace

Answer

At rough-in stage, the air handler is often not installed, so the test port must be used to cap that opening and simulate the sealed system.

Question 2

Which RESNET standard governs the procedure for measuring duct leakage in residential buildings?

Accepted Answer

RESNET/ICC 380

Answer

RESNET/ICC 380 is the standard that specifies test methods for measuring building airtightness and duct leakage used by HERS raters.

Question 3

A duct system located entirely within the conditioned envelope (e.g., inside conditioned basement) would have what expected Qto value?

Accepted Answer

Approximately zero, since all leakage stays within conditioned space

Answer

When all ducts are inside the conditioned envelope, any leakage stays within conditioned space, so leakage to outside (Qto) is effectively zero.

Question 4

What is the primary purpose of normalizing duct leakage results to conditioned floor area?

Accepted Answer

To allow fair comparison of leakage across homes of different sizes

Answer

Normalizing to floor area (CFM25/100 sq ft) creates a size-independent metric so duct tightness can be compared consistently across houses of varying sizes.

Question 5

During a post-construction duct leakage test, the rater finds leakage at 12 CFM25/100 sq ft but the project requires 6 CFM25/100 sq ft. What is the BEST next step?

Accepted Answer

Locate and seal leakage points then retest

Answer

When results exceed the threshold, the rater must identify and seal leaky duct connections, then conduct a retest to verify compliance.

(HERS) Home Energy Rater Certification Practice Test

(HERS) Home Energy Rater Certification Practice Test

HERS Duct Leakage Testing 3