HERS Duct Leakage Testing 2

Question 1

What does the term 'duct leakage to outside' (Qto) specifically measure?

Accepted Answer

Air leaking between the duct system and unconditioned space

Answer

Duct leakage to outside (Qto) measures air exchanged between the duct system and unconditioned spaces such as attics, crawlspaces, or garages.

Question 2

During a duct leakage test, all registers are sealed with tape and plugs. What is the purpose of this step?

Accepted Answer

To isolate the duct system so only duct envelope leakage is measured

Answer

Sealing registers isolates the duct system from the living space so that the Duct Blaster measures only leakage through duct seams and connections.

Question 3

A home has a Duct Leakage to Outside of 8% of floor area. Under ENERGY STAR v3.2, what is the maximum allowable Qto as a percentage of conditioned floor area?

Accepted Answer

4%

Answer

ENERGY STAR v3.2 requires duct leakage to outside to be no more than 4 CFM25 per 100 sq ft of conditioned floor area.

Question 4

What unit is most commonly used to express duct leakage test results in the U.S.?

Accepted Answer

CFM at 25 Pascals (CFM25)

Answer

Duct leakage in the U.S. is standardized at CFM25, meaning cubic feet per minute of airflow at 25 Pascals of induced pressure.

Question 5

Which of the following conditions would MOST likely cause a duct leakage test to underestimate actual leakage?

Accepted Answer

Registers that were not fully sealed before testing

Answer

Incompletely sealed registers allow conditioned air to pass through, bypassing the Duct Blaster and causing the measured leakage to be lower than actual.

(HERS) Home Energy Rater Certification Practice Test

(HERS) Home Energy Rater Certification Practice Test

HERS Duct Leakage Testing 2