HERS Diagnostic and Field Testing 2

Question 1

When performing a duct leakage test, which metric is used to express total duct leakage in RESNET standards?

Accepted Answer

CFM25 total

Answer

ACH50

Answer

CFM50 total

Answer

Pascal differential

Question 2

A HERS rater measures duct leakage to outside at 52 CFM25 on a 1,800 sq ft home. What is the duct leakage to outside as a percentage of conditioned floor area?

Accepted Answer

2.9%

Answer

3.5%

Answer

4.2%

Answer

5.1%

Question 3

During blower door testing, what does a high inside-out pressure differential (house more negative than outside) indicate?

Accepted Answer

The fan is depressurizing the house as expected

Answer

The house is well-sealed

Answer

Duct leakage is pulling air in

Answer

The manometer is reading incorrectly

Question 4

What is the purpose of a 'duct blaster' test conducted with the air handler fan OFF?

Accepted Answer

To isolate and measure duct system leakage independently from the air handler

Answer

To measure envelope leakage only

Answer

To test the HVAC system's airflow capacity

Answer

To identify window and door leaks

Question 5

Which condition would most likely cause an artificially LOW blower door reading during envelope testing?

Accepted Answer

An open window on the leeward side

Answer

High wind speeds outside

Answer

A large interior partition wall

Answer

Stack effect from temperature differences

Question 6

In a HERS duct leakage test, 'leakage to outside' differs from 'total leakage' because:

Accepted Answer

Leakage to outside only counts ducts outside conditioned space

Answer

Total leakage includes supply and return separately

Answer

Total leakage measures at a different pressure

Answer

Leakage to outside excludes filter bypass leakage

Question 7

A rater is testing a home with a sealed attic (unvented). When measuring duct leakage to outside, how should ducts located entirely within this sealed attic be treated?

Accepted Answer

They do NOT count as outside leakage since the attic is within the conditioned envelope

Answer

They count as outside leakage because attics are always outside

Answer

They must be tested separately with a secondary duct blaster

Answer

They are excluded from HERS calculations entirely