HERS Blower Door & Duct Testing 3

Question 1

What is the purpose of the pressure pan test in duct diagnostics?

Accepted Answer

To locate which registers have the greatest duct leakage to outside

Answer

A pressure pan placed over each register measures the pressure difference behind it, identifying registers associated with ducts that leak outside the conditioned space.

Question 2

During a blower door test, which measurement channel on the manometer typically reads building pressure with respect to outside?

Accepted Answer

The differential channel (B-A or A-B)

Answer

The differential channel measures the pressure difference between inside and outside (or across the blower door fan), which is the key value for calculating air leakage.

Question 3

A rater finds that CFM25 out (duct leakage to outside) exceeds the RESNET threshold for the home size. What is the most appropriate next step?

Accepted Answer

Report the result and recommend duct sealing, then retest

Answer

When duct leakage exceeds thresholds, the rater reports the finding, recommends corrective duct sealing by the contractor, and then conducts a retest to verify compliance.

Question 4

What term describes duct leakage that exits into an unconditioned space such as an attic or crawlspace?

Accepted Answer

Duct leakage to outside

Answer

Duct leakage that goes into unconditioned spaces (attic, crawlspace, garage) is called duct leakage to outside because it effectively leaves the conditioned envelope.

Question 5

Which instrument is used to simultaneously measure fan flow and building pressure difference during a blower door test?

Accepted Answer

Digital manometer connected to the blower door fan and building

Answer

A digital manometer measures both the pressure difference across the building envelope and the flow through the blower door fan, allowing CFM50 to be calculated.

(HERS) Certified Home Energy Rating System Rater Practice Test

(HERS) Certified Home Energy Rating System Rater Practice Test

HERS Blower Door & Duct Testing 3