Diagnostic and Field Testing Flashcards
7 cards from real HERS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Diagnostic and Field Testing flashcards as text
What is 'leakage to outside' in duct testing, and why is it more important than total leakage for energy performance?
Answer: Leakage from ducts located outside the conditioned space; it directly wastes conditioned air to unconditioned areas
Leakage to outside represents conditioned air lost to unconditioned spaces (attics, crawlspaces), which directly wastes energy by reducing system delivery efficiency.
During a duct pressurization test, a rater tapes all supply and return registers. What is the purpose of this step?
Answer: To isolate the duct system so only duct leakage is measured, not intentional airflow openings
Taping registers closes the intentional airflow openings so the pressure test only measures unintended leakage in the duct system, not air escaping through registers.
A HERS rater is testing a home with both a central forced-air system and a mini-split. How should the mini-split be treated in duct leakage testing?
Answer: Mini-splits have no ductwork and are not subject to duct leakage testing
Mini-split systems are ductless — they deliver conditioned air directly without ductwork, so they are exempt from duct leakage testing requirements.
What is the RESNET-defined threshold for 'tested duct leakage to outside' that qualifies as ENERGY STAR Homes v3.1 duct leakage compliance in most climate zones?
Answer: 4 CFM25 per 100 sq ft of conditioned floor area
ENERGY STAR Homes v3.1 requires total duct leakage to outside of ≤4 CFM25 per 100 sq ft of conditioned floor area for compliance in most climate zones.
A rater finds that a home's blower door test result is significantly better than expected based on visual inspection. What should the rater do first?
Answer: Check that all intentional openings (fireplace dampers, whole-house fans) are properly closed
An unexpectedly low leakage result often indicates an intentional opening was inadvertently sealed or closed; the rater must verify all openings are in their normal operating position.
In HERS field testing, what is the purpose of the 'pressure pan' test?
Answer: To identify which specific ceiling or wall cavities are connected to the duct system as leakage pathways
A pressure pan placed over a ceiling penetration or register opening while the house is depressurized identifies leaky duct connections by revealing pressure communication with cavities.
What field measurement is used to verify that an HVAC system has adequate refrigerant charge during a HERS site visit?
Answer: Temperature split (return air vs. supply air temperature difference) or subcooling/superheat measurements
Refrigerant charge verification uses temperature split (typically 14–22°F for cooling) or more precisely subcooling and superheat measurements to confirm proper refrigerant levels.