HERS Diagnostic and Field Testing Questions and Answers

Question 1

A HERS Rater performs a blower door test on a new construction home and obtains a result of 6.5 ACH50. The applicable energy code for the jurisdiction requires a maximum of 5.0 ACH50. While the blower door is still running, which of the following is the most effective and direct method for the rater to identify the largest air leakage pathways?

Accepted Answer

Systematically feeling for drafts by hand at common leakage points like sill plates and window frames.

Answer

While an infrared camera and zonal pressure diagnostics are valuable tools, the most direct and often most effective initial step is to use your senses. With the house depressurized to -50 Pascals, significant leaks are often obvious and can be felt by hand or seen with a smoke puffer at common problem areas such as sill plates, band joists, window/door trim, and penetrations for wiring and plumbing. This allows for quick identification and subsequent sealing.

Question 2

During a duct leakage test on a system located entirely within the conditioned space, a rater can perform either a 'total duct leakage' test or a 'leakage to outside' test. According to RESNET standards, which test result can be used for compliance if the goal is to meet a 'leakage to outside' requirement?

Accepted Answer

The 'total duct leakage' test result can be used, as it will always be greater than or equal to the leakage to the outside.

Answer

According to RESNET Standard ANSI/RESNET/ICC 380, the total duct leakage test measures all leaks in the system, both to the inside and outside of the conditioned space. The 'leakage to outside' test is more complex, requiring a blower door to pressurize the house simultaneously. Because total duct leakage will always be a higher (or equal) value than leakage to the outside, its result can be conservatively used to demonstrate compliance with a leakage-to-outside standard.

Question 3

A rater is preparing to conduct a worst-case depressurization test in a Combustion Appliance Zone (CAZ) containing a natural draft water heater and a furnace. Which of the following is a critical first step in the standard procedure?

Accepted Answer

Establish and record the baseline pressure of the CAZ with reference to the outdoors before turning on any fans or appliances.

Answer

Before inducing depressurization by turning on exhaust fans and air handlers, it is essential to measure the baseline pressure difference between the CAZ and the outdoors. This baseline reading is the starting point from which the 'worst-case' depressurization level is calculated after all air-moving equipment is activated. Without this baseline, the net effect of the exhaust appliances cannot be accurately determined.

Question 4

A HERS Rater is using an infrared camera to inspect a wall cavity on a cold day. The camera shows a distinct, cool, feathery pattern on the interior drywall surface. This pattern most likely indicates:

Accepted Answer

A void or gap in the insulation allowing for air leakage and convection.

Answer

Cool, irregular, or feathery patterns seen with an infrared camera on a building surface typically indicate air leakage. The moving air cools the surface in a distinct pattern as it passes through gaps in the insulation or air barrier. In contrast, framing members (thermal bridges) usually appear as uniform, cooler vertical or horizontal lines, and moisture often has a more amorphous, splotchy appearance.

Question 5

When performing a zonal pressure diagnostic test with a blower door running, a rater measures the pressure difference between an attached garage and the main house. The reading is -45 Pa (Pascals). What does this reading indicate?

Accepted Answer

The air barrier between the house and the garage is very effective (tight).

Answer

During a blower door test where the house is depressurized to -50 Pa relative to the outdoors, any zone that is well-connected to the outdoors and well-sealed from the house will approach -50 Pa. A reading of -45 Pa indicates a very small pressure difference between the garage and the outdoors, meaning the primary air barrier between the house and the garage is intact and performing well. A low reading (e.g., -5 Pa) would indicate a leaky barrier.

(HERS) Certified Home Energy Rating System Rater Practice Test

(HERS) Certified Home Energy Rating System Rater Practice Test

HERS Diagnostic and Field Testing Questions and Answers