HERS Building Envelope & Insulation 2

Question 1

Which insulation material has the highest R-value per inch?

Accepted Answer

Closed-cell spray foam

Answer

Closed-cell spray foam provides approximately R-6 to R-7 per inch, the highest among common insulation materials.

Question 2

In RESNET standards, what is the primary purpose of a blower door test for the building envelope?

Accepted Answer

Quantify air leakage through the building shell

Answer

A blower door test depressurizes the home to measure air leakage (ACH50 or CFM50) through the building shell.

Question 3

What does ACH50 measure in residential energy testing?

Accepted Answer

Air changes per hour at 50 Pascals pressure difference

Answer

ACH50 is the number of air changes per hour measured when the home is pressurized or depressurized to 50 Pascals.

Question 4

When insulating a cathedral ceiling without a vented air space, which approach is code-compliant?

Accepted Answer

Unvented assembly using air-impermeable insulation meeting IRC requirements

Answer

Unvented cathedral ceilings require air-impermeable insulation (such as spray foam) meeting minimum R-value requirements per IRC Table R806.5.

Question 5

What is thermal bridging in a wall assembly?

Accepted Answer

Heat transfer through a conductive element bypassing insulation

Answer

Thermal bridging occurs when a conductive material (like wood studs or steel framing) creates a path for heat to bypass the insulation layer.

(HERS) Home Energy Rater Certification Practice Test