InterNACHI Insulation and Ventilation 5

Question 1

Under ASHRAE 62.2, what is the minimum recommended whole-building mechanical ventilation rate for a 2,000 square foot home with 3 bedrooms?

Accepted Answer

45 CFM

Answer

ASHRAE 62.2 uses a formula based on floor area and number of bedrooms; for a typical 3-bedroom, 2,000 sq ft home the result is approximately 45 CFM of continuous ventilation.

Question 2

What deficiency does an inspector report when vermiculite insulation is found in an attic of a home built before 1990?

Accepted Answer

Vermiculite from that era is likely to contain asbestos and is a potential health hazard

Answer

Most vermiculite sold before 1990 came from the Libby, Montana mine and was contaminated with asbestos; its presence should trigger an asbestos testing recommendation.

Question 3

What is the purpose of an 'energy recovery ventilator' (ERV) compared to a standard heat recovery ventilator (HRV)?

Accepted Answer

ERVs recover both heat and moisture from exhaust air; HRVs recover heat only

Answer

An ERV transfers both sensible heat and moisture (latent energy) between incoming and outgoing air streams, while an HRV transfers only sensible heat.

Question 4

A home inspector finds kraft-faced fiberglass batts installed with the facing toward the exterior (cold side) in a Climate Zone 6 wall. What is the concern?

Accepted Answer

Facing toward the cold side places the vapor retarder on the wrong side, trapping moisture in the cavity

Answer

In cold climates, the vapor retarder should be on the warm (interior) side; placing it on the cold side traps moisture driven from the interior inside the wall cavity.

Question 5

What condition is indicated when an inspector observes dark staining on attic insulation directly below roof sheathing nail tips?

Accepted Answer

Condensation is forming on cold nail tips and dripping onto insulation — a sign of inadequate attic ventilation

Answer

In cold weather, nail tips protruding through sheathing become cold spots where moisture condenses; the drips stain insulation below and indicate inadequate attic ventilation or air sealing.

(InterNACHI) International Association of Certified Home Inspectors Practice Test

(InterNACHI) International Association of Certified Home Inspectors Practice Test

InterNACHI Insulation and Ventilation 5