Which of the following is a moisture control strategy?

• A. Add insulation
• B. Increase humidity
• C. Use balanced mechanical ventilation (HRV or ERV)
• D. Install vinyl flooring

Answer: (C)

Moisture control comes from actively managing the humidity in indoor air. A balanced mechanical ventilation system, like an HRV or ERV, does this by exchanging indoor air with outdoor air at a controlled rate. Because it’s balanced, the amount of air being brought in equals the air being exhausted, which helps prevent pressure-driven leaks that could pull in moist outdoor air or push moist indoor air into walls and attic spaces. An HRV focuses on recovering heat, while an ERV also recovers some moisture, helping to keep indoor humidity at comfortable, safer levels year-round.

This reduces moisture buildup from activities like cooking, showering, and drying clothes, which lowers condensation on windows and surfaces and reduces mold risk, all while improving energy efficiency by reusing heat (and moisture, in the case of an ERV).

Other options don’t actively control moisture in the same way: adding insulation helps with energy and can reduce condensation on cold surfaces but doesn’t remove humid air; increasing humidity obviously raises moisture levels; vinyl flooring is a surface choice rather than a method to control indoor moisture.