#728: Too Much Stuff, ERV Ductwork, and Spray Foam Under Paneling

Prioritize proper sealing and insulation of microwave exhaust vents, especially in cold climates, to prevent frost and thermal bypasses.

When installing ERV/HRV systems, perform accurate CFM calculations based on ASHRAE 62.2 or IRC guidelines to ensure adequate ventilation for the home's size and occupancy.

Consider professional ductwork design for ERV/HRV systems to optimize airflow, minimize static pressure, and ensure effective air distribution, especially with complex layouts.

Implement thorough commissioning for ERV/HRV systems, including measuring and balancing incoming and outgoing airflow, to prevent depressurization or pressurization of the house.

For exterior vent penetrations, utilize specialized gaskets and ensure proper flashing to create reliable airtight and watertight seals, especially for ERV/HRV intake and exhaust points.

Avoid relying solely on closed-cell spray foam as an air or vapor barrier directly behind interior wood paneling; consider additional layers like drywall for cheap insurance against future moisture issues.

Be aware that 2 inches of closed-cell spray foam may not be a sufficient vapor retarder in very cold climates (zone 7 and 8) with high indoor humidity, potentially requiring 3 inches or more.