Questions about energy audit recommendations

A Baltimore homeowner asked a builder forum about conflicting advice from an energy audit. His 1941 brick colonial tested at 3,500 CFM50 (a measure of how much air leaks through the house per minute under test pressure), and the auditor's plan aimed to cut that to 2,250. The auditor's proposal: strip out the existing cellulose insulation in the attic, spray 8 inches of open-cell foam directly under the roofline (about R-29, below the R-49 usually recommended for this climate zone), and seal an attic hatch, turning the attic into conditioned, usable storage space. Cost after rebates would run about $7,600. The homeowner questioned using open-cell foam instead of closed-cell, since open-cell lets water pass through if the roof (now 24 years old) ever leaks. The contractor offered thicker open-cell or an upgrade to closed-cell foam for more money, but stuck to the plan of converting the attic into conditioned space rather than simply air-sealing the attic floor and topping it with more cellulose.

Two experts responding on the forum agreed with the homeowner's instincts. They said the "open-cell lets leaks show" argument is a weak reason to choose it over closed-cell foam, since price is really the only advantage. They also backed the homeowner's simpler alternative: seal the attic floor's leak points, keep the attic vented rather than conditioned, and add cellulose to reach at least R-49. Conditioning the roofline instead of the floor expands the size of the space that needs heating and cooling, which typically means more heat loss overall, especially with insulation levels below R-49.