We just got rid of our ineffective, old attic insulation and installed closed cell blown-in foam in the attic rafters. The difference so far is remarkable. Attic temps on sunny days are at least 20 to 30+ degrees cooler which has enabled us to forego using air conditioning on multiple days.The extra cost of closed cell foam is significant over fiberglass, however the higher R value and ability to seal in the attic space made it worthwhile in my opinion.
The work was done by Green Stamp of Waltham. They coordinated the insulating with our general contractor, North River Builders of Concord. Quite pleased with both companies.
Can’t wait to see the reported additional benefit of ice dam prevention in the winter.