retrofit insulation

Insulation contractor retrofitting exterior house wall cavity with blown-in insulation

Blown-In Cellulose Wall Insulation vs. Interior Foam Retrofit: Costs, R-Values, and Payback for US Homes

August 17, 202616 min read

Compare blown-in cellulose and injected expanding foam retrofits for uninsulated wall cavities in older US homes. Analyze upfront installation costs, thermal R-values, moisture vapor permeability, settling risks, and real-world energy payback across climate zones.