A. Project Goals The goals of this research are: 1. To determine the energy efficiency of commercially-available reversible and irreversible insulation in a variety of historic wall assemblies. 2. To develop technical guidance for homeowners and cultural resource managers for improving energy efficiency of historic buildings without altering the historic features of the structure. B. Project Objectives The project will 1. Determine the energy performance of different types of insulation in historic buildings; 2. Understand the benefits and hazards of specific insulation materials and methods on historic buildings; 3. publish a publically accessible science-based best practice protocol for uses of insulation in historic structures; and 4. disseminate the results of the research through peer-reviewed journals, conference presentations, and educational webinars.