If you are not familiar with the Preservation Brief series, check out the National Park Service's website:
http://www.nps.gov/history/tps/how-to-preserve/briefs.htm
They have some great information for historic property owners. Brief #3 focuses on improving energy efficiency in historic buildings.
images:
The Sewing Room at Stonehurst Place
http://www.stonehurstplace.com/
Before and After. We added open-cell foam insulation to reduce air infiltration and create a tight building envelope.
