We are trying to become more energy efficient in our 1836 Colonial home. We are located in a Historic District and have to have any exterior renovation approved by our local Board. We would like to insulate the walls of our home. The interior of these walls have been fully restored and we would rather not remove these. We have heard that blown in insulation can create a serious moisture problem and create rot in the sills over time. We feel that we are the current caretakers and do not want to mess this beautiful home up in any way. Is there a way to blow insulation in from the exterior without much damage? We plan to have the exterior of the house painted this season and would like to address our heat loss problem first. Are there products that might be better suited for our home? We also are concerned with the health of our family and indoor air quality. We are trying to make our home"green" and more comfortable in the long New England winters. Thanks for any help.