I'm beginning the renovation of a two-story historic home built in 1869 in Mobile, AL. The "Croom House" is a landmark on one of the oldest public squares in the city. The house was owned and inhabited by the Croom family until I purchased it from the fifth generation last year. My question concerns the issue of historic preservation versus the value of energy efficiency. The interior walls are all plaster except for the ceilings which were covered in wallboard at some point in the past. Many of the plaster walls are in good shape but others have suffered significant cracking and in some areas, the plaster has turned to a soft, sand-like material. I have been told that I should salvage and repair all of the plaster to preserve the historic nature of the house. But, with the rising energy costs to deal with, I'm having trouble deciding what to do. I would love to be able to replace the wiring and insulate the exterior walls but insulating presents other issues due to the lack of a vapor barrier. Bottom line question is two fold. Does tearing out the existing plaster and lath to allow for insulation, wiring upgrades, etc. offer enough energy savings to offset the loss of the historic value the walls provide to the home? Is there a way to save the walls and still improve the energy efficiency of the home?