Replies

1. GBA Editor
   Martin Holladay | May 29, 2009 07:07am | #1

   Dave,
   It sounds like you have two questions:
   1. How does one insulate a historic home? and
   2. How does one "green" an old home?

   I'll try to tackle both questions.
   1. Methods of insulation depend on the construction details of the old home. Here in Vermont, a lot of older houses have stone-walled basements, wood-framed walls, and unheated attics. To insulate such a house, most builders would recommend closed-cell spray polyurethane foam on the interior of the basement walls (protected by a thermal barrier), dense-packed cellulose insulation in the walls, and deep cellulose insulation on the attic floor.
   However, a brick building in Baltimore would require other strategies. In short, insulation methods depend on the age and construction details of your house.

   2. To "green" an older home, it will, of course, be necessary to upgrade the insulation. In addition, the following measures will usually be necessary:
   a. Careful air-sealing work to reduce the home's air-exchange rate. Tell your builder that you want "blower-door-directed air sealing."

   b. Improvements to the existing windows. In cold climates, the standard recommendation is to install low-e storm windows and to improve the weatherstripping of the existing windows.

   c. In some cases, it may be necessary to replace the existing furnace, boiler, or air conditioner. Air-sealing and insulation improvements will lower the heating and cooling load of your home, so smaller equipment will work. Modern furnaces, boilers, and air conditioners are usually more efficient than older models.

   This is only an outline to get you started. Other readers are invited to chime in with their own advice.