- In unfinished attic spaces, insulate between and over the floor joists to seal off living spaces below. *
- In finished attic rooms with or without dormer, insulate:
- 2A - Between the studs of "knee" walls;
- 2B - Between the studs and rafters of exterior walls and roof;
- 2C - Ceilings with cold spaces above;
- 2D - Extend insulation into joist space to reduce air flows.
- All exterior walls, including:
- 3A - Walls between living spaces and unheated garages, shed roofs, or storage areas;
- 3B - Foundation walls above ground level;
- 3C -Foundation walls in heated basements, full wall either interior or exterior.
- Floors above cold spaces, such as vented craw spaces and unheated garages. Also insulate:
- 4A - Any portion of the floor in a room that is cantilevered beyond the exterior wall below;
- 4B - Slab floors built directly on the ground; **
- 4C - As an alternative to floor insulation, foundation walls of unvented crawl spaces;
- 4D - Extend insulation into joist space to reduce air flows.
- Band joists.
- Replacement or storm windows, and caulk and seal around all windows and doors.
*Well-insulated attics, crawl spaces, storage areas, and other enclosed cavities should be ventilated to prevent excess moisture build-up.
**For new construction, slab on grade insulation should be installed to the extent required by building codes, or greater.
Courtesy of the DOE