- Ceilings below an unheated area.
- "Knee" walls of a finished attic level room.
- Floor of a crawl attic.
- The sloping portion of the roof in a finished attic. Leave an airspace between insulation and roof.
- Exterior walls.
- Floors above cold crawl spaces. Floors above a porch or an unheated garage.
- Walls of a heated basement.
Fig. 19-2. Where to insulate.
In addition to the need for insulation of the building shell (exterior walls, ceilings, and floors), all hot-water pipes and heating and cooling ducts that pass through unheated portions of the house (such as a crawl space, garage, or unfinished attic) must be insulated. Most houses usually have no more than 1 or 2 inches of insulation wrapped around ducts in unheated areas. Because of increasing fuel costs, this is considered minimal for most areas, and additional insulation can usually be justified. Check the condition of the insulation. Are there any loose, torn, or missing sections? Also, if there are any exposed duct joints, check them to see if they are sealed tightly. When the ducts are used exclusively for air conditioning or serve a dual function (such as heating and air-conditioning), the outside of the insulation should be covered with a vapor barrier to prevent condensation. A vapor barrier, however, is not needed on ducts used only for heating. If there is a vapor barrier on the ducts, check its condition. Look for torn and missing sections. All vapor-barrier joints must be tightly sealed.
If the domestic hot water is produced in a tank-type water heater located in an unheated area, the tank should be covered with an insulation jacket. These jackets can be purchased in most building-supply or hardware stores. Although tank-type water heaters are normally insulated by the manufacturer, by installing an outer insulation jacket, you will further reduce heat loss and thereby minimize the energy needed to maintain the desired water temperature. The temperature of the hot water should not exceed 140° F. (See chapter 16.) Temperatures in excess of 140° F are not only wasteful of energy but will also shorten the life of the water heater.
While in the attic checking the insulation, see if the area is adequately ventilated. As discussed in chapter 9, attic ventilation is necessary not only to prevent condensation problems during the winter months but also from an energy-conservation point of view to reduce the heat load on the structure during the summer. Because of trapped air, attic areas can become excessively hot during the summer, reaching temperatures of about 150° F. If there is an air-conditioning blower coil located in the attic, the high temperature will tend to lessen its efficiency of operation.
Ventilation in an attic should be provided by at least two vent openings located so that air can flow in one opening and out of the other. Vents in the eaves and at gable ends are better than gable vents alone. One of the most effective methods for ventilating the attic is a combination of vents in the eaves and a continuous ridge vent. Remember, the attic must also be adequately ventilated during the winter. As long as the attic is adequately insulated, the benefits of ventilation greatly exceed any fuel savings that might result from blocking the vent openings.
Most homes with single-pane windows will benefit by the installation of storm windows. (See chapter 5.) A storm window, whether a storm sash, panel, or combination unit, reduces the heat loss through a single-glazed window by about 50 percent. In cold climates, it also adds to physical comfort by reducing an apparent draft. Body heat radiates toward a cold surface. Also, warm air hitting a cold surface loses its heat, becomes dense, and falls to the floor. This combined effect creates what appears to be a draft to someone sitting or standing near the cold surface (window). If the storm window is a sash or combination unit (both of which cover the window frame), it also helps reduce cold-air infiltration through the movable and fixed joints around the window.
Basically, a storm window is effective because it traps a layer of air between itself and the window. This dead air space acts as an insulator and thus reduces heat loss. If installing storm windows is not economically justified because you are planning to move or your budget does not presently permit the purchase of storm windows, you can still make your windows energy efficient. Simply cover them with plastic sheets and secure the edges with tacks, molding strips, and caulking. Although temporary, these inexpensive homemade storm windows are an effective approach to reducing heat loss. They will more than pay for themselves in fuel savings in the first year.
Caulking and weatherstripping
In a well-insulated house with thermal-pane or storm windows, air leakage is the greatest source of heat loss. To conserve energy further by reducing the cold-air infiltration during the winter and the loss of air-conditioned air in the summer, the movable joints (such as those around windows and doors) should be weatherstripped, and the fixed exterior joints should be caulked. (See chapter 5 for types of caulking compounds.)
Check windows and doors for weather-stripping and tightness of fit. Loose-fitting windows and doors not only lose heat but result in uncomfortable drafts. All window sashes, exterior doors, and interior doors or hatches leading to unheated areas (such as an attic, basement, or crawl space) should be weatherstripped on their sides, tops, and bottoms. Periodically check the condition of the weatherstripping. Over the years, some types of weatherstripping will wear, tear, crack, and generally deteriorate so that replacement is required.
The condition of the caulking on the exterior joints should be checked during your energy audit. Specifically, look at the joints (1) between the exterior siding and the window and door frames, (2) at the inside and outside corners formed by the exterior siding, (3) just under the bottom side of the exterior siding and the foundation wall, (4) between dissimilar siding materials (such as a masonry-andshingle wall), (5) where the chimney meets the siding, and (6) where storm windows meet the window frame (except for drain holes at the windowsill). If the caulking is old, brittle, broken, or missing, the joints should be recaulked. Good home maintenance includes an annual check of all exterior joints, particularly in view of rising fuel costs.