70 ENERGY SAVING FEATURES

INSULATION

Recommendations for insulation vary based upon the amount and type of glass, the heating / cooling equipment efficiency and the location.

Ceiling and Attic Insulation (Items 17, 18, 19, 29, 21, 34 & 35)

Ceilings and attics can be insulated in several different ways using batts and blown-in insulation. Recommendations for the amount of insulation are R-30 to R-49.

Cathedral Ceiling Insulation (Items 37 & 38)

Batts or foam boards may be used to insulate cathedral ceilings but care must be used to provide adequate air-flow between the roof and the insulation. Recommended insulated values are R-30 to R-38.

Wall Insulation (Items 1, 2, 3, 4, 9, 10, 11, 13, 42 & 45)

Recommended wall insulation value is R-18. Many different types of insulation can be used to insulate the wall. These can be: fiberglass or rock wool batts (with or without paper-facing); sprayed on foam or cellulose; fiberglass, rock-wool or cellulose loose-fill, or rigid foam. Foam sheathing on the outside will add to the insulating value of the wall. Other items illustrated on the display include avoiding loose fill insulation settling, using a T-strap for corner bracing and running the wiring through notches at the sole-plate to not disturb the insulation.

Floor Insulation (Items 49, 50, 51 & 58)

The recommended amount of insulation in floors over unconditioned spaces is R-19 to R-25. The insulation should be supported and the vapor barrier should face upward. It is very important to also insulate the band- and rim-joists.

Basement Insulation (Items 56 & 57)

Conditioned basement walls below uninsulated floors should be insulated with a minimum of R-11. This can be done by insulating the exterior with 1'-3" of extruded polystyrene, insulating the interior wall by installing behind interior framing or with furring strips, or by using insulated concrete forms. The three keys to an effective energy efficient basement are moisture control, airtight construction and insulation coverage.

Crawlspace (Items 52 & 53)

The main components in crawlspace insulation are moisture control and insulation. It is extremely important to cover the entire crawlspace floor with a sealed, continuous layer of 6-mil polyethylene cover. Insulate crawl space walls only if the crawl space is dry all year, the floor above is not insulated, and all ventilation to the crawl space is blocked. The recommended amount of insulation on the crawlspace walls is R-19. If floor insulation is provided and the crawlspace is vented, a minimum of two vents (with at least 1 ft² for each vent) should be should be provided. These should be located on opposite sides of the crawlspace to provide for cross ventilation. The total open area of all vents should be at least 1 ft² of vent per 1500 ft² of floor area of the floor area if a continuous ground cover is installed. If a ground cover is not installed, the vent area should be 1 ft² of vent per 150 ft² of floor area.

Ductwork (Items 59, 60, 61, 62 & 63)

Typical duct systems lose 25 to 40 percent of the heating or cooling energy put out by the central furnace, heat pump or air conditioner. This can be reduced by: running the ducts in heated/cooled spaces, insulating the ducts and sealing the ducts to prevent air leakage (in or out). Ducts must be insulated to R-5 (or R-8 if located on the exterior of the building). All joints, seams and connections must be securely fastened and sealed with gaskets, adhesives, mastic-plus-embedded fabric or approved tapes. Standard duct tape is not recommended.

Air Infiltration / Air Leakage Control (Items 14, 15, 16, 30, 31, 40, 41, 43, & 44)

Air infiltration can account for between 30% to 50% of a home's heating and cooling costs and contribute to problems with moisture, noise, and dust. Reducing infiltration can significantly cut annual heating and cooling costs. Major ways of reducing infiltration are by using a house wrap; using gaskets at joints and behind electrical switch and outlet plates; and caulking / sealing joints, piping and wiring penetrations and electrical box openings. Air infiltration barriers are sometimes called weather-resistive barriers however they should not be confused with vapor barriers because they must allow water vapor to pass through them. Significantly more water vapor travels through a wall by air leakage through cracks and openings than by diffusion through the walls so air infiltration control also controls potential moisture problems.

Vapor Retarder (Items 5, 6, 7, 8, 12, 50 and 53)

A vapor retarder is used to keep moisture vapor from the warm side moving to the cold side of a wall, floor or attic and potentially condensing inside them. This would create an ideal area for mold to grow and damage to occur. The vapor retarder can be made of insulation craft-paper backing or more commonly 4-6 mil polyethylene plastic sheeting. It is important to have the vapor retarder on the inside of most of the insulation and for it to be tightly sealed to prevent the moisture from leaking through holes and other openings.

Windows and Doors (Items 13, 46, 47 and 48)

Windows and doors are the second largest source of heat loss or gain in a house. Consider an insulated metal or fiberglass door if possible. The area around the window frames should be insulated and sealed and the header should be insulated. Several different types of new windows are available which can greatly reduce the energy losses and make the house more comfortable. They are designed to keep the heat in on cooler days and keep the heat out on warmer days. The windows should have a U-factor of 0.40 or less and a Solar Heat Gain Coefficient (SHGC) of 0.55 or less. These usually have non-metal frames such as wood, vinyl or fiberglass; at least 2 panes and a low-e coating.

Water Heater (Items 64, 65, 66, 67, and 68)

Water heating accounts for between 15 and 25% of the energy consumed in houses. This can be reduced by selecting the appropriate water heater type, using efficient system design and insulation and reducing the amount of hot water consumed. Insulating the water heater is one of the best energy savings techniques. The water heater insulating jacket should be at least R-11, sealed at the seams and edges, and cover the heating access plates for electric heaters. A heat trap is needed on both the inlet and outlet of the heater. Typical methods used for creating heat traps are “U” or “rams horn” bends in the flexible pipe connections or installing pipe nipples with integral traps.

Lighting (Items 22, 23 and 24)

Energy efficient lighting focuses on methods and materials used in quality and efficiency of lighting. Advanced lighting designs such as compact florescent lamps can greatly reduce the cost of lighting. Insulating contact recessed can lights also improve the insulating value of the ceiling. Air-tight ICT can lights greatly reduce the amount of infiltration in the building.

Ventilation (Items 25, 26, 27, 28, 29, 32, 36, 38, 54 & 55)

All homes need ventilation to reduce indoor moisture, odors and other pollutants. A whole house fan can potentially reduce the need for air conditioning but it must be sized properly, the attic must be adequately ventilated and penetrations between the attic and living space should be sealed.

It is especially important to adequately ventilate the attic to remove moisture and heat and ventilate between the insulation and the roof to reduce the roof temperature. A rule of thumb is to use 1 square foot of net vent opening for every 150 square feet of insulated ceiling (or 300 ft² if the ceiling has a vapor barrier). The openings should be evenly divided between ridge and soffits. It is questionable if electrically powered roof ventilators consume more power than they save.