You can reduce your home’s heating and cooling costs through proper insulation and air sealing techniques. These techniques will also make your home more comfortable.
Any air sealing efforts will complement your insulation efforts, and vice versa. Proper moisture control and ventilation strategies will improve the effectiveness of air sealing and insulation, and vice versa.
Adding Attic Insulation
Attic insulation installation
Loose-fill or batt insulation is typically installed in an attic. Loose-fill insulation is usually less expensive to install than batt insulation, and provides better coverage when installed properly. See more on different types of insulation. Before insulating, seal any air leaks and make roof and other necessary repairs. If it is located in a conditioned part of the house, also remember to insulate and air seal your attic access.
Insulate and air seal any knee walls — vertical walls with attic space directly behind them — in your home as well. In addition, if you’re building a new home or remodeling, make sure any attic decking that provides additional storage space or a platform for a heating and/or cooling unit or hot water tank is raised above the ceiling joists to leave room for adequate insulation. If the air distribution system is not within the conditioned space but within the attic, insulating the rafters will enclose the distribution system. Finally, if you live in a hot or warm climate, consider installing a radiant barrier in your attic to reduce summer heat gain.
Your heating and air conditioning typically accounts for 49% or more of your homes energy cost.
If the ducts in your home are in unconditioned space, have them sealed and insulated. If you’re building a new house, place ducts in the conditioned space to avoid the energy losses associated with most duct systems.
INSULATING FLOORS ABOVE UNHEATED GARAGES
When insulating floors above unconditioned garages, first seal all possible sources of air leakage. This strategy has the added benefit of minimizing the danger of contaminants (from car exhaust, paint, solvents, gardening supplies, etc.) in the garage migrating into the conditioned space. Also install an air barrier to prevent cold air in the garage from “short circuiting” the insulation underneath the subfloor.
LOOSE-FILL AND BLOWN-IN INSULATION
Loose-fill insulation consists of small particles of fiber, foam, or other materials. These small particles form an insulation material that can conform to any space without disturbing structures or finishes. This ability to conform makes loose-fill insulation well suited for retrofits and locations where it would be difficult to install other types of insulation.
The most common types of materials used for loose-fill insulation include cellulose, fiberglass, and mineral (rock or slag) wool. All of these materials are produced using recycled waste materials. Cellulose is primarily made from recycled newsprint. Most fiberglass contains 20% to 30% recycled glass. Mineral wool is usually produced from 75% post-industrial recycled content. The table below compares these three materials.
RADIANT BARRIERS AND REFLECTIVE INSULATION
Unlike most common insulation systems, which resist conductive and sometimes convective heat flow, radiant barriers and reflective insulation work by reflecting radiant heat away from the living space.
Radiant barriers are more effective in hot climates, especially when cooling air ducts are located in the attic. Some studies show that radiant barriers can lower cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it’s usually more cost-effective to install more thermal insulation.