How Does Insulation Conserve Energy?
Referenced from Home Guides
Insulation reduces the exchange of heat through a surface such as a wall, attic, duct or roof. In a well-insulated home, less warm air escapes from the house during the winter, and less cool air escapes during the summer, reducing the amount of energy needed for heating and cooling. Improving the insulation in older structures may lower your annual heating and cooling bill by up to 20 percent!
Insulating Walls, Floors and Attics
The outer shell, or envelope, of your home is the barrier that prevents the temperatures of the inside and outside air from equalizing. The better insulated the walls, floors and roof are, the less energy your heating and cooling systems have to use to warm or cool the air in your home. Since heat rises, insulating your roof is especially important to keep warm air inside in cold climates.
Sealing Air Leaks
Even walls with good insulation can let warm or cool air escape through cracks and gaps around windows and doors. Drafty homes require more power to heat and cool than tight homes, so save energy by caulking and weather-stripping to stop air leaks. In older homes, it's virtually impossible to seal the house too tightly; in most cases, because of the construction methods used, there will still be enough fresh air to maintain good ventilation after sealing the biggest leaks.
In homes with central heating and air-conditioning units that force air through a duct system, leaking ducts may lower efficiency by up to 20 percent. Seal and insulate all of the ducts in your house to let the warm and cool air get where it's supposed to go as efficiently as possible. Good insulation is even more important when the ducts travel through unfinished areas like attics or basements. Finally, seal the areas around the registers to keep air from leaking behind the wall or under the floor.
While most insulation reduces heat transfer by physically blocking it, reflective insulation, also called a radiant barrier, is installed on the attic floor, where it reflects the heat radiated into the attic by a hot roof and prevents it from entering the living space below. While reflective insulation has some value in lowering heating bills, its main purpose is to keep the house cool in hot climates.