Insulation and Sealing Air Leaks

Checking your home's insulation is one of the fastest and most cost-efficient ways to reduce energy waste and make the most of your energy dollars. A good insulating system includes a combination of products and construction techniques that protect a home from outside temperatures—hot and cold, protect it against air leaks, and control moisture. You can increase the comfort of your home while reducing your heating and cooling needs by up to 30% by investing just a few hundred dollars in proper insulation and sealing air leaks.

Heat always flows from warm areas to cooler ones. That means that in Alaska in the winter, the heat from your home is trying to move to the outdoors. In warmer climates, it also means that in the summer heat from the outdoors is trying to move into an air-conditioned home. Although any of the principles of insulation apply to both situations, this book will focus on reducing heat loss. This process can only be slowed down by something that will resist this movement.

Air is a very poor conductor of heat, which is why it is a good resistor. When air pockets are trapped inside insulation or between panes of glass they retard the flow of heat. Therefore, it's not the substance itself (glass fiber, cellulose, rock wool or foam, for instance) that slows heat loss, but the trapped pockets of air that are in or between these materials.

Insulation

R-Value

R-value tells you how well a material resists heat flow. Resistance (R) to eat flow is measured by how many hours it takes one BTU to go through one square foot of a material experiencing a one degree temperature difference. The higher the R-value, the greater the resistance.

R-values vary with different types of materials. Therefore, how well insulation performs is more accurately measured by its R-value than by inches or thickness.

Although insulation can be made from a variety of materials, it usually comes in four types; each type has different characteristics.

Rolls and batts—or blankets—are flexible products made from mineral fibers, such as fiberglass and rock wool. They are available in widths suited to standard spacing of wall studs and attic or floor joists: 2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 and R-21 products.

Loose-fill insulation—usually made of fiberglass, rock wool, or cellulose—comes in shreds, granules, or nodules. These small particles should be blown into spaces using special pneumatic equipment. The blown-in material conforms readily to building cavities and attics. Therefore, loose-fill insulation is well suited for places where it is difficult to install other types of insulation.

Rigid foam insulation—foam insulation typically is more expensive than fiber insulation. But it's very effective in buildings with space limitations and where higher R-values are needed. Foam insulation R-values range from R-4 to R6.5 per inch of thickness (2.53 cm), which is up to 2 times greater than most other insulating materials of the same thickness.

Foam-in-place insulation—can be blown into walls and reduces air leakage.

Where to insulate Insulation should be installed in areas that separate heated spaces from unheated spaces. That includes all exterior walls, attics, floors over unheated areas, heated basement walls and overhangs. Other areas that should not be overlooked include exterior walls between levels in a split-level home; rim joist area; knee walls next to heated attics; walls next to unheated garages, storage rooms and utility rooms; dormer and cantilever walls and ceilings; and floors over vented crawl spaces. In other words the insulation should completely surround your home, with the only openings being doors, windows and vents.

Sealing Air Leaks Warm air leaking into your home during the summer and out of your home during the winter can waste a lot of your energy dollars. One of the quickest dollar-saving tasks you can do is caulk, seal, and weatherstrip all seams, cracks, and opening to the outside. You can save 10% or more on your energy bill by reducing the air leaks in your home.
	Sources of Air Leaks in Your Home Areas that leak air into and out of your home cost you lots of money. Check the areas listed below. Dropped ceiling Recessed light Attic entrance Sill plates Water and furnace flues All ducts Door frames Chimney Flashing Window frames Electrical outlets and switches Plumbing and utility access

Tips for Sealing Air Leaks

• Test your home for air tightness. On a windy day, hold a lit incense stick next to your windows, doors, electrical boxes, plumbing fixtures, electrical outlets, ceiling fixtures, attic hatches, and other locations where there is a possible air path to the outside. If the smoke stream travels horizontally, you have located an air leak that may need caulking, sealing, or weatherstripping.
• Caulk and weatherstrip doors and windows that leak air.
• Caulk and seal air leaks where plumbing, ducting, or electrical wiring penetrates through exterior walls, floors, ceilings, and soffits over cabinets.
• Install insulating gaskets behind outlet and switch plates on exterior walls.
• Look for dirty spots in your insulation, which often indicates holes where air leaks into and out of your house. You can seal the holes by stapling sheets of plastic over the holes and caulking the edges of the plastic.
• Install storm windows over single-pane windows or replace them with double-pane windows.
• When the fireplace is not in use, keep the flue damper tightly closed. A chimney is designed specifically for smoke to escape, so until you close it, warm air escapes—24 hours a day!
• For new construction, reduce exterior wall leaks by either install house wrap, taping the joints of exterior sheathing, or comprehensively caulking and sealing the exterior walls.