How Much Insulation Should You Have in the Attic? Most heat loss is through the attic area. If your attic has some insulation, measure how deep it is and check the tables below to find out how much you need to meet R-30 the minimum 'R' value recommended for BGE customers.

Increasing the level of insulation from 2-3 inches (R5) to 8 -14 inches (R30) can save $95 to $145 per year for every 1,200 square feet of ceiling area.

Determine the Square Footage of Your Attic Space
For rectangular space, measure the length and width to the nearest foot and multiply them together.

If your attic is not rectangular, break it down into rectangles. Find the area of each. Then add the areas together to get the total.

Length x Width = Area
1.              x            =         
2.              x            =         
3.              x            =         

Insulating Your Attic Space
Install batts or blankets of insulation between the joists or trusses. Or lay batts over existing insulation if you need more. Don't add a vapor barrier if you have existing insulation.

What are Vapor Barriers?
Vapor barriers will reduce the chance of water vapor condensing and collecting in your new insulation or on the beams and rafters of your house. This is important because moisture can damage the structure of your house and reduce the effectiveness of the insulation. If you are installing batt or blanket insulation in an uninsulated attic, buy the batts or blankets with the vapor barriers attached. Install them with the vapor barrier side toward the living space. If you install additional insulation over existing insulation, use a batt with no vapor barrier. When vapor barriers are placed between existing and added insulation, moisture is trapped, which reduces the insulation value and could cause moisture damage to the house.

Remember:

• Don't cover recessed light fixtures with insulation.
• Do not let insulation touch flue vents or block eave vents.
• Do not block air openings for heating systems.
• Always follow the manufacturer's instructions.

Step-by-Step Instructions:

Step 1 Lay temporary flooring (use plank or plywood piece) across joists and hang a temporary work light. You should leave insulation in its wrapper until you're ready to use it. Insulation is packaged in a compressed state and expands greatly when the wrapper is opened.

Step 2 Begin laying batts or blankets at the outer edge of the attic space and work towards the center (this will allow more headroom in the center of the attic for whatever cutting and fitting there is to be done). Lay in long runs first and use the leftovers for shorter spaces. Insulation should be installed around wiring taking care not to disturb it. Be sure to butt insulation tightly at joints for a complete barrier to heat flow.

Step 3 Insulation should extend far enough out to cover the top plate of the walls but should not block the flow or air from the eave vents. For best results, install ventilation baffles at the inside of the eaves.

Step 4 Insulation must be kept three inches away from recessed light fixtures unless the fixture is marked 'I.C.' (insulated ceiling) - a fixture designed for direct insulation contact. Insulation placed over an unrated fixture, like a recessed light, may cause it to overheat and start a fire. Fill the space between a masonry chimney and wood framing with noncombustible material such as unfaced Fiberglas insulation. If you are insulating around a metal flue, do not place the insulation flush to the flue. Always leave at least a three-inch space.

Step 5 Ends of batts should be cut to fit snugly around cross bracing. If a second layer of insulation is needed and the cavity has been completely filled, the additional layer should be placed at right angles to the joists.

Step 6 When adding to existing insulation, unfaced Fiberglass blanket is recommended. Owens-Corning's R-25 Attic Blanket(C) is ideally suited for this application. If the unfaced type is not available, use the faced type but remove the vapor barrier or slash it freely with a knife (then install the insulation with the slashed facing down). Do not leave faced insulation exposed. The facings on standard kraft- and foil-faced insulations will burn.