Attic Insulation 101

attic-insulation-101With the arrival of cooler weather here in the San Francisco Bay Area, homeowners looking to reduce their winter utility bills will be well served to consider upgrading their existing attic insulation. Before you can enjoy these savings along with greater indoor comfort levels, you’ll need to select the best type of attic insulation to meet your needs. Although there are additional specialty types, blanket batts or rolls, blown in, or sprayed insulation styles are each available in a number of different materials and are the most readily available options.

Blanket Insulation – Rolls or Batts

One of the most common and lowest cost insulation types is blanket rolls or batts which come prefabricated to fit the gaps between standard structural components of your attic. They are available with or without a facing designed to serve as a vapor and air barrier, and can be purchased in standard lengths or long rolls that can be cut to fit.

Fiberglass and cotton are the most common materials used to produce blanket insulation and both provide similar insulating qualities per inch of thickness. Cotton is a more environmental friendly option than fiberglass, but has a higher price tag; traditional fiberglass batting remains the lowest cost option for attic insulation.

A significant disadvantage to any blanket insulation is its inability to completely fill all gaps or spaces within your attic. Although installation can be completed by do it yourself minded homeowners, any upfront savings in cost and labor may be lost over time in the form of higher energy costs.

Blown In Insulation Fills the Gaps

Fiberglass, wool, or cellulose (another environmentally friendly option) materials can be professionally blown into place using a large machine that shoots small chunks of material through a hose and into your attic. As opposed to batting, blown in material will provide superior insulating value, as all gaps and spaces will be completely covered and filled.

Blown in insulation compares favorably with blanket styles in terms of overall cost, with the slightly higher cost of blown materials generally coming back to you in the form of greater energy savings.

Sprayed Foam Provides the Highest Insulating Value

Inch per inch, sprayed in foam insulation can provide close to double the insulating value as traditional fiberglass batting. It is also excellent at filling all spaces and gaps, and can even serve as an effective vapor barrier in many instances. You have a number of different types of foam to choose from; practically all are now free from the harmful chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs) present in the foams of yesteryear.

Sprayed insulation can be an excellent choice for homeowners willing to accept the higher upfront costs, some of which are recuperated through eliminating the need for a separate vapor barrier. Spray foam also allows you the ability to move your building envelope to the roof line instead of the attic floor, providing additional conditioned space that can be helpful in homes where the HVAC unit is housed in the attic, or if you plan to finish your attic space at a later time.

Talk to a Pro for Help Choosing the Most Appropriate Insulation

The best type of attic insulation can be chosen by considering all the specifics of the job as well as the available budget. Blanket, blown in, and sprayed foam insulation types all have unique advantages and disadvantages; talking with a professional can be helpful in selecting the most appropriate type and material to meet your needs.


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