Guide to Home Insulation

Whether you’re going through a sweltering summer or a frigid winter, you want to maintain a comfortable home environment without spending too much on heating or cooling. But this sort of energy efficiency is impossible without proper insulation across your ceiling, roof, walls, and floors.

What is Insulation

Insulators are installed in or around structural elements of your home. These products are designed to act as barriers, preventing heat transfers between interior and exterior regions of the property. In the process, they help keep your home at a pleasant temperature all year around, even in extreme weather. According to EPA estimates, proper insulation can save you an average of 15% on your annual utility bills.
Apart from these obvious benefits, insulation is also used to minimize outdoor noise and to prevent outside moisture from entering into your home.

R – Values

If you’re in the market for insulation, then first thing you should pay attention to is the R-value of the product you’re looking to purchase. R-value measures a material’s resistance to heat transfer, the higher the R-value the more difficult it is for heat to transfer through the material. The ideal R-value is entirely dependent on your location the construction of your home, and the type of Heating and Cooling systems in use. If you live in colder or extremely hot climates you should probably opt for a material with a higher R-value.
Similarly, different R-values will be more suited to different structural elements. While R-values for walls, crawlspaces and floors are usually recommended at around R-21 to R-30, R-values for attics and roofs can range from R-30 to R-60.

History of Oregon Energy Codes

Loose-Fill Insulation

Loose-fill insulation comes in the form of small fluffy granules. These particles are blown or poured into wall cavities, unfinished flooring and other irregular areas using specialized equipment. Loose-fill
Loose-fill insulation can be found in a variety of materials including:
This form of loose-fill insulation is made from 70-85% recycled paper, of the kind used for newspapers and cardboard boxes. These waste materials are pulverized, and chemically treated to be fireproof and insect resistant. R-values per inch of thickness are generally around 3.1 to 3.7 per inch of thickness, with final insulation value depending on the depth and density of the insulation.
While the brand and density of the cellulose will affect the price per square foot, insulation for attic walls will usually cost around $1.20 – $1.50 per square foot depending on where the material is being used.
While fiberglass insulation often contains a fair portion of wastepaper as well, at least 20-30% of this material is made up of recycled glass which is melted and spun into dense fibers. R-values for fiberglass are around 2.2 to 2.9 per inch of thickness. While prices can vary, fiberglass is generally less expensive than cellulose at around $0.60 – $1.20 per square foot with costs rising if the material is installed in finished walls.
Mineral Wool
Also known as rock wool insulation, this material is similar to fiberglass in texture but it is spun from metal byproducts produced during the smelting process. Mineral wool has an R-value of 2.2 to 2.9 per inch of thickness. Mineral wool is denser than fiberglass and more difficult to find, because of this it can cost around $0.8 – $1.50 per square foot.

Batt Insulation

Batts are made from loose-fill insulation that has been joined together with a form of adhesive. They are considered to be quite user-friendly and are generally used for DIY insulation projects or vertical installation as they are built to fit between attic beams, wall studs, and floor joists. Although batts can be found in a variety of materials including mineral wool and plastic fibers, they are most often constructed with fiberglass. Fiberglass batts have an R-value ranging from 2.9 to 3.8 per square inch of thickness. Batt insulation costs hover around $0.7 to $1.32 per square inch.


Sprayed Insulation

Sprayed insulation usually comes in the form of polyurethane foam which is used to fill gaps and open cavities in existing walls, although it can also be used on the underside of attic rafters and in floor joists. Once sprayed into a cavity, this form of insulation will set and harden. It then needs to be covered by a barrier (usually drywall) to provide adequate protection during fires.

Sprayed insulation can be found in both open-cell and closed-cell forms. Closed cell foam is denser and has a higher R-value of around 6.2 per square inch of thickness, while open cell foam has an R-value of around 3.7 – 5.6 per square inch of thickness. In accordance with these figures closed cell foam will cost you about $1 – $1.50 per square foot, while open cell foam is far cheaper at $0.44 – $0.65 per square foot.


Amidst all these insulation options, there is one material that you should probably avoid. Vermiculite is a natural mineral which takes the form of small shiny flakes, when baked at high temperatures these flakes expand up to 30 times in size and create a fireproof, durable material that just happens to be extremely resistant to thermal transfer. It is also inexpensive to produce, and abundantly mined.

Up until 1990, vermiculite was still used for insulating purposes across the United States, with materials primarily sourced from one mine located in Libby, Montano. Unfortunately it was later discovered that the vast majority of vermiculite mined from this region had been contaminated with asbestos which has subsequently found its way into many homes across the country.
Exposure to asbestos can cause a variety of nasty symptoms including headaches, shortness of breath and chest pains; it also increases the risk of lung disease, cancer and mesothelioma.

Vermiculite is generally found in a loose-fill form, and it ranges from grayish brown to silvery gold in color. If you suspect that you have vermiculite insulation in your home you must consider whether disturbing the material would cause further airborne particles to spread throughout your home. You are recommended to steer clear of any rooms that contain this material, and to avoid storing any items there as well. If you need to have the substance removed, contact a professional asbestos contractor.

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