✔ Be aware of the different types – Insulation comes in many different forms. The type best suited to each home depends on the local climate, space limitations, budget concerns, and the preferred installation method. The US Department of Energy (DOE) separates insulation into the following form categories:
- Blankets – Batts or rolls of fiberglass or rock wool. Cotton fiber batts are also available in some areas. Blankets work well for do-it-yourself projects when space is relatively free from interior obstructions.
- Loose-fill or Spray-applied – Usually blown in or sprayed-in- place with professional equipment, available substances include rock wool, loose fiberglass, cellulose, or polyurethane foam.
- Rigid insulation – Among several types of condensed foam board. This type of insulation is best suited for maximizing R-value with minimal thickness.
- Reflective barriers – Foil-faced materials designed to be particularly effective in preventing heat transfer through radiation.
✔ Choose the most appropriate material – Insulation is made from a variety of different materials. These are the most common materials on the market today.
- Cellulose – Cellulose is made primarily from recycled paper. About 75% of the material used to make cellulose is post-consumer waste paper, giving it the highest average recycled content of all insulation types.
- Recycled Cotton – The cotton is made mostly of recycled denim. While cotton is a natural, renewable resource, unless it is organic, its growing and processing have negative effects on the environment. Since most denim won’t be organic, this is something to keep in mind at the time of purchase. Cotton insulation will usually be treated with a small amount of boron which acts as a flame retardant. Cotton insulation has a similar R-value to cellulose for a similar thickness of insulation.
- Fiberglass – Fiberglass is made of silica sand and recycled glass. These are both abundant resources. Producing fiberglass insulation requires melting the materials in a fossil fuel– burning furnace. Be sure to check the label to see if it contains formaldehyde – this can possibly cause cancer.
- Spray Polyurethane Foam (SPF) – Foams have greater environmental impacts than other types. This is due to extraction, refining and the transport of raw materials such as natural gas and petroleum. SPF is available in either open- cell foam or closed-cell foam. In open-cell foam, the tiny cells of the foam are not completely closed. This makes the material structurally weaker and it will have a lower R-value. Although this type of SPF is generally less expensive. In closed-cell foam, the cells are closed and more closely packed together. This results in a higher R-value, but more material is needed, therefore it can be more expensive.
- Mineral Wool (Rock Wool or Slag Wool) – Mineral wool is an eco-friendly material. It doesn’t require flame retardants, it is made from abundant materials, it is moisture resistant, and 75%– 90% recycled content.
✔ Increase the amount in your attic – Increasing the insulation in your attic is one of the most cost-effective ways to reduce a home’s heat loss through the roof and the building shell in the winter and heat gain during the summer.
✔ Determine your insulation R-value – All insulation has an R-value rating, usually from R-7 to R-50. This rating indicates its resistance to heat flow from a warm area to a cooler area. Insulations calculators, which can advise on the proper levels for your climate are readily available online.
✔ Ensure proper attic ventilation – It is important to assess your attic’s ventilation. The proper exchange of indoor air with outdoor air will allow excess heat to escape in the summer so your cooling system won’t use more energy than needed and will also prevent moisture from condensing inside the attic.