The following in an excerpt from the book “The Ultimate Guide to Greening your Home”.
✔ Be aware of the different types of insulation – Insulation comes in many different forms. The form of insulation 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 rockwool. 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 rockwool, 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 insulation material – Insulation is made from a variety of different materials. These are the most common materials on the market today.
- Cellulose – Cellulose insulation is made primarily from recycled paper. About 75% of the material used to make cellulose insulation is post-consumer waste paper, giving it the highest average recycled content of all insulation types.
- Cotton – Cotton insulation is made mostly of cotton. Cotton is a natural, renewable resource. If possible, try to source organic cotton. 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 insulation 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.
- Spray Polyurethane Foam (SPF) – Foam insulations have greater environmental impacts than other types of insulation. This is due to extraction, refining and the transport of raw materials such as natural gas and petroleum. Ozone-depleting compounds are also used in its manufacture.
- 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 insulation level 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 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 the insulation’s resistance to heat flow from a warm area to a cooler area. Insulations calculators, which can advise on the proper level of insulation 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.
Check out the US Green Builders Council’s Green Home Guide for an excellent guide on insulation: http://greenhomeguide.com/know-how/article/buyers-guide-to-green-insulation