Insulation makes a home more energy efficient which decreases the amount of power that is used and can save on heating costs. However, the insulation that is chosen can also have a big impact on the environment.
Using recycled materials can help cut down the demand for the world’s natural resources. The use of a renewable raw material can also decrease the need for landfill which is filling up at an alarming rate.
Fossil Fuels
Fossil fuels are carbon-rich materials such as coal, crude oil and natural gas. They’re made from the fossilized remains of plants and animals that died millions of years ago, compressed and heated underground to form these energy sources. When they’re burned, they release greenhouse gases that blanket the Earth and trap its heat, causing global warming.
Fosil fuels are non-renewable resources that require massive amounts of energy to produce. They also generate harmful air pollutants. Coal-fired power plants, for example, are responsible for 35 percent of dangerous mercury emissions in the United States and two-thirds of sulfur dioxide emissions, which contribute to acid rain. They emit large amounts of soot and particulate matter, as well as poisonous carbon monoxide, which can cause respiratory illness with sustained exposure.
The combustion of fossil fuels releases carbon dioxide, a greenhouse gas, which causes the planet to warm. It also changes ocean chemistry, increasing the acidity and decreasing the availability of calcium carbonate, which is essential for many marine organisms.
In addition to their impact on the climate, obtaining and transporting fossil fuels takes up a considerable amount of natural resources. Fossil fuels must be mined or drilled out of the ground, then transported to processing and distribution centers via pipelines, trucks and tanker ships. Ships delivering fossil fuels often inadvertently spread invasive species in ballast water or as biofouling on their hulls, which can displace native species and disrupt ecosystems.
Chemicals
Many insulation products are made with a range of chemicals, and some of these are harmful to the environment. Chemicals used in the manufacturing process of plastic insulation materials can cause greenhouse gases, and the production of foam plastic insulation also releases toxic substances into the air. The chemicals found in some common insulation materials can even cause harm to workers in the manufacturing plants.
Fossil fuel-derived chemicals such as chlorine and chlorofluorocarbons destroy the earth’s protective ozone layer, while polystyrene, spray polyurethane foam, phenolic, and polyisocyanurate insulations contain blowing agents that are very potent greenhouse gases. The production of these chemicals requires fossil fuel energy, and they require the use of solvents that are derived from petroleum (see discussion on embodied energy below).
Fiberglass insulation, which is a mixture of glass fibers, uses formaldehyde binders that are bad for our health. In addition, most fiberglass is not accepted for recycling because it contains some cellulose, which can require heavy machinery to harvest.
Several manufacturers are developing insulation that does not need any binders, and that does not use blowing agents such as HCFCs or HFCs. These new insulations are expected to have lower global warming potential values. Owens Corning, for example, is introducing a fiberglass insulation called Miraflex that does not use any binder, and it will be manufactured with a new type of binder that does not release phenol formaldehyde into the air. Another manufacturer, Resin Technology Company, has developed a closed-cell water-blown polyurethane product that does not use any HCFCs or HFCs and can be used for residential insulation.
Recycled Materials
Some insulation materials are made from recycled waste products. For example, cellulose insulation is made from recycled newspapers. Fiberglass batts often contain recycled glass or plastic resin. Some manufacturers use recycled material in their extruded polystyrene (XPS) insulation. For instance, Amoco Foam Products uses 50% recycled resin in its XPS product called Amofoam-RCY.
Loose-fill insulation is typically blown in place by contractors experienced at achieving the correct density and R-value. Cellulose, fiberglass, and mineral (rock or slag) wool are blown in this way. Mineral wool typically has 75% post-industrial recycled content.
Other loose-fill insulations include vermiculite and perlite. These can be poured into wall cavities or unenclosed spaces, such as attics.
Most insulation materials are rated for their thermal resistance and R-value, but the embodied energy that went into their production should be taken into account as well. Embodied energy is the amount of energy used to make a specific quantity of a given building product, such as an insulation bag or a piece of cardboard.
Some types of insulating materials are more energy efficient than others, and it is important to consider the R-value and embodied energy for any particular application. For instance, it is not usually cost-effective to fill steel framing with insulation, because it will significantly reduce the average wall R-value. Instead, a layer of insulating sheathing over the steel framing is a more effective approach.
Cork
Cork is a natural, renewable, sustainable and recyclable material that can be turned into many different types of products. It is also hypoallergenic, fire retardant, and termite resistant. It is lightweight, rot resistant and buoyant. It can be carved into shapes for decorative purposes. Its insulating and energy saving properties make it a great choice for insulation in buildings. Cork derivatives are used in floor coverings, wall coverings and other materials for decoration.
The forests that produce cork are also home to a unique and fragile ecology. They provide habitats for rare species and are among the 36 most important ecosystems in the world for preserving biodiversity. They are an example of the multifunctionality of the natural environment and provide an important source of income for thousands of people in Portugal, Spain, Morocco and other countries where cork is produced.
The cork oak tree has evolved to protect itself from harsh climate conditions in the Mediterranean forests. The outer bark consists of water-resistant cells that separate the thick, hard exterior layer from the soft inner bark. To harvest the cork, the bark is stripped from the trees using a special hatchet without damaging the interior bark. The process is done by hand and the freed portions are called planks, which can be cut into various sizes to serve as different products. The most common products are cork stoppers for bottles of wine, but the material has many other uses. It is used in flooring, shoes and containers, acoustic and vibration insulation, and seals and joints (Gil and Moiteiro, 2003).