Soy-Based Insulation

Homeowners now have the option to insulate their homes with insulation made from soybean oil, known as soy-based insulation. While more expensive than traditional insulation, soy offers a “green” and functionally superior alternative. 

Consider the following advantages offered by soy-based insulation:

• It is safer than most traditional insulation because it contains no formaldehyde or urea. Soy-based insulation will not off-gas any chemical byproducts, and it's applied in a water spray that contains no hydrofluorocarbons or other dangerous chemicals.
• It is made partly from soybeans, which are a renewable resource. Buying soy supports the 600,000 soybean farmers in the United States and, as a substitute for petroleum products, it reduces our dependence on foreign oil.
• One major variety resists moisture, so you don’t have to worry about mold or fungus growth.
• It creates an excellent sound barrier, and boasts a high (Class 1) fire rating.
• Soy-based insulation has a high R-value. According to the United Soybean Board (USB), soy-based insulation provides energy-saving characteristics that are as good as or better than traditional batting insulation. The air-sealing capabilities of closed-cell spray foam is superior to many traditional insulation materials as well.
• It will not degrade or settle.

Typically, soy-based insulation is applied by trained technicians who arrive with tanks. Homeowners, however, can find the material in their local hardware store for around $6 per can and apply it themselves. Either way, a water spray is used to apply soy-based insulation, which subsequently expands to roughly 100 times its original volume, forcing itself into nearby spaces and crevices while it hardens.

Soy-based insulation is available in the following two forms:

• The closed-cell type is dense and rigid, with a bubbly texture. It is strong enough to walk on, and it will improve the structure’s strength in high winds. With an R-value of 5.5, it’s a great insulator, although it costs considerably more than open-cell. Closed-cell insulation has a vapor barrier, meaning that it will prevent or retard the passage of moisture, such as rainwater that tries to pass into the attic through the roof.
• Open-cell is soft, pliable and lightweight, and has a texture similar to broken bubbles. With an R-value of 3.6, open-cell is a lesser insulator than closed-cell, but it’s also less expensive. It has an air barrier but not a vapor barrier, which means that it is generally not used in exterior applications or wherever it might get wet. Moisture will cause open-cell insulation to lose most of its effectiveness, and potentially encourage the growth of mold.

This new type of insulation is more expensive than fiberglass and most other traditional types of insulation. The reason for this premium is that soy-based insulation is still a niche market, having yet to experience the mass production that deflated the price of fiberglass. And, of course, many environmentalists will pay more for a sustainable, renewable form of insulation.

All spray-foam insulation, including soy-based, is green in the sense that it can help homeowners dramatically reduce their energy bills. Soy-based insulation is greener than other insulation material because soy is a renewable resource. But don't be fooled into thinking that soy-based insulation is 100% soy, or even mostly made from soy; as much as 85% of soy-based insulation may be petroleum-based. And, of greater value than the type of insulation used is that the homeowner should first obtain an energy audit performed by an InterNACHI inspector in order to gain a better understanding of what insulative measures should be taken.