Icynene is available as a sprayed or poured foam. Sprayed Icynene is very dense, and is installed in layers into new wall cavities. Poured foam is used in existing walls, where it is installed through tiny holes drilled in the drywall or masonry surface. Polyurethane spray can be used in either of these applications, though nets or forms may be required to hold it in place in a new wall.
Polyurethane is a close cell foam product made from petroleum by-products. The closed cells are filled with HCFC or CFC gases to improve the insulating properties of the foam. Green versions are made from soy, and contain lower levels of these gases.
Icynene is made of castor oil rather than petroleum and features an open cell construction. No gases are present, which reduces the insulating ability of Icynene compared to polyurethane.
When comparing different insulation products, it's important to understand the R-value of each material. R-value is a measure of thermal resistance, with higher R-values linked to more effective types of insulation. According to Energy Savers polyurethane foam has an R-value between 7 and 8 per inch. Icynene.com states that the R-value of Icynene ranges from 3.6 to 4. These values indicate that polyurethane is roughly twice as effective as Icynene when it comes to thermal insulation.
Icynene's primary benefit is its eco-friendly features, including the fact that no petroleum or CFCs are used in its production. This product is also highly resistant to fire and won't lose its effectiveness over time.
Polyurethane is a very effective insulator and is also resistant to fire. It expands slowly to fill a space without over-expanding, which helps prevent possible damage to the structure.
The gases within polyurethane foam insulation tend to escape over time, which can reduce the R-value of this material. These gases are also hazardous to the environment and are associated with ozone depletion.
Icynene is a fairly new product and is more expensive than polyurethane. It can sometimes over-expand and overfill a space, which can cause damage or messy cleanup. It creates such an airtight insulation that it can reduce natural ventilation in the home, making well-designed mechanical ventilation a necessity.