by Ali Lawrence, a kombucha tea-sipping writer who focuses on healthy and sustainable living via her family blog Homey Improvements

Not all insulation is created equal. Some insulation might get an A for fire prevention, but receive Fs in health and safety thanks to its chemical components. Others may be easy on your energy bill but hard on the environment.

Over the years, great strides have been made in terms of green insulation. Today, homeowners have several effective, safe, eco-friendly options available to choose from when building or retrofitting their homes. Whether your concern is for your health and safety, the environment or your energy bill, the following five insulators provide the exceptional, safe performance that has come to be expected from green building materials.


Recycled materials can make for excellent insulation. Take cellulose, for example. Cellulose is 85 percent recycled newspaper and 15 percent borate fire retardant.

Think fire retardant always means dangerous chemicals? Think again. Borates are mineral compounds that are not only environmentally safe but also prevent pests and molds in addition to fires.

Cellulose provides a great use for recycled newspapers, is a safe way to insulate your home and costs roughly the same as popular fiberglass options while still beating them for value.


Does the thought of wasted denim keep you up at night? No need to fret; plenty of scrap denim and old jeans are turned into cotton batting and used as insulation.

Cotton insulation absorbs moisture, repels insects and is formaldehyde free. When treated with a little boric acid, cotton insulation becomes flame retardant.

The only downside is that cotton insulation is more expensive than other options. Depending on your recommended insulation levels, it may not be the most cost-effective option.

Wood foam

Wood foam is made from grinding wood into microscopic particles that then undergo a process to turn them into hardened foam.

Wood foam can be used for wall, ceiling or floor insulation. It doesn’t shed, won’t settle and can retain its efficiency and effectiveness longer than other insulation options.

Universities are currently investigating the possibilities of creating wood foam from recycled wood and wood waste. This would make wood foam an even greener option, as it would not have to rely solely on harvested trees.

Sheep’s wool

What better way to insulate your home than with a renewable resource that is designed—and proven—to retain heat in even the coldest, dampest climates?

Sheep’s wool can have an R-value—a unit of thermal resistance—of up to four, but that isn’t the only selling point for this natural insulation. Wool’s breathability means that it can take on moisture without sacrificing heat retention. Wool can actually take on a fair amount of moisture without becoming damp. The moisture retention even helps the wool produce heat, thereby preventing condensation.

What’s more, wool won’t clump, it won’t settle and it’s completely safe to work with.


When you think of insulation materials, castor oil is probably not your first thought. However, if you have the money to afford it, it should be.

Castor oil is the base of the spray-in foam insulation known as Icynene. Icynene is one of the most effective—though expensive—insulations on the market today. Not only is it a green option, it’s also the most effective at sealing air leaks. It’s so effective, in fact, that you may need to install ventilation to prevent the home from overheating. Although it traps air, it still allows water vapor to escape, which prohibits mold formation.

Icynene is sprayed on in a thin layer that expands to 100 times its volume. That thin application is enough to reduce a home’s energy bill by 30 to 50 percent.

Read more on this topic in Energy Loss in Homes and the Benefits of Insulation [infographic]>>