The Best Eco-Friendly Barn Insulation

These green insulation materials offer an alternative to fiberglass and foams made with petroleum products.

by Leslie J. Wyatt

The advantages of insulating barns and outbuilding are clear: lower heating costs; more comfortable working conditions; better overall animal health with accompanying increase in milk, egg, or meat production. These benefits apply to summer as well as winter temperatures. According to the Purdue University Extension Service, proper insulation is the most effective conservation measure. With current energy costs, an insulation investment with a 20- to 30-year useful life can pay for itself in two to three years, depending on the building’s present condition and intended use. In past years, fiberglass batts and polyurethane foam have been the go-to choices, but they aren’t very ecologically friendly due to their materials and the amount of energy it takes to produce them. Here are three greener options to make your barn more livable and energy friendly.

1. Cellulose Insulation

Arguably one of the greenest of insulating materials, cellulose is made from up to 85 percent recycled newsprint and other paper waste, plus a few non-hazardous chemicals (borates and ammonium sulfates) as fire and pest retardants. Not only does manufactured cellulose insulation prevent all that paper from ending up in landfills and releasing greenhouse gases during decomposition, pollution from its manufacture is negligible. Cellulose insulation also has a very low “embodied energy,” the amount of energy it takes to make the product—much lower than fiberglass or other less green options. With an R-value of 3.6 to 4.0 per inch of depth, it rivals the conventional fiberglass insulation (3.0 to 4.0). Price per square foot is comparable to fiberglass.

Unlike fiberglass, cellulose has a natural insulating capacity, and when densely packed it prevents air circulation, hence heat loss. In contrast, compressed fiberglass loses insulating value, and as anyone who has installed it knows, compression is very difficult to avoid when installing fiberglass in batt form. Yet one more advantage for this green option—insulating with cellulose reduces the carbon footprint, as it ties up carbon content for the life of your barn.

Cellulose insulation is not without its downsides, though. When damp, the borates (non-poisonous unless ingested) can be somewhat corrosive to metal and brick, so if you have a metal pole barn, which tends to sweat, you’ll probably want to steer clear of cellulose as an insulator. A moisture barrier is often a good idea after the cellulose has dried, but bear in mind that moisture can come from more than just the inside of the building. Wet cellulose can be a problem, especially if you get a plumbing or a roof leak, because it can absorb a whole lot of moisture before you know you’ve got a problem. Thankfully, leaky plumbing probably isn’t too much of an issue in barns, but some barns/outbuildings can be less than waterproof during driving rain or with snow banked up again them for weeks on end.


Cellulose insulation is blown in with a special blower as a wall spray and can be applied before sheathing in new construction or through holes drilled in the existing walls. If applied to roofs or ceilings, some sort of sheathing or net is required to keep it in place once it has dried. For new construction, after installation, you’ll want to cover walls with sheathing, such as plywood, so animals don’t peck, paw or nibble it out.

Installation Pros:

  • Virtually no waste on the jobsite—no leftover bits of batts or foam panels in the dumpster headed to an eternity in a landfill. The special machines used to apply cellulose insulation allow the installer to vacuum up and re-use or salvage excess or over-sprayed material.
  • DIYers can install loose-fill cellulose insulation themselves (more applicable to floors than walls).

Installation Cons:

  • Fibers can be irritating to some installers.
  • Can settle if blown in dry, thus leaving uninsulated spaces.
  • Does not lend itself to DIY projects.

2. Cotton Insulators

Another eco-friendly option, cotton insulation is also a recycled product. Made of cotton and polyester mill scraps (lots of denim in the mix), cotton insulation has no effect on air quality, pollution during manufacturing is negligible, and again, carbon footprint is small and landfills are saved the added burden of holding the multiplied tons of recycled material. As in the manufacture of cellulose insulation, the embodied energy factor is low, making it an even greener alternative than fiberglass, mineral wool or other insulations. R-value is right up there with cellulose and fiberglass—R-3.5 to R-3.7 per inch.

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Like cellulose insulation, cotton insulation is processed with borates. Plus, mice hate it, it’s fire resistant and it’s not prone to mold. In fact, it’s as hazard-free to handle as your favorite blue jeans. As insulation against noise, it beats fiberglass, as well.

Unfortunately, cotton insulation is higher priced than fiberglass or cellulose, (15 to 20 percent higher than fiberglass, though still cheaper than some insulation alternatives), and some compaction may happen during shipping, which can reduce R-value (though companies claim a bit of time out of the packing bag will restore the “loft”). As with cellulose, borates make it a better choice for wood structures, as cotton absorbs water. Although eco-friendly in its use of recycled material and embodied energy quotient, cotton itself takes a lot of water and fertilizer, and people are concerned that a growing demand for this “green” insulation may prompt growers to turn to further chemical means of obtaining top crop yields, and increase water usage.


Cotton insulation comes in batts, making it possible to install yourself if you want to save labor costs. Manufacturers suggest using a semi-permeable vapor barrier over the batts. As with most insulating material, walls should be sheathed after installing cotton insulation to keep your animals from pulling it out from where you have so painstakingly placed it.

Installation Pros:

  • One great beauty of cotton insulation is that unlike fiberglass, it does not
  • Can be installed without special equipment or even gloves.
  • Does not contain toxic chemicals.
  • Requires open walls to install.
  • Contrary to advertising, cutting the unfaced batts isn’t as easy as they make it sound.
  • Batts are a bit wider than standard framing in order to “friction fit,” but somehow they don’t compress as easily as fiberglass, and the result may create cold spots.

3. Soy Foam

Foam insulation has been an industry revolution, offering benefits other types just cannot give. It kills mold on contact and inhibits future mold growth. Insects can’t eat it, it’s not damaged by water and it doesn’t settle or compress over time, thus it does not age or split. It expands upon application, creating an airtight layer. In addition, foam insulation prevents air leakage and is adaptable to both small and large areas. It’s also good for wall cavities and ceilings, has great sound-reduction properties, and over the life of the building, foams will save more energy per inch than other types of insulation. All this translates into 20- to 40-percent better overall performance than fiberglass or cellulose.

Cool stuff, but it has some drawbacks, and one of those is that until recently, foam insulation has been available only as a petroleum-based product. Nothing eco-friendly about that, which is why the advent of soy-based foam has gladdened the hearts of green-conscious owners who would love to go with foam for their barn insulation. Soy foam is a low-density product with an average R-value of 3.5 per inch in which approximately 40 percent of the ingredients come from that wonder plant, the soybean. That’s good ecological news.

Unfortunately, though manufacturers are working to perfect green alternatives, soy foam still includes quite a lot of chemicals, and though greener than its foamy alternatives, its embodied energy factor is quite high. Furthermore, foam does not prevent radiant heat transfer, and without a radiant barrier your barn will be hotter in summer and colder in winter than with other types of insulation.


Foam lends itself to both new construction where wall cavities are exposed and to retro-insulating through holes drilled in the top of the walls, ceilings and roofs. In areas where animals can chew on it, foam insulation will need to be covered up, as they will peck or pull it out of the cavities and leave you with gaps in your airtight layer.

Installation Pros:

  • Although professionals and their specialized machines are often called on to do the job, DIY kits are available through suppliers.
  • Foam insulation can be applied to exposed cavities or sprayed into the cavities through holes drilled near the top.
  • As it expands, the foam fills cracks and crevices other insulations can’t reach, and not only prevents heat loss, but can also lend structural strength to walls.

Installation Cons:

  • Low density/open cell soy foams might need a separate vapor barrier.
  • Professional application may be needed to give best results in some cases.

In a world that is increasingly aware of the need for eco-friendly choices, insulation made of cellulose, cotton or plant-based oils can be viable green alternatives for your barn or outbuildings. Manufacturers will have specs and installation directions to assure that your barn gets the insulation it needs and deserves. Here’s to great green solutions to the age-old question of how to keep your animal and yourself warmer or cooler as the seasons change.

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