What is Hemp Insulation? (And How it Compares to Standard Types)

When you decide to install insulation in your home, you need to research all available products, shop around for a legit company, and purchase the best one. 

If you are looking for more cash in your pocket, insulation is the one investment that provides guaranteed returns. It doesn’t just help you cut down on your energy bills—it also significantly increases your home’s value. 

Hemp insulation is a type of insulation that’s rapidly gaining popularity. This article will discuss everything you need to know about hemp insulation, including what it is and how it compares to better-known types. 

What is Hemp Insulation?

Hemp insulation is manufactured using hemp wool. Hemp wool is made with wood and strong fibers obtained from a hemp plant. Hemp insulation contains approximately 92 percent hemp and around eight percent polyester fibers. Fire treatment and non-toxic bonding agents constitute the remaining composite.

Hemp insulation can also be intertwined with polyester, flax, or kenaf fibers that help act as a binder. Hemp insulation is typically bought in batts. These batts are made from the inner fibrous layer of the hemp plant and are 3.5 to 5.5 inches in thickness. 

Hemp insulation is considered a substitute for foam and fiberglass—it’s an alternative that has a considerably lesser effect on the environment during the manufacturing process. In addition, as hemp is a plant product, hemp insulation provides organic benefits when used.

Hemp Insulation – Ecological Advantages

America has been manufacturing hemp insulation since around 2018. Thus, it is considered relatively new to the market. Nevertheless, there are legit reasons to think that hemp insulation can surpass fiberglass and take its place as the industry leader. 

Hemp isn’t just a plant; it is also considered a cover- or break-crop, meaning that it is planted to enhance soil health by suppressing weed growth, minimizing the dependency on herbicides.

Hemp’s nutritional requirements are different from wheat’s, which helps to enhance overall soil structure by adding potassium and nitrates. 

Its long taproot grows deep into the soil and loosens up compressed soil, offering a much better water table. In addition, it grows pretty quickly and doesn’t require plenty of room to produce either.

Keep in mind that a single acre of hemp can produce seven hundred pounds of grain. Furthermore, it has a turnaround time of as little as seventy days, from planting to harvesting. 

Hemp is a crop, which makes it a renewable and sustainable product. It can easily grow in diverse conditions as it needs only minimal water levels. Plus, it doesn’t depend on artificial irrigation, meaning hemp can grow fully without any herbicides or chemical pesticides. 

Exposure to herbicides and pesticides adds to the number of pollutants and toxins in the water and air. Therefore, reducing usage helps combat several health and environmental issues. 

Little energy is used in the production process, further reducing the environmental impact. On average, hemp insulation needs 14 times less power to produce than the polyurethane that offers a similar level of thermal performance.

It’s the perfect material for “zero-carbon” homes as it absorbs more carbon than it uses during construction. Moreover, once hemp insulation has reached the end of its life, it can be recycled or used as compost because it’s an organic product. 

Performance of Hemp Insulation 

Certain household products, like bamboo floors, are incredibly eco-friendly. However, they scratch quite easily and have a fairly short lifespan. Conversely, hemp does fairly well in terms of performance.

The most significant advantage of hemp insulation is its reaction to moisture. Hemp fibers are pretty breathable, allowing vapor to travel through the insulation, which is a positive.

The hemp works as a condensation filter, gradually dissipating the moisture as it moves through the product. Moreover, hemp is hygroscopic, meaning it can absorb condensation to control the humidity level inside your house.

Hemp insulation is highly impervious to moisture. In fact, it can possibly be removed, dried, and replaced in case a wall experiences any kind of water damage.

Hemp is very similar to a sponge or towel when it comes to water exposure. On the other hand, fiberglass is comparable to a cotton ball that will break apart when wet. 

In addition, hemp insulation is quite dense. The average thickness is 3.5 to 5.5 inches; however, it is also available in thickness of 7.5 inches. Thicker hemp insulation enhances its acoustic absorption properties.

It is available in 4 inch long batts that will stay strong when stood up between wall studs. Blown-in insulation or rolled fiberglass will compress or slump over time. 

Hemp Insulation – R-Value

The primary benefit homeowners want from insulation is the prevention of air entering and escaping their homes through the walls. The terms used to describe the insulation’s performance are R and U-value. 

R-value denotes the insulation’s thermal resistance. The larger this figure, the better your insulation will prevent cold air and heat loss. Hemp insulation is usually rated at an R-value of 3.5 per inch.

Hemp’s compression ability is where its installation becomes a benefit. For example, you can install a piece of hemp insulation between 3.5 inches studs to obtain an R-value of 19.25, which is significantly higher than what’s needed by even the coldest regions in North America. 

Another interesting thing to note is that other types of insulation generally lose their R-value over time. However, hemp’s R-value stays at 3.5 throughout its entire lifespan while also enhancing the wall assembly’s resilience to moisture damage.

U-value indicates heat transfer. Unlike R-value, the smaller this figure, the better. Again, hemp insulation has a fantastic U-value of 0.039, nearly equivalent to 8-inches of fiberglass insulation used in walls.

Uses of Hemp Insulation 

You can use hemp insulation in several parts of your home, including ceilings, attics, and inner and exterior walls. In addition, thanks to its higher density, you can use it as external wall insulation before siding insulation. 

Remember that hemp insulation isn’t a load-bearing product, so use it with caution for floor insulation applications. Its vapor permeability plays a major role in its wide range of uses in wall assemblies and adaptability to all kinds of environments. 

Thickness of Hemp Insulation 

You can install hemp insulation in any thickness you want. The batts are available in standard sizes to fit 2×6 and 2×4 wall cavities for 24 or 16-inch stud centers. Typically available thicknesses include 8, 5.5, and 3.5 inches. You can stack these on each other if you wish to go even thicker. 

How Does Hemp Insulation Compare to More Standard Types?

In this section, we will see how hemp insulation compares with other types of insulation. 

Fiberglass Batt Vs. Hemp Insulation 

There are essentially four kinds of insulation that hemp has to compete against in the industry. These include blown/loose-fill, foam board, spray, and batts.

Hemp insulation can be viewed as part foam board and part batt. This versatility provides hemp an advantage right from the start. 

The most widely used material is fiberglass or mineral wool for batt insulation. The R-value of fiberglass lies between 2.9 and 3.8. 

However, both hemp and fiberglass have fairly similar production when it comes to heat flow resistance. 

Nevertheless, the u-value of fiberglass is only 0.05 per six inches. A regular fiberglass batt is around 3.5 inches thick. Thus, it will take approximately 8 inches of fiberglass batt to match the u-value of hemp. 

Another thing to keep in mind about fiberglass batts is that they suck up moisture without it penetrating. Fiberglass material tends to suck up the condensation and then just allows it to sit there, resulting in mildew and mold growth. Thus, you will also have to install a vapor barrier on unprotected fiberglass batts. 

Hemp’s most prominent benefit over fiberglass batts is on the environmental-friendliness front. Tiny pieces of glass make up a considerable portion of fiberglass insulation.

Other bonding agents are limestone, silica sand, borax, soda ash, feldspar, aluminum, etc. These products aren’t just hazardous, but they can even increase the amount of energy used in the manufacturing process. 

Rigid Foam Board Vs. Hemp Insulation 

Foam board is another popular insulation product. Styrofoam, or expanded polystyrene, has an R-value of 3.6 to 6+ per inch.

As foam is stiff, it remains in place. Nevertheless, it also means it is more difficult to work around pipes, wires, and outlets, which can result in a significant loss of heated or cooled air. 

Rigid foam board offers the best moisture-resistant properties. In fact, some products even have reflective foil installed to further prevent heat absorption.

Again, the environmental effect of producing foam is much more destructive than hemp. Foam contains chlorofluorocarbons, which lead to global warming and ozone depletion. Certain kinds of foam insulation, like phenolic, are no longer produced because of the environmental damage they cause. 

Other Types of Insulation Vs. Hemp Insulation 

Two other popular insulation categories include spray and loose-fill. Spray foam creates the tightest insulation, given that it is installed correctly.

The R-value of open-cell spray foam is 3.7 per inch, whereas the R-value of closed-cell can be as much as 6.5 per inch. However, houses that are sealed too tightly can allow carbon monoxide and nitrogen dioxide to build up and result in moisture accumulation. 

Loose-fill insulation is still comprised of tiny foam particles and fiber, among other dangerous things that can be inhaled during installation. Cellulose offers the most effortless installation when there isn’t access to the studs. Cellulose R-value ranges between 3.2 to 3.8 per inch. However, that reduces as fibers compact and sag over the years. 

Hemp Insulation Costs 

Fiberglass batts are priced between $0.64 to $1.19 per square foot, whereas 3 ½ inches batts of hemp cost nearly $1.80. In fact, the thicker 5.5-inch pieces of material are approximately $2.40. 

The cost of a rigid foam board lies between $1.41 and $2.48 per square foot to install. However, that is just the 1-inch thick material. Open-cell spray foam costs around $0.44 to $0.66 per board foot, and closed-cell spray foam costs around $1 to $1.50 per board foot. 

In short, hemp lies somewhere between the price range of these other popular insulation types. 

Top Hemp Insulation Brands

Here is a list of the top brands providing hemp insulation. 

1. Hempitecture – A firm based in Ketchum, Idaho, provides good-quality hemp batts. 
2. MEM Inc. – Located in Montreal, Canada, MEM Inc. is one of the first firms in North America to manufacture hemp insulation commercially. 
3. Nature Fibres – Based in Quebec, Canada, Nature Fibres provides batt insulation. The company is a success story of a sustainable product that replaced the harmful production that the town once depended on. 

Ideally, you should source your hemp insulation from the nearest manufacturer to minimize transportation costs and energy footprint. 

Drawbacks of Hemp Insulation 

Perhaps, the biggest con of hemp insulation is its current lack of availability. It is not widely available locally across North America. Consequently, you might have to pay a higher price to acquire it than other forms of insulation. 

Nevertheless, an increasing number of states are starting to step forward in easing regulations related to hemp farming. Hopefully, this will encourage more entrepreneurs to see the value in using hemp as a practical crop for insulation purposes and other building processes like hempcrete – a combination of sand, limestone, plant fibers, and other composites.

Last Few Words

Hemp insulation competes strongly with its alternatives in overall long-term performance. However, it stays at number one when it comes to sustainability. It’s only a matter of time before this insulation becomes widely available throughout North America.