Hemp Insulation: How Does It Work?

 A person wearing a blue uniform and an orange glove holds a chunk of pink insulation in an unfinished wall.

Grab your hard hats, kids, we’re getting down to some serious business today! We know all about hemp on an intimate level (hemp undies for life woo!,) but this magic little plant has other powerful capabilities. This includes use in some heavy-duty construction settings. It can take many forms including hemp insulation, our golden ticket item for the day. 

If you’re already sold on hemp underwear, you’ll be delighted to know that there are many more hemp products available out in the world. This includes the standard stuff from skincare, clothing, and dietary supplements to larger-scale innovations like hemp plastic. Hemp is one of the most versatile leaders in the revolution for a greener world. 

My enthusiasm for hemp’s shapeshifting abilities aside, we’re here to talk about a specific iteration of hemp. Hemp insulation. What is hemp wool insulation? How is it made? Why is it the most eco-friendly option for insulating your home? Oh, I’ve got all those answers for you (and more) so hang tight and let’s get right into it!


A person’s hand holding up a hemp leaf against a dark background.

First off, what the heck is insulation, anyway? Well, insulation essentially serves to regulate the temperature in your house. It works by installing a material of choice (there are many different types of insulation) into the walls to block the natural heat flow. This means that whatever cooling or heating you’ve got going on inside will remain within your home and the outside temperatures won’t penetrate the walls and enter your house.

Now, more minutely, what is hemp insulation? It is a composite material made up of 92% hemp fiber and 8% synthetic binding material. It comes in thick, coarse batts or boards ready to be installed in your home. It is a highly breathable and durable insulation material.

Hemp insulation is often compared to fiberglass insulation, one of the most popular insulation materials on the market. Both have a similar capacity to retain heat, although hemp insulation has a few extra special qualities, including positive ecological impact (and more, we’ll get there)!

I know we’re all staring at the picture of the hemp leaf with our mouths agape saying “huh?” How does a little leaf turn into thick, durable padding that helps retain the heat in your home? You’ll find out in just a second!


green hemp field under blue sky

So, how is hemp insulation made? By using something called hemp wool (see: hemp vs wool) which is made using the fibers inside the stalk of a hemp plant. This part of the plant is also known as hemp hurds. Hemp hurds were once considered a by-product while the rest of the hemp plant has many commercial uses. Now, however, there’s a rising interest in this tougher part of the hemp plant. It has many applications in the field of construction. 

The hemp hurds are pressed into blocks and mixed with a lime-based binding agent. This forms the “batts” that are ready to be installed in your home. These hemp insulation batts are a lot easier to handle than traditional insulation materials because they are safe to touch with bare hands. They also don’t contain any particles that could be harmful to breathe. 

Although hemp insulation is not yet the industry standard, it is on the rise. One study cites that 25.9% of the hemp fibers produced in Europe were used as insulation material. This is great news because the production process of inorganic-synthetic insulation materials has a much worse environmental impact.

Why is hemp insulation superior to other options on the market? Oh, many, many reasons! I’ll share them all with you right now.


Modern stucco hemp house at end of driveway on edge of cliff.
  1. Hemp Insulation Is Safe And Natural: Hemp insulation is completely natural and safe to the point that it can even be handled without gloves. Other insulation materials can irritate or cut your skin. It has no scent and is completely non-toxic so it will not impact the air quality in your home negatively. 
  2. Hemp Insulation Works Well In All Seasons: Hemp insulation has an R-level of 3.5 per inch of material. This is pretty much the standard in the industry which means it performs just as well as fiberglass in terms of thermal retainment.
  3. Hemp Insulation Helps Regulate Humidity: A quality unique to hemp insulation its ability to trap moisture. This can help lower the humidity in your home, in addition to preventing mold growth.


 white gloved hands hold up a small globe with a plant growing out the top
  1. Hemp Insulation Is Biodegradable: That’s right, once you remove the insulation from your walls (for whatever reason) it can simply be composted, as opposed to other types of insulation. 
  2. Hemp Improves The Soil It Grows In: Hemp is a fairly low maintenance plant that can grow in a variety of conditions. On top of that, it makes the soil it grows in healthier, reducing the need for synthetic pesticides. 
  3. Hemp Grows Quickly With Minimal Water: One of the main draws of growing hemp in large quantities is that it needs very little water to grow. 
  4. Hemp Insulation Is Pest-Resistant: This is both a personal benefit as much as an ecological one. Hemp insulation helps keep your home insect and rodent free. Other insulation materials are susceptible to housing termites and fungus, both of which can be destructive to your home’s structural stability.


An empty room with unfinished walls, a broom and a bucket propped against a wall and a blue tarp hanging above a window

Now that we’re all on the same page about what hemp insulation is (and why it’s awesome) we’ll look at how it measures up against the traditional choices on the market. Before we can do that, we need to do a quick rundown of the systems used to grade insulation materials. 

There are a lot of factors to consider when choosing a material for insulation. Climate, the type of heating/cooling system you have, the location for the insulation, as well as the type of home you’re planning to insulate, are all things you’ll need to keep in mind. 

The effectiveness of insulation material is graded using a system called R-values. This value determines the material’s thermal resistance. The greater the R-value the more effective the insulating capabilities of the material.  

Doubling up on an insulation material will also increase the R-value. However, installing too much of it, or putting the material in a tight space will compress it, thus affecting the R-value. It’s a delicate system!


An empty room with unfinished walls, a broom and a bucket propped against a wall and a blue tarp hanging above a window

Fiberglass is the most common insulation material available. It comes in batts that have an R-value ranging from 2.9 to 3.8. In terms of heat retainment, fiberglass and hemp are pretty well matched. 

Where hemp comes out on top (in terms of functionality), is in its ability to trap and release moisture. Fiberglass is prone to mildew and mold growth because it absorbs moisture, without the ability to release it. 

Of course, the biggest advantage hemp has over fiberglass is the environmental impact. Fiberglass is usually made of blown shards of glass and synthetic binding agents that take a lot of energy to manufacture. This also makes fiberglass a health hazard; it can damage your lungs when inhaled. 


 Bits of newspaper and recycled paper make up cellulose insulation.

Cellulose is currently the most popular “green” choice when it comes to insulation because it is made up of at least 80% recycled newsprint and other paper materials. It’s mixed with borate and sometimes ammonium sulfate for binding and fire and insect resistance. 

This is a loose-fill type of insulation so it gets poured directly into the walls or attic spaces. Cellulose insulation is not suitable for basements or areas that are exposed to a lot of moisture.

It is also prone to sagging and deterioration of its R-value over the years. Hemp insulation is much more durable and can also be used in any area of your home. 


Man in white tee installs insulation into wooden frame of a house.

Mineral wool insulation is comparable to fiberglass insulation because they’re made using a similar process, just different materials. Fiberglass insulation is made of blown glass shards whereas mineral wool is made from blown rock. 

Mineral wool insulation is considered superior to fiberglass because it holds its shape better, making it easier to install and has a higher R-value. It is, however, more difficult to cut. 

The biggest downside to mineral wool is the negative environmental impact. The process of melting down the rock shards to make mineral wool requires a lot of energy. In fact, mineral wool products rank highest for stratospheric ozone layer depletion potential

Tall green hemp plants grow towards the sky at sunset in field.


Polystyrene (and other materials) can be used to make rigid foam boards for insulation. These boards are a lot less malleable than the insulation materials that come in batts which makes them more difficult to install. 

These rigid foam boards can have R-values ranging from 3.6 to 6 so they are very effective at retaining heat. Their rigidity, however, can lead to gaps around pipes and wires which make it less effective. 

Like hemp, polystyrene also has a high capacity for resisting moisture. It is, however, prone to aging or thermal drift (which is a phenomenon during which the gas in the foam boards is replaced by air). Another downside is the environmental impact of producing polystyrene, which contributes to ozone layer depletion and global warming.


A person holds on to a wood plank while another person stamps down concrete with a tool.

The qualities that make hemp stronger than steel in an altered state are what make this plant such a good resource for various building materials, like hemp insulation. Developers are turning to hemp as a sustainable material for other construction products too! Here are a few examples:


Hempcrete is made using only hemp hurds (just like hemp insulation), a lime-based binding agent, and water. The result of this mixture is hemp concrete, aka hempcrete! Hempcrete is much lighter than traditional cement and therefore has slightly different capabilities.  Hempcrete can be used in flooring and to build walls that don’t have to bear any weight. 

And guess what? Using hempcrete in your home not only provides some structural support but also acts as insulation! Two birds, one stone made of hemp. 


hand holds three different color wood boards against river and mountain vista.

This one is for the trees because they deserve to be hugged, not cut down. That’s where HempWood comes to the rescue. It is a wood alternative designed specifically to mimic the properties of oak. It can be used for interior building, flooring, and furniture.

Not only is hemp wood completely environmentally friendly to produce, but it’s also super durable! Knowing what hemp is capable of, this comes as no surprise. The only downside I could find is that HempWood is not very widely used at the moment. Hello! We need to fix that. Save our darn forests and embrace hemp!


While it’s not entirely a “construction” product, hemp rope is a necessary mention when talking about the practical uses of hemp. In fact, hemp rope can be traced back as far as 29,000 years ago. It was used for sailing, and making fishing nets, and I’m willing to bet it was involved in some ancient-day construction projects.

Thanks to hemp’s natural strength, hemp rope is the perfect product for lifting, rigging, or pulling anything heavy. If you ask me, that sounds like a useful tool to have around during any building project!


 A man wearing a green shirt and a blue hat cuts a wire in a space full of wooden beams and white fluff on the floor.

Well, now that we all know what hemp insulation is, I hope the intrigue is building. If you’re still a little confused and unsure, don’t worry, I’ve got your back. Here are some frequently asked questions regarding hemp insulation:


As someone who is most certainly not a handyman my instinct is to say “by hiring a professional.” If you know what you’re doing, then hemp insulation is not any more complicated to install than traditional insulation. In fact, it requires less protective gear than fiberglass insulation!


Hemp wool has excellent resistance to mold because it is able to retain and release moisture without any detriment to its insulation abilities (although nothing is completely mold-proof when exposed to large amounts of water). It even helps protect other structural components by trapping airborne moisture.


Nope! You already trust your hemp bikini underwear or trunks underwear to interact with your most intimate parts, and that’s enough to know that all things hemp-made are safe and natural. 


At the moment, yes. There aren’t many manufacturers producing hemp insulation and it’s yet to become a widely used product. This makes the distribution a little more costly. 


Wooden house in construction in a field scattered with finished houses and trees.

I could spend all day spitting facts about hemp (and often I do) but the main point is that hemp is a key player in the push for a more environmentally conscious world. I hope you’ll strongly consider hemp insulation for your home!

Do you already have experience with hemp insulation? If so, tell us about it in the comments! The more excitement we can raise around products like hemp insulation, the likelier they are to become the industry standard!

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