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Hemp insulation is made out of hemp wool which is, basically, the strong fibres of the plant mixed with cornmeal or polyester fibres.

Hemp insulation is a rapidly growing market due to the increased awareness of the toxicity of other insulations, and this new insulation might just be a game-changer.

Today, we are going to talk about the properties that make hemp wool an exceptional insulation material, starting from its durability and ending with the unexpected ecological benefits.

Here are the 7 reasons why hemp is a good insulator for your home.

  • Amazing Insulative Properties
  • Eco-Friendliness
  • Breathability
  • Waterproof
  • Fire-Resistant
  • Easy Installation
  • Durability

Amazing Insulative Properties

First things first, hemp wool is an incredible insulator with a high thermal mass and low conductivity.

The specific heat capacity of hemp is between 1800 and 2300 J / (kg * K). That of wood fibre, for example, doesn’t exceed 2100 and the insulation made out of sheep wool has a specific heat capacity of 1800.

So this would be my pick over both Sheeps Wool and Wood Fibre.

You can read more about these insulations here. 11 Types of Breathable Wall Insulation.

The R-value of hemp is 3.5 per every inch of thickness – that is pretty much the industry’s standard.

In a nutshell, if installed properly, hemp is going to keep the temperature in your house nice and comfortable throughout the whole year. Moreover, a hemp-insulated house can benefit from 50%-80% energy savings.

By the way, this material is also going to make your home quieter as it has great noise-insulating capabilities.

Bonus: Hemp insulation doesn’t have a scent.


Hemp is a fantastic source of raw material. The plant needs less than a hundred days to grow, is not seasonal, and can easily decompose without having a negative environmental impact.

The crop doesn’t consume a lot of water and a single acre of this plant can yield around 700 pounds of fibre.

Fun fact: hemp increases the health of the soil as it shades out weed and that, in its turn, reduces the need for various herbicides.

Relatively small amounts of energy are used during the production process. Moreover, buildings that have hemp in their structure can be referred to as ‘carbon negative’, because the material is able to lock in atmospheric carbon – 1 hectare of the plant absorbs 22 tons of CO2.

Breathability for Solid Walls

Hemp can actually regulate condensation as it allows the moisture to freely travel through the layer of insulation.

That’s exactly why a lot of people prefer to use hemp insulation in wood-framed structures – it will help avoid moisture build-up.

External and internal solid walls will also benefit from hemp insulation, as well as cavity walls, roofs, and floors (for both thermal and acoustic insulation).


The material is not only waterproof, but it will also not break apart after coming in contact with water. So, hemp is more like a towel in this sense, while fibreglass is a cotton ball.

In theory, if the insulation was to experience damage from a leak, it could be taken out, dried, and put back in. Hemp resists any slumping and is able to maintain its structure and form throughout its lifetime.


Nature-based materials are, in general, more flammable than chemical-based ones.

And yes, hemp insulation can chur, but it won’t burn, unlike a lot of other materials. The plant has high silica content which acts as protection against fire. This fact makes hemp wool one of the safest materials available for insulation out there.

The insulation can also be treated with various non-toxic flame retardants for extra protection.

Depending on the thickness of the insulation, it can remain fire-resistant for up to 3 hours.

Easy Installation

Of course, if you don’t feel comfortable installing home insulation on your own, you should hire a professional to take care of the job for you.

But, in any case, hemp insulation is one of the most pleasant types of insulation to work with.

Mainly, because hemp will not leave the contractor itching and coughing (the material is non-irritating on lungs and skin).

But also because the product comes in convenient boards (between 1 and 7.5 inches thick) or batts (4’ long) that can be easily cut and then closely connected which helps avoid any thermal bridges.

On average, the insulation is between 3.5’’ and 5.5’’ thick, but you can find thicker options if needed (up to 7.5’’).

The actual fitting method is not messy and quick. Moreover, when using hemp insulation, you can allow yourself to simplify the whole construction and use fewer materials and/or layers.

Finally, hemp insulation reduces the load on foundations as it’s a lightweight material.

Fact: hemp insulation is a little more expensive than a lot of other types, but it has a greater lifespan and impressive insulative properties which make it an eco-friendly (and smart) investment.


Hemp insulation is termite-resistant, impervious to moisture, and will not compress over the years. It is also resistant to bacteria, mould, and fungicides, so practically nothing is going to stop the material from serving long years.

Hint: for increased durability, exterior hemp walls can be finished with a breathable finish or natural render (lime or hemp-lime, for example). And that is all the protection hemp insulation is going to need.

To Sum Up

Hemp has quite a few cool properties that make it an excellent home insulator.

It can be easily installed, has outstanding insulative properties, is eco-friendly, breathable, waterproof, fire-resistant, extremely durable, and is multi-use (the insulation is suitable for ceilings, facades, walls, sloped roofs, wooden floors, and much more).

But, unfortunately, despite all these benefits, it is still relatively hard to find hemp insulation on the market. At the moment, growing and cultivating hemp is challenging (right now, a lot of suppliers are forced to import industrial hemp from abroad), so finding a reliable manufacturer who produces such insulation is quite the task.

However, the situation is going to change in the nearest future as the environmental advantages of hemp are going to take centre stage.

As a consequence, the cost of the material is going to significantly drop as the plant is going to be grown in the US and you don’t need a lot of land or time to produce plenty of hemp.

So, perhaps, this crop is the building material of the future.