﻿Insulation is the most important building feature for comfort and energy efficiency. Unfortunately,
common mineral wool insulation like fiberglass, Rockwool and slag wool that are used in almost
every home are energy intensive products with very high carbon footprints. A company in Idaho called
Hempitecture has come up with an alternative building insulation that is eco-friendly and
has a low carbon footprint. HempWool is a plant-based,
sustainable and high-performance insulation for walls, floors and ceilings. It provides
resistance to the flow of heat and lowers your heating and cooling costs. It is quickly gaining
traction in the construction industry, as a replacement for traditional insulation.
I recently visited the factory in Idaho to learn more about the company and their products. In this
video, we’re going to discover how Hemp Wool is made, how it performs and its pros and cons.
HempWool is a natural thermal insulation made from the fibers of the hemp plant. Bales of shredded
hemp arrive at the manufacturing facility from all over Northern States and Canada. The color of the
dried hemp fibers varies depending the amount that it is retted. Retting is a process that allows
moisture to begin separation of the fiber from the stalk. Darker fiber has been retted for longer,
and lighter fiber has been retted for less time. HempWool can also include sheep wool
from New Zealand or recycled wool. Hempitecture’s acoustic insulation batts use recycled and virgin
cotton for better sound absorption. To bind and fuse the hemp fibers together, they use a small
amount of polyester bonding fibers. Some people may not like the fact that
Hempitecture uses plastic in a natural insulation product, but I personally
don’t see it as a problem. Plastic is such an incredible and versatile human invention. I’ve
said this before in previous videos; short-term and one time use plastic is wreaking havoc on
our planet. Long-term use plastic can actually be more sustainable than metal or glass. High quality
insulation like HempWool can last a hundred years. Hempitecture also tries to use recycled polyester
fibers in their insulation to further lower the energy footprint of their product.
Dashawn Hutchinson, production manager at Hempitecture walked us through the HempWool
manufacturing line and explained how every machine works. The first machines used are bale openers.
Tightly compressed bales of hemp, polyester, cotton or other ingredients are lifted onto
these machines. They comb, stretch and break up the fibers and then transport them to the
next step of the production line. The quantity of the raw ingredients pulled through depends
on the moisture content of the hemp fibers. The bale openers can be fine tuned through these
manual controls. You can specify the percentages of each material, air pressure, quantities,
see what’s jammed and more. The second machine is a pre-opener. Small metal spikes on a wooden
drum grab the hemp and polyester fibers, separate them and pull them upwards through ducts.
Conveyor belts, motors, fans and air move the fibers to the third machine,
a blending box. The fibers are dropped in layers so you can see the white polyester
bonding fibers mixed in with the brown hemp fibers. The typical mix for indoor
insulation is 92% hemp and 8% polyester. Rigid boards for exterior insulation need
more polyester fibers to make it stiffer. This part of the machine also has a self-cleaning
cylinder, a fluffer, a separating drum and a packer. You can specify how much fiber can
be packed and sent to the next machine. This fourth section is called the fine
opener. Another wooden drum with metal spikes slowly opens the fibers one last time before
sending it upwards to the next part. The fifth and most important machine is the
airlay. An air pressure regulator pulls fibers, packs them together and deposits
them on a moving belt. When the pressure drops, it pulls more fiber. When the pressure gets too high,
the fiber drops down. This method creates a finely mixed uniform web of fibers with the
desired density and thickness. Deshawn, who was giving us the tour,
referred to the airlay machine as the holy grail of the production line. It is critical
to get the right thickness, density, consistency and proportion of raw materials in this machine.
Fortunately, if the mix isn’t right, they can salvage it and throw it back into the start
of line, which are the bale openers. The sixth and final part of the production
line is the oven. The HempWool insulation is gradually pressed down as it passes through 3
stages of heat. For a typical insulation batt, it goes from 7” to 6.5” to the final 5.5”. The
machine uses natural gas burners and fans to heat the fiber mixture up to 150 degrees Celsius
or 300 degrees Fahrenheit. After the polyester fibers melt
and fuse the hemp fibers together, the hemp wool batts are cooled down with exhaust fans and moved
to the cutting station. Large circular blades that look like pizza cutters cut the insulation batts
down to 16” or 24” widths. A guillotine blade cuts the batts to the final length, usually 48”.
I made a video on HempWool insulation a couple of years ago. Hemp is a sustainable, fast-growing
product and I love seeing its resurgence in popularity after decades of suppression. I also
love the idea of using hemp as an eco-friendly building material. Hempitecture has made a lot
of progress in the last couple of years. They used to only sell HempWool from other companies,
but now thanks to their manufacturing facility in Idaho, they can produce their own product. Touring
their plant made me appreciate how much hard work goes into producing this insulation material. Hemp
is a tough fiber to manipulate and Hempitecture is the only company in the US making this material.
They don’t have a playbook to follow, so they are learning through continuous experimentation.
Right now, they are scaling up production of 4 insulation batts. The thinnest ones are 2”
and 3.5” that fits into a standard 2x4 stud bay. They also have a larger 5.5”
thick batt that fits into a 2x6 stud bay. The third product is a massive 7.5” thick
batt that fits into 2x8 studs bays. All these batts have an R value of 3.7 per inch. (*they
are working to prove this result under American testing parameters). So, this particular product
would be great for an exterior R30 wall. Hempitecture is also conscious of their energy
consumption. While they use natural gas in their burners, the rest of the plant
is powered with renewable energy. They have an advanced waste collection
system to ensure that nothing useful heads to landfills. Any scrap material is chopped
up and sent back to the production line. Hemp dust particles are also collected in large
drums. The production process of HempWool is very messy, so this system helps reduce
the particles released into the air. Fans pull any loose fibers and dust through
overhead ducts. They are filtered through a large mesh and collected for future use as pellets,
biomass or even compressed wood boards. Hempitecture is experimenting with other
types of HempWool products like thin underlayment for carpets. This flexible
material could be used instead of rubber, wool, foam or any other synthetic fibers.
They have also made an exterior rigid board panel that can be used as continuous exterior
insulation. This product is much stiffer, more waterproof and it’s fire rated.
In my last video on HempWool, I tested the fire resistance of the insulation and I was
very disappointed with the result. If you’ve watched the video, you know that the material
started smoking and the fire spread very rapidly. Thankfully, Hempitecture has now
addressed those concerns. They tested numerous fire resistance sprays and they found one that
works perfectly with their material. When exposed to a flame, the surface of the
material darkened, but it did not catch on fire. It didn’t even smolder. This is a huge
accomplishment from the previous iterations of the product. I was also impressed with its water
resistance. Water puddled on the surface for a while, before slowly sinking into the top layer
of the fibers. As you can see, the water did not seep through the entire insulation batt.
It was only absorbed by the top layer so the batt maintained its shape and structure.
I am very impressed with how far Hempitecture has come in the last few years. I truly admire
their hard work and entrepreneurial spirit. They are up against so many variables that are
out of their control, but they keep persevering. Dashawn explained this quite succinctly.
Every bale of hemp they receive is different. They are dealing with different plant species,
different moisture contents, different densities and more. Even the cooking times differ depending
on the species they receive. They cannot come up with a set formula for their product because
of all these variables, so every day presents a new challenge. But they are learning from
their mistakes and experiments and they just keep going. I was very inspired by their resilience.
Let me know what you think about HempWool in the comments and if you think it can revolutionize
the home construction industry. If you’d like to check out my podcast with Mattie,
the co-founder of Hempitecture, I’ll link it up here. Also check out my last video on HempWool if
you haven’t watched it yet. I’ll link my Patreon page in the description. I’m now offering early
access to ad-free videos on Patreon as a thank you to everyone supporting me. Don’t forget to hit the
like button, subscribe button and the notification bell too. Thanks for watching. See ya.