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Hemp Insulation: A Carbon Negative Alternative To Rock Wool

By on July 16, 2013
Hemp insulation mats are usually made from 85% hemp and 15% polyester

Hemp insulation mats are usually made from 85% hemp and 15% polyester. They can also be treated with boron salts to protect from fires, mold and insects. – As industrial sectors start to take interest in sustainable materials, one plant has caught their attention. Hemp is now being considered as an eco-friendly alternative to concrete, fiberglass and, as it turns out, building insulation as well.

Besides the fact that hemp is one of the fastest growing industrial crops, it also makes a great thermal insulator. Insulation made from hemp fiber performs about the same as mineral fibers (i.e. rock wool) at trapping heat. But hemp’s real advantage over traditional materials comes from its environmental sustainability, as a group of Italian engineers recently found out.

Their findings, published last month in the Environmental Science & Technology journal, looked at the energy requirements and greenhouse gas emissions involved with making hemp insulation, including plowing and sowing, cutting and harvesting, fiber and core processing, and final production of the hemp panels.

The researchers evaluated every step involved with producing hemp insulation.

The researchers evaluated every step involved with producing hemp insulation.

The results show that insulation made from hemp requires far less energy than rock wool. While most of the energy input for hemp goes toward cultivating the plant, rock wool requires more energy in order to be melted, hardened and cured in a furnace.

Hemp also holds another advantage over rock wool after production, because of its ability to absorb greenhouse gases. In fact, the study showed a negative amount of CO2 emission from hemp, meaning that it absorbs more CO2 during its lifetime than it actually gives off during production.

Insulation mats made from hemp were found to give off a negative amount of CO2 equivalents (greenhouse gases)

Hemp insulation mats emit a negative amount of greenhouse gases (CO2 equivalents), making them an eco-friendly alternative to rock wool.

Naturally, the researchers concluded that hemp is the more eco-friendly choice for insulation:

“Indeed, the direct comparison between hemp-based and rock wool insulator mat shows the much higher sustainability of hemp.”

It’s also interesting to note that hemp panels are lighter than rock wool. In the study, they weighed in at 6.0 kg whereas rock wool mats measured 6.4 kg. Hemp is also good at insulating sound and reacts well when exposed to moisture, the researchers noted.

With all of these advantages, it’s not surprising to hear that some companies – such as UK-based STEICO – are already starting to offer hemp insulation for their more environmentally-conscious customers.

A woman installing STEICO's Canaflex brand of hemp insulation.

A woman installing STEICO’s Canaflex brand of hemp insulation panels.

  • AAron


  • Jerry Schull

    I’m wonder how long before Home Depot will be able to offer this?

  • Jeff Davis

    So is this R20ish? I have read it is about R-3.5 per inch of thickness.