Could this bio-based concrete made of hemp make our homes more energy efficient?
Darshan Dalal

It's not only the rising cost of energy that is demanding better and more sustainable use of our power resources. Scientists say achieving urgent climate goals now also needs a significant reduction in our energy consumption.

Domestic energy use in the UK has continued to rise despite soaring costs – and as households struggle to pay the bills, there are growing calls for more to be done to improve energy efficiency. 

Cutting down heat loss from buildings is vital and a UK-based company has come up with a new building material to do just that.

"Hempcrete, or hemp concrete, is a mixture of the chopped woody stalk of the industrial hemp plant with a building-lime binder," explains Alex Sparrow, CEO of UK Hempcrete. "You can think of hempcrete as a natural, renewable, better-than-zero-carbon walling and insulation material."

It is a bio-based heavyweight insulation material that traps heat within itself, unlike lightweight insulators. Sparrow believes this makes it a potential perennial solution for heating homes across the UK.

"Typically houses in the UK, from the south of the UK right up to the Orkney Islands, will sit there with no heating or cooling at 16 to 18 degrees Celsius all year round – and that's whether it's minus 10 or plus 30 outside," he says.


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Indeed, the UK has some of the world's oldest housing stock – and many buildings still lack basic modern insulation. No wonder a typical household in the UK with two to three residents consumes 2,900 kWh of electricity and 12,000 kWh of gas in a year, according to estimates from energy regulator Ofgem. This amounts to more than $3,600 in energy bills.

The numbers have been exacerbated by recent societal changes. According to a UK government report, domestic energy consumption in the country increased by 5.2 percent last year compared to 2021 due to increased remote working.

Add in the concerns over energy security which have arisen since the conflict in Ukraine, and it only strengthens the need for change, says Tadj Oreszczyn of University College London's Energy Institute.

"If we're going to try and make it more cost-effective to heat your house and run your house and tackle climate change and tackle energy security, which are three big issues, then what we need to do is we need to try and reduce energy demand and decarbonize our supply of energy," he says. 

While innovative building materials like hempcrete could boost energy efficiency, Oreszczyn believes we can all play our part with small behavioral changes in energy usage.

"Many people dry clothes on radiators," he says by way of example. "It's not a sensible thing to do and we probably shouldn't do it."

Still, the construction industry is responsible for 25 percent of the UK's total carbon emissions, with conventional concrete accounting for majority of this footprint. It's hoped that hempcrete and other bio-based construction materials could be an important building block towards net-zero construction.


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