Researchers at Rensselaer Polytechnic Institute (RPI) in New York are to develop a commercially viable insulated siding product made with hemp “wool”.
The Hemp Retrofit Structural Insulated Panel (HeRS) project is being supported by a $1.5 million grant from the United States Department of Energy’s (DOE’s) Buildings Energy Efficiency Frontiers and Innovation Technologies (BENEFIT) initiative.
HeRS will consist of a mat of hemp wool fibers bonded with a recycled binder and a thin composite casing with a form factor and attachment method similar to existing siding materials. According to RPI, it will have a minimum R-5 thermal performance that will reduce heating, ventilation, and air conditioning (HVAC) energy use by a very significant 15%-25%.
Alexandros Tsamis, an architect and associate director of the Center for Architecture, Science and Ecology (CASE) at RPI and lead primary investigator on the HeRS project believes industrial hemp can revolutionise manufacturing in the USA
“By utilizing this versatile and renewable crop in building materials, we can create a building retrofit product that will not only be beneficial for homeowners and the environment but also has the potential to jumpstart regional circular economies throughout the United States based on renewable materials,” Mr. Tsamis said.
As well as creating design and manufacturing plans for HeRS, the embodied carbon footprint of hemp siding will be analysed and an availability study for supply chains will be conducted to demonstrate how US-produced hemp fiber can be effectively integrated into the production line of HeRS.
The 2024 BENEFIT funding opportunity announcement (FOA) supports the USA’s Affordable Home Energy Shot program, which calls for innovations in building upgrades, efficient electrification, and smart controls reducing the cost of decarbonizing affordable housing by at least 50%, while lowering residents’ energy bill by at least 20% within a decade.
Industrial hemp has been used in building applications for millennia, and it has enjoyed a resurgence in interest in recent years for modern building applications; thanks to changes in laws that previously banned growing of the crop in some countries. In addition to siding, hemp can used to create particle/chipboard, plaster/render, other forms of insulation and hempcrete; which is a mixture of industrial hemp hurd (the woody core of the hemp plant), a lime-based binder and water.
