Along with benefits such as air purification and noise reduction, “living walls” are also claimed to help regulate the temperature within new buildings which they’re built into. A recent study now indicates that they have the same effect when added to much older, existing structures.

Led by Dr. Matthew Fox, a team at Britain’s University of Plymouth started by installing a plant-filled living wall facade on one section of the west-facing exterior wall of a pre-1970s building on the campus.

That structure already featured masonry cavity walls, which incorporate two parallel sub-walls separated by an air space. In this case, the inner wall was made of concrete, and the outer wall was brick. The added living wall was made up of a series of linked felt pouches, each one of which contained soil and winter-hardy plants.

After measuring the room temperature (and thermal conductivity of the walls) within the west-facing side of the building over a five-week November/December period, it was found that the section with the living wall lost 31.4 percent less heat than an adjacent control section. Additionally, daytime temperatures within the living-wall-covered section were more stable, meaning that they swung up and down less in response to factors such as sun exposure and outdoor ambient temperatures.

As a result, less energy was required to heat that part of the building.

Keep reading on New Atlas