Retrofitting an existing masonry cavity walled building with a green or living wall can reduce the heat lost through its structure by more than 30%. Researchers retrofitted an exterior wall with a flexible felt fabric sheet system with pockets allowing for soil and planting. Daytime temperatures within that newly-covered section remained more stable than the area with exposed masonry, meaning less energy was required to heat it. Since space heating can account for over 60% of all energy used in buildings, this could be helpful. If you add a grow light you could even produce some of your own food.
www.sciencedaily.com/releases/2021/11/211124154121.htm