Spring has sprung in Windsor. That means greener grass - and greener roofs and walls, too.

According to the Green Roofs for Healthy Cities Association, there has been a 24-per-cent growth rate among industries installing green roofs.

Joe Passa is a Windsor architect who has designed green roofs. He said they have their advantages.

"One is that [you're] recreating the ground you're building on, the same nature that was there before," he said. "Secondly, it provides oxygen back to the environment. and doesn't radiate heat on the roof."

According to the Green Roofs for Health Cities Association, the light absorbed by rooftop vegetation would otherwise be converted into heat energy.

The association also claims that plants are able to cool cities during hot summer months and reduce the Urban Heat Island (UHI) effect through the daily dew and evaporation cycle.

Green roofs also retain 70-90 per cent of the precipitation that falls on them, the association claims.

Passa said people think green roofs cost "so much more money." But he claims that's not true.

"It does not take extra money to do something as efficient as we have been doing," he said.

According to the Environmental Protection Agency in the U.S., the estimated costs of installing a green roof start at $10 US per square foot for simpler extensive roofing, and $25 US per square foot for intensive roofs.

The EPA also says annual maintenance costs for either type of roof may range from $0.75-$1.50 US per square foot.

Passa said the long-term gains offset the initial cost of building sustainable structures.

The EPA says something similar.

"While the initial costs of green roofs are higher than those of conventional materials, building owners can help offset the difference through reduced energy and storm water management costs, and potentially by the longer lifespan of green roofs compared with conventional roofing materials," the agency says on its website.

St. Christopher Catholic School in Windsor has a green roof that's visible from some parts of the school's second floor.

Teacher Mike Kosty said it improves the quality of life in the classroom.

"This is a wonderful sight," he said. "Here we are and we feel like we're outside just by looking out the window."

Green isn't just for rooftops.

Kevin Stelzer is the architect who designed the living wall in the engineering building at the University of Windsor.

"Sustainable buildings are better for humans," he said. "What do humans need? Great indoor air quality, sunlight, moisture. If a plant can thrive, it means there's good live, moisture, good sunlight."

Faculty members who teach in the engineering building say the indoor living wall adds to the atmosphere and makes the building healthier.

"The clean air, the breathability, it made a lot of difference. It was almost instantaneous," engineering professor Andy Jenner claimed.