Green Roofs
Inefficient roofs account for about 20-30% of heating and cooling stretches the homeowner’s energy budget. Green roofs can help reduce this by absorbing heat and providing insulation. Green roofs cost roughly $10 to $30 per square foot of roof.
Type of Green Roofs
Extensive Green Roofs
Extensive green roofs are self-sustaining. Although extensive green roofs are not as good as intensive green roofs at absorbing heat, it is the more cost-effective option. This is the better option for homeowners
Intensive Green Roofs
Intensive green roofs are more expensive and require more maintenance, but they absorb much more heat, while also providing a space for people to explore. This is the better option for commercial buildings.
Benefits
Improves energy performance to amplify insulation
Green roofs can improve energy performance more than typical roofs by evapotranspiration. When there is daylight, the green vegetation on roofs reflects the heat from the sun. As the temperature from sunlight reflects, and the moisture in the vegetation transpires up the vegetation and evaporates. As the moisture in the vegetation decreases, green roofs reduce the temperatures inside the house controlling the humidity inside a house.
Save money
Many people pay too much for air conditioning. High-voltage air conditioning units may work extra hard from wasting energy and electricity to cool the house. Most cooling systems can be costly because of how coolants like Freon are in short supply but have high demand. Rather than refilling Freon into A/C, which only lasts for 2-5 years, green roofs can last from 30 to 50 years, making them a more sustainable option for providing HVAC heating and cooling systems to heat your home.
Mitigate urban heat island effect
In environments with limited vegetation, cities typically experience warmer temperatures than rural areas.Vegetation from green roofs provides shade for the roof surfaces, reducing the temperature of the roof surface by 30-40 degrees Fahrenheit and ambient temperatures by 5 degrees Fahrenheit. By doing so, green roofs can reduce the excessive building energy use, thus saving $0.23 per square foot of roof and giving a stronger quality of life towards other individuals.
Enhances stormwater management
Green roofs act as a sponge. The vegetation can retain the stormwater when it rains, and releases it through evaporation when the sun is out. This helps filter polluted runoff from the rainfall, thus improving the water quality In addition, rainwater can be harvested in the green roofs to supply household demand, and saving the water bill on your home.
Tax Rebate
Provides homeowners a 30% tax rebate for qualified green roofs (US Clean Energy Stimulus and Investment Assurance Act of 2009 (S.320)) which applies to new and retrofit projects that require at least 50% of roof to be covered with green roof
In the city of Seattle, building a green roof saves money off of annual drainage bill if the homeowner’s property has a functioning stormwater system