What Happened?
The Los Angeles City Council recently updated its Municipal Building Code requiring all new and refurbished homes to have a cool roof rather than roofing materials that absorb heat. The cool roof materials naturally reflect sunlight, allowing homes to be cooler which lowers energy used for air conditioning and reduces injuries from overheating.
The Goal
The Los Angeles City Council’s decision came after Climate Resolve held a conference on cool roofs this year discussing the eco-friendly benefits of replacing hot roofs with more efficient materials. Lower energy costs and greenhouse gas emissions are a top priority, particularly when temperatures in Los Angeles are projected to increase between 3.7 and 5.4 degrees Fahrenheit in the near future, which may triple or quadruple the number of extreme heat days throughout the area.
The Los Angeles Department of Water and Power added new cool roof incentives to support the initiative, enabling the city to fund the addition of cool roof materials to new and existing homes throughout the city. The ordinance aims to:
- Keep residents and infrastructure safer on extreme hot days
- Reduce the number of hospitalizations and deaths from overheating
- Improve air quality with lower ozone formation
- Protect against power outages
- Lower electricity bills and greenhouse gas emissions
- Boost the quality of life for residents
Los Angeles is the first major city in the country taking legislative steps to mandate green building codes to protect against high energy consumption and the urban heat island effect. In direct response to climate change and demand for more efficient amenities, white or cool roofs are growing in popularity.
New Roofs
According to the U.S. Environmental Protection Agency, the urban heat island effect occurs when certain regions are significantly hotter than nearby communities. Cities with more than 1 million residents typically experience mean air temperatures of 1.8 to 5.4 degrees Fahrenheit higher than surrounding cities. The result is higher energy usage, air conditioning costs, air pollution, greenhouse gas emissions and heat-related injuries or deaths.
The EPA has several recommendations for ways to mitigate heat island effect such as planting more vegetation, implementing cool roofs and pavements, and launching green roofs. Cool roofs and pavements offer many benefits including:
- Reduced energy consumption, air pollution and greenhouse gas emissions
- Less solid waste generation with lowered demand for re-roofing
- Improved stormwater management and water quality
- Increased surface durability with enhanced nighttime illumination
Green roofs, on the other hand, involve residents planting vegetative layers on a rooftop that removes heat from the air through evapotranspiration. The temperature on the roof surface is also lowered, allowing the building to consume less energy for cooling while also providing insulation to reduce heating bills as well.
The EPA estimates a green roof installation will cost $10 per square foot or up to $25 per square foot for intensive roofs. Maintenance costs for the roofs can vary from $0.75 to $1.50 per square foot annually. The materials needed to implement a green roof are more expensive than standard roofs, however the savings from energy efficiency greatly outweighs those initial expenses.
Green Buildings
Gov1 has followed the growing popularity of green and cool roofs as well as financial incentives used to encourage eco-friendly building.