Cooling energy reduction of up to 25% or more has been attributed to cool metal roofing materials. Municipalities are embracing them to mitigate the urban heat island effect that can make daytime temperatures within the city higher than normal and prevents heat dissipation at night. Cool metal roofs can decrease the demand on the energy grid during the summer by lowering peak demand.
A cool metal roof is a crucial part of an energy efficient structure, one that receives the majority of the sun’s rays and has the maximum impact on solar heating. Since energy-efficient construction is now in the mainstream, codes and standards are being developed to ensure quality and to encourage further adoption.
Who is developing the codes and standards?
EPA: Energy Star
The Environmental Protection Agency (EPA) released the voluntary Energy Star program in 1992 and it continues today, providing information on saving energy and conferring Energy Star certification and recognition to home and building construction. If the Energy Star provisions for HVAC, water efficiency, and other items are met, a builder can provide Energy Star documentation to go with the structure.
U.S. Green Building Council: LEED
Perhaps the most well-known right now is the Leadership in Energy and Environmental Design (LEED) program from the U.S. Green Building Council. Also a voluntary program, USGBC has put together a point system where a structure can earn a particular LEED level:
Builders can also earn a LEED certification showing they have the skills to build a green home or building to USGBC standard.
International code: IECC and IGCC
The International Energy Conservation Code was developed in 2000 as a model for states and municipalities to use in local and state building codes. The code sets minimum energy performance levels for each component of a building and residence. The code does not permit trade-offs in order to come into compliance; each code must be met or exceeded before the IECC announces it compliant.
The International Green Construction Code is the first to include sustainability measures for the construction project and jobsite. It establishes baseline green requirements to be used in conjunction with existing International Codes including the National Green Building Standard.
Since these become part of the state and regional building code, they are mandatory when used.
State and local requirements
Beyond national and international efforts to mandate energy efficient building materials, state and local regulatory bodies have initiatives to add cool roofs to the local building code.
- National Association of State Energy Officials
- California Title 24 Building Code
- Chicago Urban Heat Island
- American Society of Heating, Refrigerating, and Air-Conditioning Engineers ASHRAE
- New York Tax Incentive
- Florida White Roof Credit
- Georgia Energy Code
Communities are beginning to understand the savings that can be created with cool metal roof technology. With construction costs on the increase, they are continually seeking ways to keep utility, repair, and maintenance costs at a minimum to stave off local property tax increases.
Insurers also provide incentives in the form of lower premiums for buildings with metal roofs and frames.
The market for metal roofs continues to grow. Drucker Research found in a 2008 study that 14% of the total commercial market and 10% of residential were made up of metal roofs. That percentage has grown since then and is expected to continue to increase.
However, the amount of energy the U.S. is expected to require is also expected to grow, potentially by up to 45% or more by 2030, according to the Nuclear Energy Institute. The only way to meet that demand will be to increase energy efficient structures and tools.
Designing your building with a cool roof is the best way to meet green standards. A cool roof has:
- Increased solar reflectance, the percentage of all solar radiation reflected from its surface. The less solar radiation that is penetrating the roof, the less the internal temperatures will rise. The result is lower energy use for cooling.
- Increased emissivity, the amount of absorbed heat that is released into the atmosphere during night time cooling. When a roof cools faster it contributes less to the urban heat island effect and decreases the need for additional internal cooling at night.
- Balanced energy use from the increase in reflectance and emittance. The combination translates into lower amounts of smog. It also reduces temperature variations that can cause damage through movement.
Economically, the benefits continue. Energy savings and utility cost effectiveness lead the list but metal roofs provide a great deal more return on investment beyond those measures.
A metal roof is lightweight yet highly durable, capable of lasting for 50 years or more. With a high strength to weight ratio, a builder realizes savings on transport costs while the owner has a roof tough enough to withstand fire, high winds, hail, and seismic events.
A metal roof is also sustainable because the metal is typically derived from recycled materials. In addition, at the end of its life cycle, a metal roof is itself, recycled into new material. Metal roofing can be created with any color, texture, or appearance and creates a perfect platform for rooftop renewable energy systems.
Utilities and energy companies often provide cash incentives for using metal roofing materials because it decreases the local energy load overall. Tax incentives are also available for both builders and owners. DSIRE, or the database of state incentives for renewables and efficiency, contains a list of incentives available across the U.S. The American Recovery and Reinvestment Act of 2009 contains incentives for green building, some of which have been extended through 2016.
Cool metal roofing is moving from “nice to have” to “required.” Local, state, federal, and international building codes are following suit. As you have read, there are many voluntary codes and standards already in existence, which will continue to be updated. Some standards are already mandatory with other codes soon to follow.
The metal roofing industry should be ready to follow by upgrading skill sets, finding manufacturers, and building partnerships with other construction professionals in order to remain relevant and viable in the future.