Getting Started > Energy Codes 101

What are energy codes?

Energy codes are a subset of a broader collection of written legal requirements known as building codes, which govern the design and construction of residential and commercial structures. Building codes protect individuals from substandard living and working conditions by setting minimum standards for acceptable practice. Energy codes address increasing the energy efficiency of building systems.

How do they work?

Energy codes reference areas of construction such as wall and ceiling insulation, window and door specifications, HVAC equipment efficiency, and lighting fixtures. Specific code provisions depend on an individual county’s climate zone. Usually, there are two methods for compliance. The most common method is the prescriptive approach, in which the code stipulates the stringency of the materials and equipment the builder must use. For the performance approach, the code allocates a total allowable energy use for proposed building, and the design team can choose the materials and equipment that will meet this target. For commercial buildings, compliance with the performance path can be shown through energy modeling software. The performance path allows for greater flexibility and creativity. In recent years, there has also been an increase in support for outcome-based codes, where the actual building energy usage intensity (EUI) is used to verify whether the project is code compliant.

Where did they come from?

In the United States, national model energy codes were created in response to the energy and economic crises of the 1970s. In 1978, Congress passed legislation requiring states to initiate energy efficiency standards for new buildings. Since then, energy codes have undergone significant improvements. The Energy Policy Act of 1992 (EPAct) mandated that all states must review and consider adopting the national model energy standard. The Energy Policy Act of 2005 specified the most current model energy codes at the time of its passage (2004 IECC supplement, ASHRAE 90.1-2004). In 2009, when states accepted State Energy Program funding as a part of the American Recovery and Reinvestment Act (ARRA), they also agreed to adopt a building energy code for residential construction that was equivalent to the 2009 IECC and one for commercial buildings that was equivalent to ASHRAE 90.1 2007.

Today, ASHRAE Standard 90.1-2013 and the 2015 International Energy Conservation Code (IECC) are the national model energy codes, and each is updated on a three-year cycle.

Why adopt energy codes?

Energy efficiency is often acknowledged as the quickest, cheapest and cleanest way to reduce energy use and lower greenhouse gas emissions, and nowhere is this more apparent than with the building sector. In 2014, EIA found that 41% of total U.S. energy consumption could be attributed to residential and commercial buildings. Moreover, the average lifespan of a building is roughly 50 years, meaning that building energy policies today will affect building energy usage until 2065 and beyond. It is imperative, therefore, that we take advantage of this largely untapped source for energy savings.

Read more about energy codes and climate change here.

The benefits of adopting and implementing building energy codes affect our world on the individual, societal and global levels, and their long-term policy implications – on issues ranging from sustainable growth and climate protection to global health and energy security – are significant and widespread. The primary function of energy codes is to reduce building energy consumption, which reduces greenhouse gas (GHG) emissions and pollution from the combustion of fossil fuels. However, it also lessens national peak energy demand and dependency on imported energy sources, which increases utility system reliability and national energy security, respectively. Moreover, energy codes create a more comfortable living and working environment through improved indoor air quality, and they help occupants save money by reducing energy bills, which stimulates the economy.

What are mandatory codes?

Mandatory codes are building energy codes adopted by the state for all buildings. While code enforcement is usually carried out at the county or city levels, local jurisdictions are nonetheless required to assure code compliance. The state code sets the minimum level of energy efficiency for residential and commercial new construction statewide.

Read DOE’s “Building Energy Codes 101: An Introduction”.

Codes in Home Rule states, or in states with recommended standards, are adopted and implemented at the discretion of local jurisdictions. This approach results in a state landscape with different requirements city to city, or county to county. Often there are locations with no energy requirements at all. The lack of a consistent minimum standard requires builders and engineers to put additional work into tracking requirements for each location and factoring that into their designs. It also means that homebuyers and building owners are not purchasing the same quality of buildings around the state, nor saving the same amounts on their energy bills. If there are no energy codes, good builders and engineers who build to a cost-effective off-the-shelf level of efficiency are competing for buyers with those buildings where corners have been cut on energy to reduce cost – all in an environment where these costs are hidden from the buyer. A mandatory baseline ensures an even playing field for builders and engineers.

National model energy codes are developed every three years to provide support to the states; most states adopt these codes as is or with minor amendments. In states without mandatory codes, we recommend leveraging local up-to-date code adoption or state requirements for state-owned or funded buildings to support the argument for state-level policy.

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This page was last modified on: February 13, 2017