Need a quick refresher on green building basics? This is our “Green Building 101” series that we’ll publish throughout the month. We’ll visit topics that form the foundation of our understanding of green building today.
What is energy efficiency?
Using less energy to accomplish the same amount of work. Getting the most work per unit of energy is often described as a measure of energy intensity. Common metrics for buildings and neighborhoods include energy use per square foot and use per capita.
Why is this important for buildings?
Energy has emerged as a critical economic issue and top priority for policymakers. Unsustainable energy supply and demand have serious implications for everything from household budgets to international relations. Buildings are on the front line of this issue because of their high consumption of energy. Studies have repeatedly shown that efficient buildings and appropriate land use offer opportunities to save money while reducing greenhouse gas emissions.
The current worldwide mix of energy resources is weighted heavily toward oil, coal, and natural gas.In addition to emitting greenhouse gases, these resources are nonrenewable: their quantities are limited or they cannot be replaced as fast as they are consumed.Though estimates regarding the remaining quantity of these resources vary, it is clear that the current reliance on nonrenewable energy sources is not sustainable and involves increasingly destructive extraction processes, uncertain supplies, escalating market prices, and national security vulnerability. Accounting for approximately 40% of the total energy used today, buildings are significant contributors to these problems.
What are strategies that increase energy efficiency?
- Address the envelope. Use the regionally appropriate amount of insulation in the walls and roof and install high-performance glazing to minimize unwanted heat gain or loss. Make sure that the building is properly weatherized.
- Install high-performance mechanical systems and appliances. Apply life cycle assessment to the trade-offs between capital and operating costs, and evaluate investments in energy efficiency technologies. Appliances that meet or exceed ENERGY STAR requirements will reduce plug load demands.
- Use high-efficiency infrastructure. Efficient street lighting and LED traffic signals will reduce energy demands from neighborhood infrastructure.
- Capture efficiencies of scale. Design district heating and cooling systems, in which multiple buildings are part of a single loop.
- Use energy simulation. Computer modeling can identify and prioritize energy efficiency opportunities.
- Monitor and verify performance. Ensure that the building systems are functioning as designed and support the owner’s project requirements through control systems, a building automation system, and commissioning and retrocommissioning.