DESIGN CONSIDERATIONS
SUSTAINABILITY AND ENERGY
- The building shell should be a major part of the sustainable strategy.
- At a minimum, the shell should:
- Contribute to minimizing energy usage.
- Incorporate environmentally sensitive materials.
- Ensure good indoor air quality and occupant comfort.
- Be durable.
- For high-performance building projects, the enclosure could help generate energy, return nutrients to the environment, and filter pollutants.
- One area of special concern for the building shell is durability, even though it currently is not included in LEED evaluations in the United States.
- The building superstructure and enclosure are frequently portions of the building that should last the longest and are the most difficult to repair or replace.
- Buildings that perform well for many years slow or reduce the consumption of resources and the wastestream.
- Failures of the enclosure can lead not only to water-damaged materials needing repair or replacement but also to unnecessary long-term energy consumption, toxic mold, and sick buildings.
- Buildings are major consumers of energy, so the enclosures should be part of a strategy to reduce energy consumption.
- In fact, creating a well-performing enclosure is considered to be the first step in reducing energy usage, ahead of other more sophisticated strategies, such as high-performance mechanical systems.
- A thorough understanding of the interior and exterior environments is paramount.
- For residential buildings in cold climates, heat loss through the enclosure may be the largest component of total energy consumption.
- For large commercial buildings in a moderate environment, daylighting schemes may save more energy, even as they may result in an enclosure with lower thermal resistance.
- Most jurisdictions require compliance with an energy conservation code.
- ASHRAE 90.1 and the International Energy Code (in various editions) are common model codes.
- These minimum standards should be exceeded by 20 to 50 percent, if possible.
