Green design can help reduce energy costs in several ways. Buildings, transportation, and industry are the three largest contributors to carbon footprints. Some strategies to reduce costs include creating an energy audit and sustainability plan, improving lighting and HVAC systems, banning space heaters, installing water-efficient fixtures, using drought-tolerant landscaping, recycling, and encouraging tenants to conserve energy. Leading by example and involving tenants can help lower a building's carbon footprint and costs.