Laboratory facilities are energy intense building types due to the vast amounts of 100% outside air required. With today's concerns over high energy expenses, reducing carbon footprints, plus efforts to make facilities' green and provide a better indoor environment, reducing both new and existing lab facility energy expenses has become a critical challenge particularly in hot and humid climates where the cost of conditioning this vast amount of outside air can be prohibitive. The primary reason behind many labs' high energy expenses is the minimum ventilation or air change requirements that often dominate the amount of outside air required by these facilities. This paper will present a proven Demand Based Control solution to this problem. In this approach that is referred to in the ASHRAE handbook, rather than use a fixed air change rate of 6 to 12 ACH (Air Changes Per Hour), real time measurements of the actual lab indoor environmental quality are used to vary the air change rates from as low as 2 to 4 ACH to upwards of 8 to 16 ACH based on the cleanliness of the lab room air. By safely cutting the lab air change rates often times by as much as 50% or more for about 98% of the time, this approach is often cited as the single largest energy conservation approach for many lab facility designs. Furthermore in new designs significant net reductions in first cost may also be achieved through reductions in the sizing of the HVAC systems. Finally by significantly increasing air change rates when contaminants are sensed, improved Indoor Environmental Quality (IEQ) can be achieved. This paper will describe this successful approach for labs and vivariums plus discuss the technology used to implement it cost effectively. Additionally, the results will be shown for the largest study ever done of lab IEQ conditions covering over 1.5 million hours of lab operation. Furthermore a variation of this concept is often applied to other types of facilities such as office buildings, educational facilities, public assembly buildings such libraries and student centers, as well as healthcare facilities. This approach has been used in over 400 buildings including well over 200 lab facilities and two case studies will be highlighted such as a full lab building retrofit of the 2006 R&D Lab of the year at Arizona State University which is saving over $1 million a year in annual energy costs from this concept. Finally, a highly sustainable, "near zero carbon" lab project in the often hot and humid climate of Abu Dhabi, UAE will also be discussed.