In a continuing effort to upgrade their facilities NASA has targeted some older buildings for upgrades to their HVAC systems. The “Reliability, Safety, and Energy Upgrades to Building Systems for Site Critical Building 4708” is one such project in which several building systems are being replaced with newer more energy efficient systems. During this project several areas of the building are receiving new air handling units, ductwork, boilers and pumps, new building automation controls, electrical and energy efficient lighting, and new acoustical ceilings. The existing plumbing fixtures are also being removed and replaced with low water consumption fixtures and automatic flush valves and faucets to minimize water consumption. All of these systems are being replaced area by area while the building is still occupied. Planning and coordination are key elements during a renovation of this magnitude to ensure the building user’s needs are met and undisturbed. In all a total of (15) new air handling units are being replaced, and this represents about 70% of the overall project with hopes of the remainder of the building released in the short term.