The design and construction of buildings in hot-humid climates requires high energy consumption typically for air conditioning due to higher thermal loads. Regionally, there is a rising concern on the current rate of energy consumption due to air conditioning. Considering the wider impacts of carbon emissions on our climate, and the need to reduce these emissions, effective energy efficiency solutions are necessary in order to achieve the overall goal of reducing carbon emissions. This paper presents the simulated and measured efficiencies of the “All in One” 15 TR (52 kW) fully integrated HVAC systems driven by-product of rejected brine, waste heat and renewables. The tested system is locally manufactured and installed in a testing facility at Qatar Science and Technology Park (QSTP). The system has shown more than 60% reduction in energy consumption compared to conventional systems. © Indoor Environment for Hot Climates – ASHRAE, HotClimates 2017.All Rights Reserved.