Delmar Online Training Simulation: HVAC, is a 3-D, immersive simulation that offers a rich learning experience that mimics field performance. It challenges learners to master diagnostic and troubleshooting skills across five pieces of HVAC equipment found in industry- Gas Furnace, Oil Furnace, Boiler, Small Commercial Air Conditioner and Central Air Conditioners. Soft skills are also included within the Simulation. To create successful learning outcomes, the Delmar Online Training Simulation: HVAC offers more than one hundred scenarios which allow students to troubleshoot and build diagnostic and critical thinking skills. Two modes within the Simulation promote incremental learning: Training Mode has fixed scenarios to aid in initial familiarization with the equipment, the problem needing attention and the capabilities of the Simulation; Challenge Mode is randomized with 3 levels: Beginner, Intermediate, and Advanced. Both modes require learners to diagnose a fault or faults and perform the repair successfully while materials and labor costs are tracked. Online access is for two years upon activation. The instructional design allows for full open engagement, so students do not have artificial guard-rails leading them to a conclusion. Combining sound instructional design with top-quality computer immersive technology, learners develop critical thinking skills and apply them to real-world customer service calls in a simulated, 3-D, life-like setting. This performance simulation complements live training practice by re-enforcing good habits, and even presenting scenarios that are impractical (dangerous, expensive, etc) to create in labs or in a residence.