This paper summarizes investigation into the strategies, methods, and best practices for achieving low HVAC load on two existing vehicles programs. Decreasing the load required from the HVAC system will help improve the fuel economy of the truck resulting in a cost savings to the customer.A thermal analysis was performed on two truck cabin interiors to calculate the amount of energy necessary to maintain a desirable internal cabin air temperature while under certain environmental conditions. In order to quantify how much cost is associated with running the HVAC system with its current design, the thermal analysis was coupled with a computational fluid dynamics simulation to understand the complicated flow patterns inside the cab while the HVAC system is operational. The load on the HVAC system was calculated for each scenario using the thermal model and the results were compared to the benchmark. These results were then used to help quantify the most cost effective solutions to improve the performance of the HVAC system and hence reduce the energy consumed to maintain cab comfort.