Various disclosed embodiments include illustrative heating, ventilation, and air conditioning (HVAC) devices, HVAC systems, vehicles, and methods. An illustrative HVAC system includes a case configured to at least partially recirculate air within the case, a blower disposed in the case and configured to cause air to flow, a first heat exchanger disposed in the case and configured to heat the air, and a second heat exchanger disposed in the case and configured to exchange heat with the air.