The present disclosure is directed to methods and systems for inspecting insulated equipment for any corrosion under insulation (CUI). The system includes a device comprising transmitter and receiver horn antennas, a vector network analyzer operatively connected to the antennas, and an infrared detector. In the method, a location for inspection of the equipment is identified. A metal jacket surrounding the location is removed without stripping the insulation. Microwaves are transmitted by the transmitted horn antenna at the location, and provide heating at the location. The microwaves are received by the receiver horn antenna after reflection off the equipment. The vector network analyzer analyzes the microwaves. The infrared detector detects infrared waves emitted from the location and develops an infrared image of the inner surface of the equipment. Based on the analysis of the microwaves and the developed image, a programmed processor determines whether CUI exists at the location.