Microwaves do not need to be vented outside of your home, and they are designed to operate as a self-contained appliance. Unlike conventional ovens or stovetops, microwaves do not produce combustion byproducts, so they do not require an external venting system like a range hood.
When you use a microwave, it generates electromagnetic waves that heat the food directly inside the cooking chamber. The microwaves are contained within the oven, and the energy is absorbed by the food, causing it to heat up. Any steam or vapors produced during the cooking process will remain inside the microwave, and the oven is equipped to handle this safely.
As a result, you do not need to vent the microwave through an open window or any other external ventilation system. However, it's essential to ensure that the microwave's vent and exhaust system (if your model has one) are kept clean and free from obstruction to maintain optimal performance and prevent any potential issues with excess moisture or odors within the microwave.