Why Do Firefighters Break Windows? In this video from a fire Engine 6 responded to, you’ll see Squad 3 being told to “start taking windows” after water was on the fire. This tactic is called horizontal ventilation—and it’s a critical part of fighting a house fire safely and effectively. Here’s what that means: 1. It helps get the heat and smoke out. Once water is hitting the fire, we clear windows to let the toxic smoke, gases, and heat escape. This cools the interior, clears the air, and gives