A tractor heat houser channels heat from the engine into the operator area of the tractor. Tractor heat housers typically appear on vehicles that don't have enclosed cabs, such as lawn tractors. Depending on the model, heat housers are available with or without a windshield.
Heat housers can be full enclosures with zippered doors leading to the driver's area, or they can be just tall enough to contain the heat around the driver. The latter style often includes a canopy or collapsible roof to help contain the heat and protect the driver from the elements. Heat housers appear more often on larger lawn tractors used in the agricultural or landscaping fields.