When the heat kicks on in your home, you might encounter an offensive odor emanating from the floor vents. Because you can't block floor vents — you trap the hot air that way — you need another option for dealing with the smell. Rather than allowing this odor to infiltrate your home, combat it with an aromatic solution.
Tear fragrant dryer sheets into 1/2-inch strips. Affix the dryer sheets to the vent with double-sided tape. By tearing the sheets into 1/2-inch strips, you don't block the vent and restrict airflow. As the heat escapes through the floor vent, it carries the scent of the dryer sheets with it.
Attach a clip-on air freshener to the floor vent shutters or holes. An air freshener gives off a pleasant aroma that neutralizes the smell of the heat kicking on.
Apply dabs of fragrant essential oils to the floor vents. Put some of the essential oil on your finger and rub your finger against the vent to help it pick up the aroma.
Fill a sachet bag with dried lavender. Tie the bag and place it next to or on top of the floor vent. Natural dried lavender emits a fragrant smell that will be blown around the room when the heat kicks on.