What safety measures should be taken when installing a furnace in a closet with a door?

When installing a furnace in a closet with a door, it is important to ensure proper ventilation to prevent carbon monoxide buildup. The closet should have adequate space around the furnace for airflow and the door should have vents or louvers for air circulation. Additionally, the closet should be fire-rated and have a smoke detector installed for safety. Regular maintenance and inspections of the furnace are also crucial to ensure safe operation.