When using aluminum coils indoors, it's crucial to ensure proper ventilation to prevent the buildup of gases that can be harmful if inhaled in large quantities. Always follow the manufacturer's guidelines for installation and operation. Keep the coils away from flammable materials and ensure they are securely fastened to prevent tipping or falling. Regularly inspect the coils for any signs of damage or wear, and replace them if necessary. Never use aluminum coils in enclosed spaces without proper exhaust systems, and always have a fire extinguisher nearby in case of emergencies.