How long do I need to let the fireplace fire die down before closing it up for the night or leaving home?

It’s important not to close a hot chimney flue too quickly since there could still be combustibles in the flu. Letting it cool completely (at least one hour) will prevent creosote buildup which may result in a dangerous chimney fire. Also, make sure that children and pets aren’t in the house when shutting down for the night.