I Just Learned Why You Should Sleep With Your Bedroom Door Closed — And It Could Make a Life-Saving Difference

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Now imagine the same situation with the bedroom door completely closed.

That barrier can restrict the flow of smoke and heat into the room.

Research summarized by the NFPA Fire Protection Research Foundation notes that compartmentation, including room doors, can slow the spread of fire and smoke and increase available safe escape time.

That’s the science behind the memorable phrase:

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“Close Before You Doze.”

The Temperature Difference Can Be Dramatic

This is the part that makes people pay attention.

Fire Safety Research Institute educational materials show that conditions behind a closed door can be dramatically different from those in areas directly exposed to a fire.

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FSRI’s campaign describes experimental scenarios in which a closed room remained around 100°F while exposed areas could reach roughly 1,000°F. The organization also reports major differences in carbon monoxide concentrations between open- and closed-door conditions in its demonstrations.

Those numbers aren’t a promise that every house fire will produce exactly those temperatures or concentrations.

Every fire is different.

The structure, fuel, ventilation, fire location, door construction and many other variables affect what happens.

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The broader lesson is what matters:

A closed door can substantially change the environment on the other side.

Your Bedroom Door Is Essentially Creating a Compartment

Firefighters think a lot about controlling airflow.

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Fire needs oxygen, and opening doors and windows can change how air moves through a burning structure.

Closing a bedroom door creates separation.

That can help restrict the movement of heat and combustion products between spaces.

FSRI says closing doors can help isolate fire flow, reduce room temperatures and keep carbon monoxide levels lower.

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That cheap hollow-looking door suddenly doesn’t seem quite so useless.

But There’s an Important Detail Viral Posts Often Leave Out

This is critical.

Closing your bedroom door is not a substitute for working smoke alarms.