A residential fire has left five Londoners without a home after flames tore through their dwelling, causing an estimated $200,000 in damage according to the London Fire Department.

Fire investigators are currently on scene working to determine the origin, cause, and circumstances surrounding the blaze. The investigation is ongoing as officials piece together exactly what sparked the destructive fire.

Here’s where this story gets genuinely heartwarming though—the sole occupant who was inside when the fire started made it out completely unharmed. And they have their smoke alarm to thank for that lucky escape.

When firefighters arrived at the scene, they found all smoke alarms in the dwelling were actively sounding, having done exactly what they’re designed to do: alert residents to danger and give them precious time to get out safely.

The London Fire Department is using this incident as a real-world reminder that smoke alarms aren’t just helpful—they’re literally life-savers. According to fire officials, having working smoke alarms in your home isn’t optional; it’s actually required by law.

The specific requirements are pretty straightforward: every home needs a working smoke alarm on each storey and outside all sleeping areas. It’s one of those things that seems basic until you actually need it, and then you’re incredibly grateful it’s there.

While the property damage is substantial at over $200,000, the fact that everyone got out alive makes this a story with the best possible outcome given the circumstances. The Red Cross has stepped in to provide assistance to the five individuals who have been displaced by the fire.

This incident joins countless others where properly functioning smoke alarms have made the difference between a close call and a tragedy. The London Fire Department continues to emphasize through their ongoing safety campaigns that when it comes to smoke alarms, there really are no ifs, ands, or buts—they save lives.

Fire investigators will continue their work to determine what caused the blaze, working alongside the London Police Service as part of the standard investigation process for incidents of this magnitude.