Lots of good points here. (Especially about frozen pipes where I live 🙂 Whether or not you have a sprinkler system must depend on your individual circumstances, but having enough smoke alarms is a must – and also have a plan for making sure the batteries are working. Maybe include a regular test just before Shabbos (when a lot of fires occur in our community) or at least Rosh Chodesh.
And definitely have hand fire extinguishers where you can get them easily, and keep them charged. Fires move fast. I recently had a fire and discovered that my fire extinguisher had expired. BH I was able to put it out, but it was close. The house would have been gone before the fire department could get there. Fire blankets are also a good purchase. Likewise Health’s idea of a ladder for the second floor. And have fire drills, so your kids know exactly how to get out.
Important to make sure all your electrical appliances are safe, too. There was a fire in Brooklyn a few years ago where seven children (I think that was the number) were killed, and it was started by a Shabbos electric plate. (They also had no smoke alarms.)
Best of all – contact your local fire department and they will give you all the info you need. Stay safe!