Smoke Alarms are a must

Smoke Alarms are a NZ Building code requirement for new homes and must be installed on the escape routes on all levels within the house, including in every sleeping space or within 3.0m of every sleeping space door. The smoke alarms must be able to be heard by sleeping occupants on the other side of closed doors. The two types of smoke alarms most commonly installed in homes are;

• Mains Powered Smoke Alarms connected to the home’s power supply. These alarms often have a battery back-up and can also be connected with each other so that when one operates, they all sound. This is considered by experts as the ideal system.
• Stand Alone Battery Operated Smoke Alarms with a 9V battery. Remember, these are not connected to each other. Batteries must be checked and replaced regularly to ensure ongoing reliability.

Be careful not to install Smoke Alarms in areas where they could create false alarms from things such as burning toast. Smoke alarms need to have a "hush" facility so the alarm can be turned off without removing batteries.