The cheapest and most common type. Very sensitive to small particles of smoke from "flaming" fires like chip pans. Will detect this type of fire before the smoke gets too thick.
More expensive type but more effective at detecting larger particles from "slow burning" fires such as smouldering foam or P.V.C. wiring.
For maximum protection one smoke alarm per room except the bathroom, kitchen and garage. Heat alarms may be considered where fumes from cooking or smoke from cigarettes or open fires could lead to unwanted alarm activations.
For minimum protection one smoke alarm for each level/floor of your home.
On the ceiling as close to the centre of the room as possible.
Keep in mind your ability to hear the smoke alarm at night with the door closed.
The purpose of a Smoke Alarm is to give an early warning of an outbreak of fire! It is vital that you and your family know exactly what to do when the Smoke Alarm activates.