Smoke detectors have been manadatory in NSW for some time now and it is easy to understand why. They do save lives. Hard wired smoke detectors are the best choice but in terrace houses similar to what you find in areas such as Paddington you may need to use battery operated smoke alarms. These are a great alternative when there is no option of hard wiring them. There are 2 main types of smoke detectors, ionisation and photoelectric. Ionisation is your standard smoke detector. Photoelectric smoke detectors are used when they are positioned close to kitchens. Photoelectric detectors are less prone to false alarms such as whn you are cooking food. The brands that I use are Clipsal, HPM AND PDL smoke detectors.