For most rooms including bedrooms, living rooms, downstairs hallways and even the loft space we recommend using optical smoke alarms. They are designed to quickly detect smoke from all sources and are particularly quick to detect smouldering fires, as well as being less prone to false alarms caused by steam and fumes created by everyday cooking and fireplaces under normal, safe circumstances.
Previously, ionisation smoke alarms were recommended for some rooms, but this older technology utilising radioactive material has been phased out of production globally in favour of optical detection.
For kitchens and garages, we recommend using heat alarms as they detect heat and not smoke, making them ideal for rooms where smoke fumes, vapours, dust, and damp are common.