Fire rated downlights prevent both heat and flames from transmitting through the ceiling. Typically, these lighting fixtures have a 30 to 60 minute rating, but the best and most expensive ones can last up to 2 hours.
Building Regulations state that all commercial and residential buildings should be air tight. If you have more than one downlight that is not fire rated, air may escape through the holes. In loft areas and other cold spaces, these downlights work by drawing out the warm air in order to prevent fire.
Even if you do not think that fire rated downlights are that important for preventing the spread of a fire, it is still required by Building Regulations that you have them installed in your rooms. Some people are put off by the price of these downlights as they are a bit more expensive and instead, they opt for cheaper ones. Other types of downlights do not offer adequate moisture protection and fire resistance so for your own safety and peace of mind, you are recommended to have them installed in your home.