Metal Halide lamps are an extremely efficient form of lighting, which is why they are found to be lighting all sorts of buildings, usually as security lights. The light output is around 10 times that of the equivalent wattage Halogen light. For example a 35 watt metal halide will be equivalent to around a 300 watt Halogen. Output differs according to the make and colour temperature. Generally cool whites have a brighter output than warm white but are not always the best colour for every application
Metal halide lamp technology is super bright and very energy efficient. Unlike standard lamps metal halide lamps do not like to be switched on and off quickly as they need time to both warm up and cool down.