Reducing light pollution
When lighting the outside of a property you can use low wattage LED fittings which don't need the same levels of illumination as those used to illuminate inside a property, as you are not competing with other light sources, for example if you were in a field in the country with no other surrounding light you could easily see a light up to 5 miles away from a house.
Keep the lights local to the area you are trying to illuminate like an adjustable light over a BBQ area rather than one big flood light on the back of the house that lights the whole area. Again lighting a driveway entrance looks better using low level individual bollards rather than one big security light.
Be sympathetic to the environment and your neighbours in your design. Low energy LED lamps are now very popular and have a lower carbon rating than the older incandescent lamps we've been using for years and LED lamps help to reduce energy costs and your carbon footprint. Below we describe Lux levels.
Light levels ( LUX )
Light levels are measured in something called Lux. Put simply Lux is a measurement of light falling on a given surface area. For example an average Lux of 200 would be needed for an outdoor tennis court for recreational purposes, a side street pavement would have an average of just 5 Lux and a typical office environment would require 500 Lux on the desk.
To calculate lux levels you need a very good calculator or computer as there is a number of factors that need to be taken into account. Beam angles of a light would also have a bearing on the light levels, the tighter the beam angle the more concentrated the light will be and therefore the Lux level would be higher.