The more lumens that are emitted, the brighter the lights will be, creating a more secure area. The amount of lumens required depends on the type of outdoor light used:
It is common for LED security lights to be installed at a minimum height of 8-12 feet and a maximum height of about 20 feet. This height range is typically great for keeping intruders away. The height is also perfect because it gives enough space for the motion sensors to work.
The height also leads to an optimal light beam spread which is the amount of coverage below the security light.