Burglary
Home Security Lighting
The form of lighting currently found many domestic locations is a 250 or 500 watt tungsten halogen floodlight controlled by a movement sensor (passive infra-red, PIR). This is unfortunate, as in many locations it is inappropriately installed and other forms of lighting could make for a better choice.
PIR-controlled floodlights
Illuminate only when the criminal has picked a house and crossed its boundaries. This is too late and does not deter criminals when it matters most, namely when they are selecting a house.
Emit a harsh, intrusive and environmentally unfriendly light that is often a serious nuisance to neighbours (The Chartered Institute of Environmental Health reports increasing complaints of nuisance from this type of lighting). Lights where the PIR can be overridden to be switched on permanently can also cause nuisance.
Instantly switch on a powerful white light, resulting in a ‘flash factor’ that disturbs rather than aids human vision. When located near roads, this can be positively dangerous. Equally, badly adjusted and aimed lights can cause dark shadows due to their high intensity light.
Are extremely energy inefficient
Require regular bulb replacements
Are easily interfered with unless installed at the recommended height of more than 10'
Can be so unreliable that they are quickly discredited by householders and neighbours - common sense suggests that few people will check why a light has activated, assuming they have seen it activate
Can increase the fear of crime amongst the most vulnerable by regularly activating for no apparent reason.
The alternative is to use high efficiency low energy lighting controlled by a photo-electric cell (dusk to dawn switch). Such low wattage lighting, on permanently during the hours of darkness, provides a more than adequate level of illumination, is not as harsh and is more environmentally friendly than tungsten halogen floodlights. A low wattage unit placed out of easy reach at a height of eight to ten feet could illuminate an average rear garden, helping to create a reassuring environment and hopefully playing its part in deterring the burglar from selecting that house in the first place. In cost terms, the low wattage ensures that even though the light is on all night, the cost to run is minimal - no more than a few pound a year.
PIR switched tungsten halogen floodlights can cause problems, and due to some of the issues highlighted above, may provide little in the way of extra security for a domestic dwelling. They appear to be popular because many people think that PIR is the “right thing” in security terms. However, low wattage lighting provides a more constant level of illumination with fewer shadows. All of this assumes that the area being lit can be overlooked as there would be little point in lighting an area which cannot be seen, except in practical terms for the householder.
In conclusion, for security purposes, and from the Secured by Design perspective, the first choice in security lighting is the low energy photo-electric cell controlled light. Whilst there is a place for PIR controlled lighting, many domestic versions on sale do not operate well in the hostile external environment and therefore may not function as well as expected.
Energy Conservation
Energy supply companies have an obligation to contribute energy savings to national targets over the 3 years to 2005. This may include free or discounted high efficiency low energy light bulbs and it is therefore worth investigating with supply companies whether or not this is available in your area. Neighbourhood Watch schemes could be involved to facilitate local distribution of low energy lights for both internal and external use.
How to use PIRs properly
The Institute of Lighting Engineers have produced an easy-to-understand guide to security lighting, balancing the pros and cons of both PIR halogen lighting and dusk-to-dawn low wattage lighting. They also outline how to fit a PIR light to avoid or mitigate some of the negative factors outlines above.
Download the ILE guide to Domestic Security Lighting from the ILE website
Last update: Wednesday, September 13, 2006