Efficient Outdoor Security Lights

<i> Dulley is a Cincinnati-based engineering consultant</i>

QUESTION: There were several break-ins in my neighborhood. I want to install outdoor security lights, but they are so expensive to operate. Are there any bright lights that don’t use a lot of electricity?

ANSWER: Lighting the exterior of your house, especially the back yard, is one of the best methods to deter a thief. There are new bright super-efficient outdoor lights (high intensity discharge--HID) that you can install yourself. They use only a couple of cents worth of electricity per night.

High-pressure sodium lights are the most efficient HID light commonly used for homes. One small 35-watt high-pressure sodium floodlight is brighter than five standard 40-watt bulbs combined.

Although these fixtures and bulbs are more expensive initially, they quickly pay back their higher cost in lower electric bills. The bulbs last 20,000 hours as compared to less than a 1,000 hours for standard floodlights, so there is savings in bulb replacement costs too.


There are many new HID light styles designed for home use. These fixtures are now smaller and more attractive. You can buy antique-designer light posts, contemporary bollard lights for use near a deck or pool, wall floodlights, in-ground lights, etc., many with high-pressure sodium bulbs.

If you are going to illuminate a large area and are not concerned about the light’s color rendition quality, low-pressure sodium bulbs use even less electricity. Generally, you will only find these at commercial electrical outlets.

The most common HID floodlights sold at home centers are mercury vapor. These are twice as efficient as standard floodlights, but still much less efficient than high-pressure sodium lights.

Motion-sensing lights are one of the best crime deterrents and use the least amount of electricity. They can sense motion as far away as 60 feet and you can adjust the on-time from one minute to 30 minutes.

A floodlight’s switching on usually scares a thief away. Some models have an interior module into which you can plug lamps. When the motion-sensing floodlight comes on, it also switches on the interior lamps. Even when you are away at night, it appears that someone inside switched on the lights.

In my own home, I use solar-powered motion-sensing floodlights. These need no wiring, so they are ideal for back yard or storage shed locations. With powerful internal batteries, they will switch on 120 times on just one day’s charge from the sun.

Write for Utility Bills Update No. 891 listing 17 manufacturers of high-efficiency outdoor security and decorative lights, styles, bulb types, motion-sensing 110-volt and solar floodlights, and a cost-to-operate chart. Please include $2 handling fee--cash or check--to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

Itchy Insulation May Be Thing of the Past


Q: I want to add insulation batts to my attic. Fiberglass is easy to use, but it irritates my skin. What other insulation options are there?

A: Fiberglass insulation batts can be itchy if you do not dress properly. You should wear heavy coveralls and gloves. Put rubber bands around the wrist area of the coveralls over the gloves to seal the arms as well as possible. Wear a breathing face mask too.

Blown-in rock wool or cellulose is another effective insulation option. If you can wait several months, a Canadian company is developing a non-itchy fiberglass-like batt insulation made from recycled plastic bottles.

How to Help Reduce the Greenhouse Effect


Q: I want to help reduce the greenhouse effect. About how much carbon dioxide (greenhouse gas) is produced per person each year?

A: The majority of the carbon dioxide gas (CO2) produced is from the burning of fossil fuels to produce energy. On average more than 40,000 pounds of CO2 is released into the air per year for each U.S. citizen.

To run a typical average-efficiency refrigerator for one year, a coal-fired power plant produces more than 2,000 pounds of CO2. Switching to a new high-efficiency refrigerator can reduce this amount by about 600 pounds.

A general rule of thumb is that for each kilowatt-hour of electricity saved, about 1.5 to 2 pounds of CO2 is eliminated from entering the atmosphere.


Extra Nails, Fasteners Harm Insulation Value

Q: When I build an addition on to my home, I plan to use rigid foam insulated sheathing on the outside of the wall studs. Will it harm the efficiency to use more nails and fasteners for a stronger wall?

A: Adding more nails and metal fasteners than recommended by the manufacturer does not produce a better wall. In fact, it decreases the effectiveness of the rigid foam insulation. Tests show that using just the recommended number of nails and fasteners (on eight-inch centers) reduces the insulation value by 20%.