There are different kinds of lights; they are incandescent, fluorescent, halogen and low voltage. Incandescent light bulbs are the most common. They last about 1000 hours and in the average home you will change them every six months. They are very inexpensive to buy. A 40-watt bulb in most homes, cost about $12. /yr. to operate. If you had ten 40-watt bulbs it would cost you $120. /yr. If they were 100 watt bulbs it would cost around $300. /yr. This exemplifies the difference in wattage and the number of bulbs and how it affects your electric bill.
Compact Fluorescent Lights uses neon gas and is larger in size than an incandescent bulb. They cost approximately 1/4th to operate than an incandescent bulb. A 25-watt fluorescent bulb gives off the same amount of light or lumens as a 100-watt incandescent bulb. So in the above example with ten 100-watt bulbs that cost $300. /yr to operate. An equal amount of lighting with fluorescent would cost only $75. /yr. This is why in department stores you only see fluorescent lighting. Other advantages with fluorescent lighting are their operating temperature is much lower than incandescent and halogen and they last 10000 hours.
If you ever touched an incandescent bulb after it was on for a few minutes you would see that it is quite hot. A fluorescent bulb you could touch. In areas where you use a lot of lighting such as a kitchen, the operating temperature of the type of lighting will play a major role when cooling this area. A fluorescent bulb will last ten times longer than an incandescent and two and a half times longer than a halogen. In other words if you change your incandescent bulb every six months, you would change a fluorescent bulb every five years. The disadvantages with fluorescent lighting are the size of the bulb and the cost to purchase, especially compact fluorescent bulbs. Halogen lights uses about 2/3rd amount of watts to give off the same amount of lumens or light that an incandescent light.
It lasts 4000 hours or four times longer than an incandescent. Its operating temperature is hotter than an incandescent and much hotter than a fluorescent. Its cost to purchase is more than an incandescent but less than a compact fluorescent. All this makes halogen lighting ideal for outdoor lighting. Unlike a fluorescent light that has a minimum operating temperature, an incandescent and halogen does not. An example of this is a front porch light that is used to illuminate the steps at night when guest arrives at your home.
If a compact fluorescent is used there on a cold winter night, the light will not illuminate fast enough for your guest to see the steps clearly. Though the operating temperature for fluorescent lights is low, the cold temperature will affect its operation. This is not true with incandescent and halogen. Though halogen bulbs cost more than incandescent, the lower cost of operation and longevity of the halogen over the incandescent makes the halogen the ideal choice for this application. Low voltage lighting will be the future lighting in our homes.
Today it is primarily used for outdoor lighting that illuminates walkways and driveways. You will see some indoors low voltage lighting used today but they are fanciful lights and are very expensive. The advances in technology with diffusers and lenses along with fixture for low voltage lighting have improved tremendously over the last decade. The home of the future will have photovoltaic roofing shingle and/or a wind funnel that would resemble a brick chimney on the side of your home. It would use a turbine inside it that turns due to air movement inside because of the temperature difference from the top to the bottom. This technology will work very well with low voltage lighting.
In the future this application will be unsurpassed as far as cost of operation, longevity and flexibility. I am surprised that no one has tried this in a commercial application. There are three categories for uses of lighting; they are general, task and aesthetic. General lighting is the most commonly used lighting in homes today. Examples of this is the light in the hallway, the light you turn on in the kitchen just to get a glass of water or the light in the laundry room.
Task lighting are the lights you use for preparing food, cooking, washing dishes or the lamp you use to read. Aesthetic lighting are the lights you use to highlight areas of your home like a vaulted ceiling to take away shadows created by general lighting, a picture on the wall or to set a mood in the room. The problem with lighting is when the wrong lighting is used. An example of this is using general lighting for a task.
Let's say you have two general lighting fixtures in your kitchen at either end of the kitchen. They are both on the ceiling of either side of the sink and behind you when you are there. Both fixtures use two sixty watt bulbs for a total of 240 watts (60 x 4). To avoid casting shadows over the sink when washing dishes you have to turn on both fixtures. If you installed a single 100 watt recess light fixture above the sink, it would be less than half the cost of operation and a 25 watt fluorescent would be about one-tenth. This exemplifies the use of general lighting for task lighting. An example of task lighting used for general lighting is using recess lighting as general lighting in the kitchen discussed earlier. General lighting fixtures diffuse light around a large area, whereas task lighting focus the light in a small area.
To illuminate the entire kitchen you need a lot of 100-watt bulbs and fixtures with task lighting. Probably 1000 watts to equal the general lights the 240 watts of general fixture and 60 watts for fluorescent. The cost of operation is dramatic.
The worst person to ask for lighting advice is an electrical contractor. He makes his money in the number of fixtures he installs. It takes five times more task lighting fixtures to provide general lighting for a specific area than one general lighting fixture. Another example is aesthetic lighting use also for general lighting that is task lighting fixtures. Recess lighting used in a dining room that has a dimmer and the room is used once a week for quest. This is a good application of lighting. The reason for this is the hours of operation. Apply this lighting system to a family room that is used every night for several hours and it is not cost effective. When choosing lighting for a room with a sales person or electrical contractor, the best advice is to keep asking for options.
There are tables these people use that illustrate the amount of lumens a room require. The different sizes, type and wattage are given. An example is the number of recessed light fixtures required to illuminate the entire room and how far apart they should be is illustrated in those tables.
The best rule with lighting is less is better, but is not if it does not do what you want. One way to save energy is to better control the use of lights. Like a motion detector that turns on the lights in a garage, basement or stairwell and goes off automatically when no-one is there.