Lighting is one of the highest energy users in the average home. In 2007, lighting contributed to 11% of the average US household energy costs.
As it happens, changing your light bulbs is a easy way to save energy and money. An energy efficient light bulb like a CFL or LED can easily save you 70% or more.
Use the tool on the right to estimate the cost of your lighting or check out what your savings might be if you switched to an energy efficient light bulb.
If you aren't sure what your electricity price is, just check your most recent bill or go to the energy prices page (click this link or use the navigation bar on the left)
Types of Light Bulbs
The types of light bulbs can be generally split into 4 categories:
Incandescent bulbs are the traditional bulbs you are most familiar with (pictured to the right). They work by using electricity to heat a tungsten filament in the bulb until it glows. These are not considered an energy efficient light bulb.
These bulbs are very inefficient as the majority of the electricity consumed by the bulb is converted to heat not light. This is why these bulbs are typically warm / hot to the touch. These bulbs typically last 700-1000 hours and cost around $0.50.
The halogen bulb is similar to the incandescent bulb except that the tungsten filament is inside a tube containing halogen gas. Halogen bulbs are slightly more efficient than incandescent bulbs and last longer.
The major disadvantage of these bulbs are that they can become extremely hot and are fairly expensive. If using these bulbs, keep flammable items away from the bulb and be careful not to touch the bulb.
Check out this video. It shows how incandescent bulbs are made.
Fluorescent / Compact Fluorescent (CFL)
Fluorescent Bulbs have been around for many years in the form of the long tubes you see in offices and stores (pictured to the right).
These bulbs pass a current through a tube filled with argon gas and mercury. This produces ultraviolet radiation that reacts with a phosphorous coating causing it to emit light. Fluorescent bulbs require a component called a ballast which regulates the voltage to the proper levels. (note: the humming you hear sometimes comes from a magnetic ballast)
Compared to the incandescent bulb, fluorescent bulbs are much more efficient, emit less heat and last longer.
Compact Fluorescent (CFL) bulbs have been around since the 1990s. These bulbs screw into typical light socket (check with a store rep. when purchasing to see if you have the right size). This energy efficient light bulb is your best value for your money.
A 13 watt CFL bulb puts out the same approximate amount of light (lumens) as a 60 watt incandescent light bulb and much less heat (which is an additional benefit in the summer when you are trying to cool your home).
A CFL lasts up to 10,000 hours (incandescent - 1000 hours) and costs $2-4 (incandescent - $0.50).
Can CFL bulbs put out soft light like incandescents?
There is a perception that CFLs only put out the bright white light found in offices. This is not the case. There are a few options when purchasing CFLs. Soft light bulbs are available; these bulbs match the light colour of incandescent bulbs and provide a nice relaxing atmosphere. Other options include bright white (good for offices and bathrooms) and daylight.
What about the mercury in the bulbs?
It is true that there is mercury in all CFL bulbs and mercury is a toxic element. All CFL bulbs must contain less than 5 mg of mercury, and most contain under 1.5 mg.
First, the mercury inside the bulb is not an issue at all if the bulb doesn't break. After all, most thermostats contain approximately 3000 mg of mercury and the battery in your watch likely contains around 25 mg of mercury (not to mention old thermometers).
Second, if the bulb does break, experts say that the likely exposure is less than you are exposed to when you eat a can of Albacore Tuna.
If a bulb breaks, to be safe use gloves to clean up the mess and seal the broken parts in a plastic bag and throw it out.
If you are concerned with this issue, you can buy CFLs with a protective cover, which lets no mercury escape in the case of breakage. Use these bulbs in locations that your children can get to ease your concerns.
Some people are concerned with the effect of emitting mercury into the air. The bottom line here is that more mercury is put into the air by power plants supplying electricity to your old incandescent bulbs than is found in a CFL bulb in the first place. Also, stores like Home Depot allow you to bring in your "spent" CFLs to be recycled (no mercury emitted into the environment).
Check out this video. It shows how CFL bulbs are made.
LED (light emitting diodes) bulbs
LED bulbs have been sold commercially for only a short period of time. These bulbs have no filament. One bulb will generally have many LEDs (see picture to the right).
While being a highly energy efficient light bulb, LED bulbs are still very expensive ($50). They can last up to 25,000 hours.
LED bulbs emit light in only one direction so they do not evenly light up a room without putting many lights in the room.
In addition, most bulbs only put out the bright white light that is not desirable in most homes (good for offices and bathrooms).
As this technology is relatively new, we can expect these issues to be resolved over time; the price is bound to drop as well over time.
HID bulbs are typically used in applications where one bulb is required to put out a lot of light. Examples would be in gymnasiums, street lighting, warehouses, and production lighting.
These bulbs are usually very expensive.
HID lamps usually have ballasts.
HID lamps usually take a while to warm up before the bulb emits bright light. Sometimes if you turn the light off, you have to wait before turning it back on.
Low Pressure Sodium Lamps have the highest efficiency of all bulbs but put out a yellowish light. These are common in greenhouses and parking garages.
Metal Halide Lamps are not as efficient as sodium lamps but they put out a brighter, white light. These are common in gymnasiums and auditoriums.
Why not check out the page on Low Flow Shower Heads. Changing a shower head is probably the easiest way to save a lot of money (not unlike switching your light bulbs).