Light Bulbs

Light bulbs – there are so many type of light bulbs that it is impossible for me to address. But I will discuss a bit about the five most common around your house.

The original light bulb (1) was incandescent. It ran a lot of power through a small wire, called a filament. That filament, in some sense, isn’t rated for that much power, so the reaction is to heat up and create visible light. The bulb contains a gas which allows the filament to light up without breaking the circuit. If the glass bulb were damaged, gas would escape, and the filament would break. In simple terms, gas is the only difference between a fuse and an incandescent light bulb. The light bulb with gas emits light, the light bulb without gas will heat the wire filament until it breaks, just as a fuse breaks when too much power travels through it. Of course, house fuses are generally not designed to break with the amount of power required to turn on a single light bulb – so there are differences. Incandescent bulbs were rated in watts and are inefficient because energy is lost in the form of heat.

Secondly (2): fluorescent bulbs, the long skinny tube bulbs seen in grocery stores, hardware stores, garages, kitchens, and so on. They have a filament on one end of the bulb and another filament on the other end of the bulb, but no solid material connects one end to the other. Instead, there is gas in the middle of the tube that is excited by the electricity and so it illuminates to create visible light. There is a lot more going on with these light fixtures than just the bulb, they require a ballast and a starter – but that is enough about these bulbs.

Third (3) and related, we have CFL bulbs or compact fluorescent light bulbs – these are commonly the swirling light bulbs that were more efficient than incandescent bulbs, losing less energy to heat. They are often rated in light output relative to incandescent bulb wattage, or they can be rated in lumens – an independent measure of light itself. Essentially, they are fluorescent bulbs that have been wrapped in a circle and all the required electronics are built into the base, so you can install them anywhere an incandescent bulb was without adding the ballast or starter.

Fourth (4), we have LED or light emitting diodes. LEDs were around as indicator lights for computers and electronics for a long time, but in past decades we discovered that the technology can be applied to illuminate rooms in a much more efficient way as they lose less energy to heat output. They come in many applications, the simplest is a bulb that can replace incandescent or CFL bulbs with all the electronic controls built in. LED tube bulbs can also replace fluorescent tube bulbs, but this takes more consideration as some were rated to work with the existing fixture’s ballast and some were not – and mixing them caused explosive problems. They are often rated in light output relative to incandescent bulb wattage, or they can be rated in lumens – an independent measure of light itself.

Fifth (5), and least commonly applied in homes, are high pressure sodium bulbs. These tend to be seen on garages, workshops, pole lights, high beam car head lamps, and other applications. They are similar to fluorescent bulbs in that they have electrodes at either end of the bulb and a gas between them. It is a different gas, and as the name suggests, it is under more pressure than fluorescent bulbs. These bulbs are fragile and should not be touched directly by human skin, because they tend to heat up a lot. Any oil left behind can overheat the bulb. These also require a ballast and starter. High pressure sodium bulbs put out a lot of lumens and are more efficient than incandescent.

Consult with an electrician or lighting specialist before making changes, some utility companies may even offer rebates for upgrades through an approved contractor.

Too long, didn’t read version: light bulbs light up your house, there are a lot of varieties, some are old and some are neat.

-Marshall Tramp, CPI, RMP


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Marshall Tramp, CPI, RMP
Author: Marshall Tramp, CPI, RMP
Top Notch Inspection Services llc
Serving Eastern Washington & Northern Idaho