Light switches

As part of a remodeling project, I had the opportunity to help tear out the interior walls in a hundred-year-old house. You take a hammer and start by whacking through the plaster. There's about a dozen layers of paint, and then the plaster has hair and all kinds of other stuff mixed in. The plaster was slathered on wooden lath strips. So you strip out all the paint, plaster and lath and throw it in the wheelbarrow.

Once you break through all of that, you find that the walls are insulated with bricks. Yes, bricks. The outside walls are wooden siding, but between the plaster and the siding is a layer of roughly-mortared brick.

The most amazing part, however, was finding the pipes. All kinds of pipes, not for water but for gas. Yes, this house once had gas lighting in all the rooms, and the pipes are still there.

Today we look at all this and laugh. Horsehair??? Lath??? Bricks - for insulation??? Gas pipes??? Using gas for lighting seems amazingly dangerous.

I relate this story to show how easy it is to look at older technology and see the obvious problems with it. Troweling plaster on by hand was time-consuming. Mixing it with horse hair was gross. Insulating with bricks not only took a lot of time, but it did not work particularly well. And lighting with gas presented a host of hazards, from explosions to fires to asphyxiation.

Today's light switches are not quite that bad, but I think that in 20 years people will look at them with the same amusement we reserve for gas lighting.

The most amazing thing about a light switch is that it is totally, completely passive and dumb. What that means is:

• If you lie down in bed and happen to forget to turn off the light, you have to get up again to flip the switch.
  
  
• If you leave the room and forget to flip the switch, the light stays on regardless.
  
  
• If you turn the light on at night but then the sun comes up 8 hours later and fills the room with sunshine, the light remains on despite the fact that it is no longer needed.

Then there is the fact that the light switch clamps across 14-gauge romex able to carry 15 amps, despite the fact that the light it controls only needs half an amp for an incandescent bulb, and only a tenth of an amp for an LED bulb. The amount of copper wasted in this way is astronomical.

Obviously what you would prefer is an intelligent switch, probably built into the light itself rather than the wall, that can understand your voice as well as the conditions in the room. If you walk into the room at night, the light turns on automatically. If you lie down and say "light off", it turns off. And so on.

The next time you get up out of your chair and walk out of your way to flip the light switch on the wall, think about how primitive a system this is. People will look back at this period in human history with the same quaint feeling that we have when we think about gas lights.