There is existing standard technology using a mechanical switch designed for just this purpose and made by a standard electrical equipment company which has been in use since the 1950s, if not earlier. Proven, simple, cheap, 100% code-compliant.
The OP already has the wiring, socket, etc. all completed during construction of the house.
And now folks want to add something involving a computer and RF communication to turn on a common lightbulb.
What the heck are we turning into?? Next we’ll want an app for that. And a social media feed so we can all see (and comment on) whether the lightbulb *wants *to change.
Sheesh!
Back to the OP: Why a 10-watt LED versus a 100 watt plain old incandescent? The thing runs for a couple minutes per day. You’ll die of old age or sell the house long before you earn back the savings in electricity. Not to mention the flaky reliability of current LEDs.
My problem with the 100 watt incandescent is they are difficult to find, are cheaply made, when you do find them, and tend to fail at a higher rate than quality LEDs. The pantry is of main use of my wife, who really doesn’t like CFL. She says she can see them flicker. If I had a choice between CFL and incandescent, it would be an incandescent. I’m not trying to save money, I am trying to make my wife happy (call me crazy).
I am pretty sure the on-off cycling of the water heater, or merely the heating of the pipe when hot water is run, would trigger a motion sensor. While static heat sources may not trigger it, I don’t think it could tell the difference between a moving heat source and a source heating up. My understanding is they are looking for a change is the heat signature, which would trigger it. I am not interested in running a bunch of tests when there is a safe, reliable, off-the-shelf solution to the problem.
I thank all for their suggestions, and some may be considered for other problems, but for this application, I believe the doorjamb switch is the best solution for me.
My point was dissing unnecessary complexity, not advocating Luddism. I like gadgets as much as the next guy.
If he was trying to install a light where there was no power and no wiring then something like a motion-sensing battery-powered LED light would be just the ticket. If he had a light socket but no switch where he wanted one, then something like an X-10 socket & remote switch would be completely reasonable.
He wanted a conventional 120V light switch triggered by the door opening. So I offered him a conventional 120V light switch designed to be triggered by a door opening. Seemed pretty sensible to me.
Your understanding is wrong.
Motion sensors look for heat crossing rows of detectors, making them insensitive to non-moving heat sources, but do whatever you think is best.
FYI, at least in my case, I was just bringing up the Z-Wave alternative for the benefit of others who might be reading the thread. For some people, the wireless alternative works better than wiring in a new circuit. It can literally be done by screwing in a new light bulb, screwing in the two parts of the contact switch, and poking a few buttons on a controller.
More complicated under the covers, but the installation may be easier for some.
OK, but It seems like the door jam switch is what is unnecessary complex. Installing a door jam switch, which I assume means creating some sort of cutout, along with wiring it seems like a hell of a lot of trouble and work and time when a simple screw in motion sensor is quick, cheap, easy and effective, and again tape (or paint, nail polish) can be used to cover the portion that is facing the water heater. Problem solved in about a minute and under $20.
that door jamb switch has wire leads, those need to be attached to. that is more complexity because they need to be enclosed .
also how is the door used? if the door is always closed, except when the room is in use, then the light is off except when the room is in use with a jamb switch. if the door is always or often left open then another switching scheme would be needed.
if the door is left open then kitchen activity will trigger a ceiling mounted motion sensor.
physical layout and room/door usage have to be considered in finding a solution. there may be an electrical/physical and/or cultural solution that considered.