Autosensing Light switches?

Question

I always wanted to do a feasibility study about Autosensing light switches.

I see lights on at night, which I think could be eliminated with autosensing switches, instead of the dusk till dawn switch sensor.

The cost up front is what would matter the most. That and maintenance.

How long would it take to recoup the cost of autosensing switches as opposed to leaving the light on all night?

Lets say a standard 100W bulb that goes on and dusk and stays on till dawn. Equivalent to 6 months.
356/2 = 178 days.
178 x 24 = 4272 hours.
Also, I know that surge accounts for the lifetime of a bulb, but how much I do not know.

I think apartment complex and large building could benefit greatly from this.

Answer 1

Yes it would pay for itself. At 10 cents per kwh with that bulb being on for 427.5 kwh you would save about $42. You can get the autosensing switch for much less than that. It is a good deal.

Answer 2

I have some X 10 autosensors. They are relatively cheap, and have proven reliable. They will only work with incandescent bulbs though.

From your electric bill you can figure the annual cost per bulb with autosensing. Where I live it would be about $43. That would more than pay for itself within a year, particularly if you switch to the new small fluorescent bulbs.

Answer 3

Check out your nearest Home Depot or Lowes.

They have light switches with built in motion detectors. They just replace an existing light switch on a wall.

Will be a simple calculation to see how many watt hours would need to be saved to make up the cost.

Answer 4

You can buy them at Lowe's and Home Depot and just about anywhere else right now.