Auto-Off Switches – The Skinny

When traveling and staying in hotels these days, you are beginning to see more and more auto-on/off light switches.   Here in the U.S., some hotels have lobby restrooms with auto-on/off motion sensor switches.  In Europe, in most updated hotels you have to insert your hotel key card into a slot by your room door to activate the power in your hotel room. So that whenever you leave the room and pull the key card, all the lights automatically switch off – pretty nifty.   I was once in London at a business meeting in a conference room with a motion sensor light switch, it was an incredibly low energy get-together, no one was moving or showing much life, (my team was jet-lagged) and the lights kept switching off.  As you might suspect, nothing much came from that meeting.

These same motion sensors and timer switches are now available for residential installation, so Green Blizzard decided to install and sample a few to see how they worked and to see if we could further squeeze energy savings and smartly reduce our carbon footprint.

Green Blizzard purchased two types of auto-off switches.

A Vacancy Sensor Auto Off Light Switch a wall switch with a night light that automatically turns off if there is no movement in the room for 30 minutes ($35.99),

A Time-Based Auto Off Light Switch with an assortment of different fixed timed buttons (5 minutes, 10 minutes,…1 hour, or if you prefer hourly incremental 1,2,..8) for use in a closets, bathrooms, basements, garages, recreation rooms.(ranging from $25-$28). 

Installation was a snap – no different than installing a basic switch and it readily fitted into the standard wall box.

We wanted to figure our break-even,…how long it would take to recover our investment from these switches.  How many needless bulbs burning hours we’d have to avoid to recover the investments.

Basically, if you use inefficient bulbs and are careless about turning off un-used lights, you can recover the switch cost in about a year.  Otherwise, depending on your electricity kilowatt costs, the type of bulbs, and the hours you figure you’ll save, …it will definitely be a few years until you start seeing some net savings –  because the individual switches cost so much and electricity is cheap.  Rule of thumb, the less efficient the bulb, the higher your rates, and larger the average hours of wasteful burning avoided – the sooner you’ll see net savings.

If you’re considering converting to these smarter switches to reduce your carbon footprint, here are some ideal conditions that will make this a smarter investment and a quicker return:

  • You have a large or young family with plenty of inside activity;
  • You live with few forgetful housemates or are forgetful yourself about regularly switching off the lights;
  • Your co-habitants don’t care about saving money, greener living, or are too busy to be bothered:
  • In the mornings, your co-habitants suddenly leave as if there’s a fire.

Green Blizzard calculated the electric savings and carbon footprint reduction as follows with the Help of Mr. Electricity:

  • Wattage of bulbs impacted by the switch 60 watts / 1000  =  kilowatts  (*)
  • Cost of Kilowatt from your provider  (i.e. Pepco -DC Metro area is $0.19 kwt hour)
  • Cost to Operate These Bulbs for One Hour – 1.5 cents
  • Operating Hours Avoided Per Day by auto-off = 1 hour
  • Savings Per Year = $4.50
  • Years To Breakeven (6 years for one switch, 8 years for the other)

(*) Our calculations were based on our already installed low wattage CFLs throughout our headquarters.  If you still use the old fashioned incandescent bulbs, you’ll be in the money very soon.

Give it a try in that high usage, frequently “forgot to turn off the lights” areas of your home or office and start realizing savings and carbon footprint reduction now, rather than later.   Green Blizzard gives this carbon reduction opportunity, two green footprints.


About the author

Moose Mosely

Moose, (yes, that's his everyday name - at least as far as we know), writes about all sorts of green living insights. Every minute, every decision we make in our lives has some impact to our personal carbon footprint, and Moose is there to share some insights on its impact and relevance and suggests healthier alternatives.