I'd like to connect a timer to my new instant hot water dispenser. The installation instructions mention not to use an extension cord, but I'd like to make the timer accessible under the cabinet so I can adjust it.

My plan had been to run a short heavy duty extension cord from behind the dishwasher to under the sink with a timer in between. Is there anything wrong with this?

  • Frankly, it's probably not worth it. The tiny amount of electricity saved would be easily surpassed by the cost of a timer.
    – longneck
    Dec 10, 2013 at 20:29
  • @longneck thanks, but I wasn't necessarily looking for advice on the economics. It actually costs about $40/yr to run at temperature. Dec 10, 2013 at 21:41
  • 1
    An extension cord is not NEC approved for "permanent installations". As a homeowner you might not be bound to abide by the NEC, but if a fire resulted, your insurance company might find you negligent for creating an unsafe situation -- especially when the instructions for the device say not to use it with an extension cord.
    – Johnny
    Dec 10, 2013 at 23:42
  • 3
    You might not save as much energy as you think you will since the water will cool while the timer is off and you'll have to heat it up again when you turn it back on. If you want to save energy and only want hot water for your morning coffee, an electric kettle that you fill yourself would be more energy efficient.
    – Johnny
    Dec 10, 2013 at 23:49
  • Most timers aren't designed to take the load a heating element would need. You'll probably have to hardwire this with the timer turning on/off a relay on a separate circuit set up for the heater.
    – DA01
    Dec 12, 2013 at 8:06

2 Answers 2


You need to determine the maximum current (amperage) your water dispenser will draw, then verify that both the extension cord and the timer can each handle that current as as sustained load.

  • Don't you mean max amperage?
    – Ethereal
    Dec 16, 2013 at 16:09
  • I had considered that in my originally but chose watts since most appliances only list wattage and standard (US) wall outlets are all at a fixed 115 voltage. Your assertion, however, is more correct especially when considering non-US, or higher amperage outlets.
    – virtualxtc
    Dec 16, 2013 at 19:18
  • 1
    edited -- decided to take your advice.
    – virtualxtc
    Dec 16, 2013 at 19:23

Yes. I asked insinkerator, “ Yes, you can put a timer. That should not be a problem.”

In my house we don’t use hot water from 10pm to 7am. You can test that it would be worth it by trying a kill-a-watt meter in line. And seeing that it makes $ sense to turn off and the energy to reheat from cool every morning (which takes like 15 minutes). Run the meter from the off time (10pm) to the on time (7am) and check the amount of electricity it takes. Do this a few times to get a reliable number. Then compare that to using the timer and include the energy used at 7am to get back to “hot”. But yes you can do it.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.