Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've been happily using my ADSL wireless router for five years, only switching it on when I use it which is typically in the evenings and at weekends. Over the past fews weeks I had a dramatic drop in speed and logged a fault with my ISP.

enter image description here

They said that there was an (IP) profile mismatch on my account which they have rectified and early indications are that the performance has been returned to normal.

However, they have advised me that the router should be constantly plugged in to the telephone socket (it is) and left switched on. I'm not keen on leaving it on all of the time, mainly from an environmental point of view (every little helps, right?), but also to stop it getting too hot.

Can turning a router off when not in use degrade the performance of the broadband connection?

share|improve this question
Routers are certainly designed to be left on 24/7, so it shouldn't get too hot if it's properly ventilated. I don't leave mine on (partly to force the kids off their iPods from time to time!) 24/7 and haven't experienced significant speed problems. I have noticed a few occasions where I've had to do a hard reset (turn it off and back on again) on the router to fix domain name resolution issues etc. This isn't just on mine either. – ChrisF Jul 15 '10 at 20:58
Most electronic equipment get hot and use maximum power when it's actively working, so it shouldn't make much of a difference to turn it off when it's not being used. Anyway, I don't understand why you care about the device getting hot. – alfplayer Jul 15 '10 at 21:23
As far as I am aware - only Fibre routers need to be left running 24/7 due to DML - ADSL routers do not use DML - So can be turned off and on at will, without it affecting the connection speed.. – user434463 Apr 4 '15 at 8:25
@alfplayer have you never had a device that you thought was running too hot for its own good? devices have ventilation to reduce it.. but sometimes there can be issues with it. e.g. I had a router whose ventilation was on the bottom. I would turn it upside down 'cos maybe it cools better that way. – barlop Apr 4 '15 at 8:43
up vote 1 down vote accepted

I think you are experiencing the ISP being rather too clever.

(Some?) ISPs keep checking with all the modems to which they are connected to make sure the connection is running at "optimum speed".

If you turn your modem off, the ISP thinks that it is not working correctly (or the line cannot handle such a high speed as what it is supposedly connected at) when it checks the line, and, to make it run better, turns the speed down.

share|improve this answer
My ISP has since advised that I disconnect the router via its admin pages before physically powering off the device. Apparently just turning it off logs an error at their end. – John Topley Jul 17 '10 at 17:07

I'm not sure why your service was slow, but it's possible that not having the router on all the time to talk to the service provider caused an error on their side.

I would say leave it on. Routers don't use up much power. They use less than 1/10th of the power a typical computer uses while it's running. It doesn't amount to much.

Here's some data:

"My cable modem uses 7 watts, my D-Link DI-604 router uses 4.5 watts, and my Motorola phone box for use with Vonage uses 2 watts while idle (3 when I'm on the phone)." Link

compared to...

Washer: 350 W - 500 W Dryer: 1800 W - 5000 W Computer with monitor: 100 W - 400 W Large TV: 100 Link

As for turning an electronic device on and off, they can experience thermal stress on the components, but most devices are rather robust these days.

Overall, I'd say you'd better off leaving your router on. According to online reviews (I sifted through 50+), most people have better luck leaving their routers on. Though I only saw a handful of complaints about turning it off everyday.

share|improve this answer

I always turned my router off when not in use but following speed problems I have recently been advised by my ISP to leave the router on 24/7. I haven't noticed any significant warming when touching the router (5days now) I have run a speed test at regular intervals ( slight ups and downs) nothing to panic about. I think the advise from the ISP must be right particularly as they provided the router misinformation would be costly to them if only in customer disatisfaction.

share|improve this answer

Problems are caused on the modem level when it over heats, you can solve the entire problem of this just by ensuring good ventilation of the device. The only other problem it is prone to is capacitors 'frying' (they actually harden), which is quite common as they are only rated for n hours. If you keep the device cool you will maximize it's life. No, turning it off won't do anything other than maybe let the caps run for a longer time... but if you keep them in a warm place, they're hardening anyway.

Problems can happen "down the line" meaning your phone line between you and the ISP can get messed up (again, they're only rated for so long, then they degrade and get replaced). This is also common.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

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