should i switch wifi box off every night

GlynD

I switch my wifi router off and leave the BT modem on. I do this because I am concerned that, even though my network is secure, someone will hack into it and use it for nefarious purposes. There is a precedent for this. In Scotland a notorious !!!!!phile ring were using the signals of adjacent wifi routers to access whatever it is they access. I know the signal strength is finite but I still worry.

WTFH

Well, I'm not sure about your routers, but the max power output of the power supply of my BT home hub is 150mA at 6v.last time I did physics, P=VxI.
Max power is therefore 0.9w

If you have an inefficient one, or one that defies the laws of physics, then it's entirely possible it uses 4x that power, or even 10x, but check your power supply before guessing the amount a device is using.

esuhl

My old Netgear DG835G router has a DC power adapter rated at 1A at 15V... So the maximum supplied power would be 15W.

This article, "Analysis of Power Consumption in Consumer ADSL modems" suggests that the DG824G uses (roughly) 5.0 to 5.3W in actual use.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.186.360&rep=rep1&type=pdf

5W = 0.005kW
24h in a day X 0.005kW = 0.12kWh per day
365 days in a year X 0.12kWh per day = 43.8kWh per year.

At a cost of, say, 13p per kWh, that's a total running cost of £5.69 a year if the router is left on all the time.

EDIT: Just thought I'd re-iterate that this is quite an old router -- a good several (close to 10) years old. It's possible that newer routers would be more energy efficient.

Norman_Castle

I do hope you have a very sophisticated (and expensive) "power meter" - if you have a bog standard domestic one they are useless when reading small (less than 100W-ish) amounts of power

Cable clip monitors are inaccurate at low power. Plug in monitors are apparently accurate to within 1-2%.
If anyone has an industry standard, calibrated monitor and a cheapo plug in monitor I would be interested in exactly how accurate they are.

My Plusnet/Thompson router uses 6.7w which appears average according to the above tests.

Norman_Castle

WTFH wrote: »

Well, I'm not sure about your routers, but the max power output of the power supply of my BT home hub is 150mA at 6v.last time I did physics, P=VxI.
Max power is therefore 0.9w

If you have an inefficient one, or one that defies the laws of physics, then it's entirely possible it uses 4x that power, or even 10x, but check your power supply before guessing the amount a device is using.

Would the power supply use energy converting 240v to 6v?.

spud17

I use a Netgear DG834GT with custom firmware.

The plug through power meter (Maplins) shows it using around 6 W. That's broadly in line with esuhl's figures.

As an aside, my TrendNet 5 port gigabit switch used 0.03 kWh in 7 days, this has built in power saving/management, which even adjusts power according to cable length.

esuhl

Norman_Castle wrote: »

Would the power supply use energy converting 240v to 6v?.

The UK uses 230V (nominally) now, but to answer your question, "yes" -- no circuit is 100% efficient.

This quote from Wikipedia suggests that domestic power adapters are likely to be around 20% to 90% efficient:

Considering the total efficiency of power supplies for small electronic equipment, the older mains-frequency linear transformer-based power supply was found in a 2002 report to have efficiencies from 20–75%, and have considerable energy loss even when powered up but not supplying power. Switched-mode power supplies (SMPSs) are much more efficient; a good design can be 80–90% efficient, and is also much smaller and lighter.

https://en.wikipedia.org/wiki/AC_adapter#Efficiency

WTFH

Norman_Castle wrote: »

Would the power supply use energy converting 240v to 6v?.

Yes it will. As has been said, an old transformer might be between 20 and 75% efficient. At 20% efficiency, 0.9W output would require 4.5W input. A modern one running at 90% would be 1W input. But then again, the 0.9W I quoted was the maximum output of the transformer, so the real output for normal usage would be less than that.

amorphix

savingjenny wrote: »

I always switch the wifi box off every night and switch it on when I want it next. Most days but sometimes it isn't switched on for a few days.

My son has just said that I don't need to do do this any more as it uses very little electricity and it is better to leave the line 'open' all the time.

Is he right? I use BT for the internet if that makes a difference.

It depends on your reasons for wanting to switch it off.

Some people who are security paranoid feel safer switching it off, while others, think it may save electricity and/or bandwidth.

In reality, it poses no security risk leaving it on, if you have a firewall and/or your computers are switched off.

It saves negligible electricity since they use very little current.

It will use negligible bandwidth too, if your computer is switched off.

Will it prolong the life of the router? Possibly. But who cares, the ISP provide them free and will upgrade it eventually or you'll switch ISP.

Switching the router off every night has one disadvantage. It may cause your IP address to change every day (if you have a dynamic one) and this can cause problems for some users who are hosting services, using CCTV cameras, doing gaming etc. That's why some like to keep the router on to retain the same IP address. For others, having a new IP address each day may be a security benefit.

kwikbreaks

WTFH wrote: »

Well, I'm not sure about your routers, but the max power output of the power supply of my BT home hub is 150mA at 6v.last time I did physics, P=VxI.
Max power is therefore 0.9w

Somebody else's is 12v 1000ma..

http://community.bt.com/t5/Other-BB-Queries/Home-Hub-3-Power-Supply/td-p/246655

Hi Geoff, just checked my HH3 plug and it's as follows:

BT switching power supply
Model No S018SB1200100
P/N: 253371437
Input 230v 50Hz 300mA
Output 12.0v 1000mA
For use with BT Home Hub 3.0 Type A

On the HHub 3 itself
Rated Input 12V 1A

I've had a number of routers and all had PSUs of similar rating. The VM cable one I have currently is 12v 1500ma. It is likely that the routers actually use a little less than the maximum PSU output but I've cetainly never ever seen a wireless router with a 150ma supply - I suspect that you have misread it.