The price of standby

When you think of saving energy, one of the first pieces of advice is to switch off equipment when you don't use it. It is a free and easy action to save money (it is even tip 6 in our "8 energy saving tips that cost nothing"). But how much energy does standby actually use? We always hear of new technology with ever lower standby power. So does switching things off instead of standby actually save energy and money?

standby.jpgstandby - the not-so-secret energy vampire

To get to the bottom of the problem I took out my plug-in energy monitor and collected the data from my own home entertainment equipment. The results, even for me, were surprising.

The equipment in my home is probably similar to many other homes. A few of the items are particularly energy saving (such as my TV which has various energy saving modes). But otherwise they are standard run of the mill devices. As I am an energy geek I have a plug-in energy monitor (like the Energenie Power Meter), which you place between the plug of the appliance and the wall socket. It can measure the voltage, amps, power and a few other things. For this study it was the power I was interested in.

The power used by the item in Watts multiplied by the time it is used will give us the energy, which is what the electricity supplier charges for. For example if a 20 Watt (W) light bulb was switched on for 1 hour, it would use 20 Watt hours (Wh) of energy, if it was on for 10 hours it would use 200 Wh of energy. Our electricity bills are charged on units of 1000 Wh or 1 kilowatt hour (kWh).

energy-monitor.jpg
a plug-in energy monitor - measuring the TV power in Watts

For each item the idle power use and the standby power use were recorded. Idle power was when the item was switched on but not being actively used, such as a DVD player switched on but not playing a DVD or a Hi-Fi in CD mode but not playing a CD. In the case of the TV, the idle was not used in the calculations, as most people will switch the TV to standby. The standby power was recorded when the "off" button on the remote control was pressed. It was assumed that all the items would be in use for around 5 hours each day, so idle or on standby for 19 hours a day. The costs were calculated at an average unit price of 13p per kWh.

So onto the data:

Device Idle power
(W)
Hours per day Daily idle energy (Wh) Annual idle energy (Wh) Cost idle
(£)
DVD Home Cinema 16 19 304 110960 14.42
Cable box 15 19 285 104025 13.52
Games console 17 19 323 117895 15.33
HTPC (media centre) 30 19 570 208050 27.05
Hi-Fi 28 19 532 194180 25.24
totals 106 114 2014 735,110 £95.56 

 

Device Standby
power (W)
Hours per day Daily standby energy (Wh) Annual standby energy (Wh) Cost standby (£)
DVD Home Cinema 0 19 0 0 0.00
Cable box 14 19 266 97090 12.62
TV 0.5 19 9.5 3467.5 0.45
Games console 2 19 38 13870 1.80
HTPC (media centre) 2 19 38 13870 1.80
Hi-Fi 18 19 342 124830 16.23
totals 36.5 114 693.5 253,127.5 £32.91

 

There were a few surprises collecting the data. The DVD home cinema system appeared to use no power at all in standby, which was definitely a bonus. The TV also had a good standby mode of only 0.5 W compared to full power use of around 100 W. The big surprise was the cable box, which had a standby power use of only 1 W less than idle. My old Hi-Fi was another surprise, the small clock displayed on standby used more energy than the idle power of the DVD player, cable box or games console. One extra thing to note, when the HTPC (media centre) was switched off at the unit, the power pack itself still consumed 0.6 W.

So looking at the table above it is clear than leaving all my equipment in idle mode would cost me £95.56 a year. Even if switched to standby it would cost £32.91 a year. According to the DECC domestic energy bill data the average UK household spends £479 a year on their electricity bill. Therefore switching off your home entertainment equipment when it is not in use could save between 7% to 20% off your annual bill.

So why don't we switch off?  Often the sockets are hidden close to the floor behind the TV in a hard to reach place which makes it difficult to switch off when not in use. So what can be done to make switching off easier?  Well I use a simple and cheap solution, all my equipment is plugged into an extension lead that is plugged into a single wall socket next to the TV. At night I simply switch off that single plug and can sleep safe in the knowledge that all my electrical items are switched off. But if you after a more hi-tech solution there are various energy saving extension leads (such as the Belkin Energy Saving Smart AV Power Strip) that will do a similar job. Most have a special socket that will disconnect all the other devices when it detects the master device switching to standby. So you could plug the TV into the master socket and when you switch it off it will automatically cut the power to the other items. At this point I should probably say that most modern Personal Video Recorder (PVR) equipment, such as a Sky+ box, can take a long time to boot up after being switched off. So it would be best to make your own calculations and see if the saving is worth the extra boot up time.

The data for my own entertainment equipment shows that "saying no to standby" will certainly save me money and energy over the year. Why not try the same calculations yourself and see what you could save?