How Many Watts? Power Consumption Explained
Curious about the cost of powering your PVR, set-top box, Home Hub and other household equipment?
We covered watts and power consumption in Show 30. We'd encourage you to take a listen to the MP3 of the show.
As promised in the show, here's a handy table of costs, plus some tips on how to bring down your electricity bills.
Listen to our audio feature covering Watts, Power Consumption and Energy: |
Cost of running appliances and gadgets
Interested in finding out how much power your home technology and appliances are costing you a year? We've used a standard power meter to identify the cost of running your gadgets and equipment.
Household appliances
| Product | Notes | Watts | Cost per hour | Daily usage (hours) | Estimated cost a year |
| 60 watt lightbulb | Standard bulb | 60 | £0.007 | 5 | £11.89 |
| Energy-saving bulb (Philips) | Equivalent to a standard 60 w bulb | 11 | £0.001 | 5 | £2.18 |
| Kettle | Average kettle 1800 watts | 1800 | £0.195 | 0.25 | £17.83 |
| Washing Machine | Average cycle (2000w heat, 500w spin, 250 wash) | 700 | £0.076 | 2 | £55.48 |
| Fridge | Average fridge consumes 35 watts | 35 | £0.004 | 24 | £33.29 |
Computing
This page was actually put together as a result of a stack of requests to find out how much power the BT Home Hub uses, and how much it costs to run this router each year. Here are some numbers for the Home Hub and other computing gadgets.
| Product | Notes | Watts | Cost per hour | Daily usage (hours) | Estimated cost a year |
| LCD Monitor | 17" Sony | 75 | £0.008 | 8 | £23.78 |
| Desktop PC | Average 60w idle, 120 loaded | 90 | £0.010 | 8 | £28.53 |
| Router - BT Home Hub v1.0 / 1.5 | wi-fi enabled | 8 | £0.001 | 24 | £7.61 |
| Router - BT Home Hub v2.0 | 10 watts (7 watts powersave) | 10 | £0.001 | 24 | £9.51 |
| Homeplug Powerline adapter | D-link Ethernet Devolo Hs85 | 3 | £0.000 | 24 | £2.85 |
| Printer (idle) | Estimated 3w | 3 | £0.000 | 24 | £2.85 |
TV and Video
| Product | Notes | Watts | Cost per hour | Daily usage (hours) | Estimated cost a year |
| TV - LCD (Sony Bravia KDL32S3000) | When on | 115 | £0.012 | 4 | £18.23 |
| On standby | 0.6 | £0.000 | 20 | £0.48 | |
| PVR (Humax PVR9200TB) | When on | 20 | £0.002 | 4 | £3.17 |
| On standby | 6 | £0.001 | 20 | £4.76 | |
| Sky+ (Thomson 160) | When on | 24 | £0.003 | 4 | £3.80 |
| On standby | 12.2 | £0.001 | 20 | £9.67 | |
| BT Vision Box | When on | 22 | £0.002 | 4 | £3.49 |
| On standby | 21 | £0.002 | 20 | £16.64 | |
| Top Up TV Anytime (Thomson DTI-6300) | When on | 18.2 | £0.002 | 4 | £2.88 |
| On standby | 17.3 | £0.002 | 20 | £13.71 | |
| DVD Recorder (SONY RDRGX120) | When on | 17 | £0.002 | 4 | £2.69 |
| On standby | 3.5 | £0.000 | 20 | £2.77 |
Other Equipment
| Product | Notes | Watts | Cost per hour | Daily usage (hours) | Estimated cost a year |
| Nokia mobile charger | Nokia 6033, screen on | 4 | £0.000 | 24 | £3.80 |
| iPhone 3G charger | Charging with screen off | 2 | £0.000 | 24 | £1.90 |
How these results are calculated:
We've calculated these prices based on the rates of a standard UK Electricity provider. Here's what we've used:
Provider: Scottish Power (Tariff: Fixed Price, London)
Rate: 10.857 pence per kilowatt-hour
Rate last checked: 1st August 2011
How to calculate the cost of equipment usage:
It's easiest to take the example of the good old 60 watt electric lightbulb.
How many watts? 60. The watt is a measurement of power - so you can say 60 watts of power are required to make this lightbulb light up.
The measurement of watts is only meaningful when calculating cost, if you use watt-hours (how much to light the bulb for an hour).
Your electricity provider will bill you by the kilowatt-hour (kWh), and that's what your electricity meter records.
A 60 watt lightbulb left switched on for one hour is equal to 0.06 kWh (divide 60 watts by 1000 to get the kW) - so you multiply 0.06 kWh by your provider's kWh price, to get the cost.
E.g: 60 watt bulb for one hour = 0.06 kWh , multiply by a rate of £0.10 per kWh... is £0.006
Listen to our audio feature covering Watts, Power Consumption and Energy:
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Recommended Products:
Want to keep an eye on your kilowatt-hours? We recommend the following meters:
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Efergy Energy Saving Meter 
Your questions answered
Q. Does a shaver socket use power when there's nothing plugged in?
If you have a shaver socket that uses an isolation transformer (most do), and it doesn't have an on-off switch (most don't), then yes, the shaver socket will use a minimal amount of power (we estimate 1 or 2 watts) when there's nothing plugged in.
Q. How much does it cost to recharge batteries?
After a question from a listener in Show 60 - We finally solved the "are rechargeable batteries cheaper?" question. See our Rechargeable vs Normal Batteries maths
Got a comment or question? Please post in our Technical Discussion forum
Got a question about power consumption that we can answer in our next podcast?
Call 020 8133 4567 or send us a message
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