Electrical appliance usage

hebron

Hi, I have been trying to work out how much certain item cost to run, but are getting myself confused.

If an electrical appliance uses 10 watts per hour and according to my bill my electric is between 10p and 22p per kilowatt hour or per unit ( if I understand it correctly).
How much would 10 watts be per hour.

The cost of my electric ranges in price so an average would be about 14p.

I am trying to find out certain items and how much they cost to run like
digibox 5 watt
DVD hard drive 13w
DVD hard drive in standby .9w
I presume these are per hour.


Any help or direction to a website would be appreciated.

Thank you.

CharlieBilly

1/100th of a kwh, so 100 hours use would be 1kw whatever the utility company charge around 10p-20p

dannymccann

The way I would work it out would be:

1kw (1000W) / 10w = 100 hours (so it takes that single appliance 100 hours to use 1kw)

If your average price per kwh is 14p

14p / 100 = £0.0014 / h

moonrakerz

Digibox = 8 days for 14p
DVD Drive = 3 days for 14p
DVD Stdby = 38 days for 14p.

Cardew

CharlieBilly wrote: »

1/10th of a kwh, so 10 hours use would be 1kw whatever the utility company charge around 10p-20p

10 watts is 1/100th of a kWh.

So 100 hours use would be 1 kWh.

CharlieBilly

Yes you are right

Cardew wrote: »

10 watts is 1/100th of a kWh.

So 100 hours use would be 1 kWh.

hebron

Thanks for you help. I'm still having trouble though converting other electrical items into the cost. It's the getting from kwh to watts x how many watts the appliance uses and than working out the daily usage.

I tried to join skill wise for maths this year but I left it too late, I wish I got in now!

Thanks.

Cardew

hebron wrote: »

Thanks for you help. I'm still having trouble though converting other electrical items into the cost. It's the getting from kwh to watts x how many watts the appliance uses and than working out the daily usage.

I tried to join skill wise for maths this year but I left it too late, I wish I got in now!

Thanks.

For most electrical appliances, knowing their rating in kW is no help at all; that is because the appliance has a thermostat,(turns on and off automatically) or has variable power.

For instance your fridge might have, say, a rating of 200 watts. So 2p an hour. However the majority of the time it is using no power at all as the compressor is not running.

Similarly your washing machine might be rated at 3 kWh - so 30p an hour. However on a washing cycle lasting 90 minutes it might only use 0.4kWh costing 4p instead of the 45p you might think. This is because the 3kW is only for the heater and that might only be on for a couple of minutes. The motors to turn the drum use very little power.

You can buy meters cheaply in which you can plug in most appliances and these can be set to display the cost of running most appliances.

amcluesent

I worked out these costs for items in my home, on the basis that 1kWh costs 20p, so adjust to your tariff. All prices are in PENCE!

Per Usage items

Item   KWh   Pence
Kettle (2 cup)   0.08   1.61
Dishwasher   1.3   26.19 

Continuously running items

Item        Wattage    Pence/Hr
Hi-fi (on)    40    0.8
Hi-fi (standby)    15    0.3
PC/LCD (on)    170    3.4
PC (Sleep)    5    0.1
Cable Modem    5    0.1
Wi-Fi Router    6    0.1
Laptop Charger (charging)    45    0.9
Laptop Charger (charged)    25    0.5
Laptop Charger (disconnected)    0    0.0
TV/PVR (standby)    11    0.2
TV/PVR (On)    80    1.6
Fan (cold)    21    0.4
Fan (max)    1970    39.7
Phone Charger (Avg)    1    0.0
Lamp (11W energy saver)    11    0.2
Bedside Lamp    80    1.6
Central Heating Pump    95    1.9
Microwave (Full Power)    1450    29.2
Microwave (Full Power + Grill)    2300    46.3

Note how the fan heater is vastly more expensive to run than small items like phone chargers. One hour of the fan heater will cost the same as the TV & video on stand-by for a week! Rather than run about unplugging these, put on another jumper.

hebron

Thanks you have all been of great help