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[HPsauce]

was it you who originally suggested the 1W = £1 a year, formula?

I don't think so, but even now it's a reasonable rule of thumb.

Mind you, it's hugely different for interior or exterior lighting or electrical equipment. Exterior any heat produced is of minimal use, internally it potentially saves on other sources of heating.
(Even an inefficient now-banned vacuum cleaner helps warm the house!)

I spend a fair bit of my day in my "home office" and the equipment in there usually keeps it "comfortable" without needing to heat the rest of the house.  8)

[sevenlayermuddle]

Mind you, it's hugely different for interior or exterior lighting or electrical equipment. Exterior any heat produced is of minimal use, internally it potentially saves on other sources of heating.
(Even an inefficient now-banned vacuum cleaner helps warm the house!)

Couldn't agree more.

Biggest change I ever achieved was in our Lounge, which is heavily overshadowed and so the wall lights are on most of the time, even in daytime, at least in winter.  I changed the wall lights for LEDs and it made created a very obvious step drop in electricity consumption.   But the increase in winter gas for CH was an equally obvious step change!

Probably was a worthwhile overall saving, but the calculations are nowhere near as clear-cut as most people imagine.

[NewtronStar]

Your sums are out by 4 weeks i.e. 52 weeks in one year whereas you are multiplying 4 (weeks) by 12 which is only 48 weeks. Another 4 weeks would add another 67.2 KWh per year approx £10.50

OK thanks yes you should use 365 days and to get monthly usage divide by 12 and divide by 4 to get weekly usage and so on 

[HPsauce]

Biggest change I ever achieved was in our Lounge, which is heavily overshadowed and so the wall lights are on most of the time, even in daytime, at least in winter.

Ours is not dissimilar, a big room with limited radiators but lots of lighting, though well-insulated.

We have four 100W (each) halogen uplighters on the walls, plus a 200W halogen standard lamp and a 150W halogen lamp over the dining table as well as a 100W central light (used rarely) and various minor spot light sources.

I have no intention of changing any of them as it will get cold, though all four wall lights used to be 2*60W each until we updated them to a more modern design!

[NewtronStar]

Biggest change I ever achieved was in our Lounge, which is heavily overshadowed and so the wall lights are on most of the time, even in daytime, at least in winter.

Ours is not dissimilar, a big room with limited radiators but lots of lighting, though well-insulated.

We have four 100W (each) halogen uplighters on the walls, plus a 200W halogen standard lamp and a 150W halogen lamp over the dining table as well as a 100W central light (used rarely) and various minor spot light sources.

I have no intention of changing any of them as it will get cold, though all four wall lights used to be 2*60W each until we updated them to a more modern design!

My biggest saver was to get rid of the 32 inch widescreen tv cathode ray tube and purchase a 40 inch LED TV the CRT was pumping out 120 watts per hour the LED 40 inch is only pumping out 45 watts.

[sevenlayermuddle]

My biggest saver was to get rid of the 32 inch widescreen tv cathode ray tube and purchase a 40 inch LED TV the CRT was pumping out 120 watts per hour the LED 40 inch is only pumping out 45 watts.

I don't quite understand the concept of 'Watts per hour'? 

HP has already given a good explanation of the various units.  I have also pointed out the differences between power and energy.

You maybe need to take a different view... the CRT was providing 120W of heating power for your comfort, whereas the LED set provides only 45W of heating power.  So your heating now has a deficit of 75W, which will be made up by CH if you have it; that much is unavoidable physics.   

That may be a good thing, or a bad thing economically, it depends on whether your house actually needs the heat  (ie summer or winter), how much you pay for gas vs electricity, and the relative efficiencies between gas/electric by which the energy is converted to heat.   

Gas is usually a lot cheaper per kWh, but a lot of energy from any gas boiler goes straight out of the flu, heating up the outside world, and that lost energy contributes nothing to heating your home.   In contrast, Pretty much ALL of the electrical energy that you get billed for is converted into heat within your home - which is probably where you want it.

[NewtronStar]

I don't quite understand the concept of 'Watts per hour'? 

Well there you go 

If you where the person who forks out the bill for electricity being used in the household you would definitely know what is a kilowatt hour and a Watt hour.

here is a tutorial http://www.energylens.com/articles/kw-and-kwh

enjoy

[Chrysalis]

question for others.

if you measured all device usage to be e.g. avg of 5 watts per hour across hour for day.
but the actual meter increased by say 12 per day.

what would you do?

[sevenlayermuddle]

question for others.

if you measured all device usage to be e.g. avg of 5 watts per hour across hour for day.
but the actual meter increased by say 12 per day.

what would you do?

You may have to clarify the question as 'Watts per hour' has no meaning (* see edit) that I can recollect in the physics of power and energy.  I have tried to work out what it might equate to, but my head just starts to spin.

I assume you mean the device's average consumption, calculated over a 24 hour period, is 5W.   But what does the '12' refer to?

* edit..  of course, it is simply a rate of change of power.   A device rated at 5W per hour would be consuming 5W after one hour, equating to an approximate annual cost of £5 per year if it then stopped changing.   But if it carried on changing at 5W per hour then after a year it would be circa 24 x 365 x 5 = 43,800W.   If it then stabilised, the second year's usage would be circa £45,000.  Or a lot more obviously, if the 5W per hour increase continued.   

That is why I think the term is being used erroneously in this thread. 

Apologies if this all appears pedantic, but it is a worthwhile debate and worth getting the terminology right.   

[roseway]

Let's just reiterate:

Watts and kilowatts (W and kW) refer to the rate of flow of electricity.
Kilowatt hours (kWh) refers to the quantity of electricity.
Kilowatt hours are kW multiplied by the number of hours.
Kilowatt hours are what you pay for.

"Watts per hour" has no meaning.

[sevenlayermuddle]

"Watts per hour" has no meaning.

Sorry Eric, my naughty edit to previous post collided with your post.   But I basically agree!

[Chrysalis]

question for others.

if you measured all device usage to be e.g. avg of 5 watts per hour across hour for day.
but the actual meter increased by say 12 per day.

what would you do?

You may have to clarify the question as 'Watts per hour' has no meaning (* see edit) that I can recollect in the physics of power and energy.  I have tried to work out what it might equate to, but my head just starts to spin.

I assume you mean the device's average consumption, calculated over a 24 hour period, is 5W.   But what does the '12' refer to?

* edit..  of course, it is simply a rate of change of power.   A device rated at 5W per hour would be consuming 5W after one hour, equating to an approximate annual cost of £5 per year if it then stopped changing.   But if it carried on changing at 5W per hour then after a year it would be circa 24 x 365 x 5 = 43,800W.   If it then stabilised, the second year's usage would be circa £45,000.  Or a lot more obviously, if the 5W per hour increase continued.   

That is why I think the term is being used erroneously in this thread. 

Apologies if this all appears pedantic, but it is a worthwhile debate and worth getting the terminology right.   

I meant units so killowatts, sorry.

[Dray]

I thought a unit is a kWh?

[sevenlayermuddle]

I meant units so killowatts, sorry.

Again this must sound pedantic, 'Watts' are a measure of power, whereas but 'units charged' will refer to energy, not power.  Most suppliers state their units in kWh for billing purposes.

However... a 5W device, over 24 hours, will consume 120 Watt-hours, or 0.12kWh.  With shifting of a decimal point, than can obviously appear as  '12 somethings' on a meter's display.  Could that be the '12' in the question, and explain what you are seeing?

[HPsauce]

Let me correct that for you.... 

"Watts per hour" has no meaning that is relevant or useful for the calculations in this discussion

I'm sure we could find a use for it somewhere, but I'm struggling to think where, though I can understand what the words mean. It's the hourly rate of change of Watts (in what?)....