New TV energy use calculations

Norman_Castle

Checked a friends older TV yesterday, it uses 160w when on. Looking at newer TVs they show this,

https://www.johnlewis.com/samsung-ue43au7100-2021-hdr-4k-ultra-hd-smart-tv-43-inch-with-tvplus-black/p5477654

Energy Consumption in High Dynamic Range per 1000h (kWh)

103 kWh

Energy Consumption in Standard Dynamic Range per 1000h (kWh)

70 kWh

If her TV uses 160w is that 160 kWh per 1000 hours? Is the comparison between the old and new set 160kWh vs 103/70kWh?

molerat

That is the maximum it will use.  The newer models are shown as averaged over a period, they are not like a kettle which is either flat out or off but use a different amount of energy depending on what they are doing as shown by the different mode consumptions.

[Deleted User]

If you have a smart meter IHD it is quite interesting to watch the instant energy kW reading change as the screen changes from bright to dark scenes and vice versa. By the sound of it, your friend does not have a plasma TV. They were known to be energy hungry: a brilliant picture comes at a cost.

Norman_Castle

molerat said:

That is the maximum it will use. 

The 160w? It was measured with a plug in monitor.

Xbigman

What were you measuring?
If the monitor was set to show how much power was being consumed second to second that will be 0.160 kwh per hour. That is sky high by todays standards but not for a really old TV. 


Darren

Norman_Castle

Xbigman said:

What were you measuring?

Energy use in watts.

Coffeekup

To keep things simple, say you friend watches TV 10 hour's a day....

Her old tv will use 1.6 kWh (1,600 watts) a day.

The one you listed will use 1.03 kWh (1,030 watts) a day in HDR mode.
The new one in standard mode will use 0.7 kWh (700 watts) a day.

This doesn't include standby times for the other 14 hours a day.
If they are looking to cut down on her energy usage and are watching TV through a decoder box like free view or sky it'll may be worth looking into these as these can use 0.7 kWh a day in standy that's before you access the hard drive for recording or viewing.

Norman_Castle

The question is about getting a direct comparison given the only available information.

If this, "Energy Consumption in High Dynamic Range per 1000h (kWh) 103 kWh" was plugged into my monitor would it show as using 103w? 103kWh divided by 1000 = 103.

If this, "Energy Consumption in Standard Dynamic Range per 1000h (kWh) 70 kWh" was plugged into my monitor would it show as using 70w? 70kWh divided by 1000 = 70.

If that's correct and my friends tv was being sold today would it state, "Energy Consumption (in Standard Dynamic Range*) per 1000h (kWh) 160 kWh"? 160 times 1000 = 160kWh.

* probably irrelevant to an older tv and to this question.

QrizB

Norman_Castle said:

The question is about getting a direct comparison given the only available information.

If this, "Energy Consumption in High Dynamic Range per 1000h (kWh) 103 kWh" was plugged into my monitor would it show as using 103w?

Probably not. 103W is an average value under standard test conditions. The reading you see in practice will vary depending on a lot of factors, including on exactly what is showing on screen at the time.

It's intended as a guide to allow informed comparisons between appliances.

If that's correct and my friends tv was being sold today would it state, "Energy Consumption (in Standard Dynamic Range*) per 1000h (kWh) 160 kWh"?

For the reasons stated above, almost certainly not.

What make/model is your friend's TV?

Norman_Castle

QrizB said:

Norman_Castle said:

The question is about getting a direct comparison given the only available information.

If this, "Energy Consumption in High Dynamic Range per 1000h (kWh) 103 kWh" was plugged into my monitor would it show as using 103w?

Probably not. 103W is an average value under standard test conditions. The reading you see in practice will vary depending on a lot of factors, including on exactly what is showing on screen at the time.

It's intended as a guide to allow informed comparisons between appliances.

If its an average value wouldn't that take into account small variations such as variable screen brightness when showing different images? I'd expect standard test conditions would be viewing as a consumer would. There will be minor variables but an energy use label cannot accommodate them all.

This suggests my method of comparison is right, https://www.electricalsafetyfirst.org.uk/guidance/energy-labels-explained/

Can I work out the power of my appliance from the information on the energy label?

It depends. Energy labels will give you the amount of electricity used over a period of time or for a given number of uses (cycles) in kilowatt hours (kWh). To work out the power in watts (W) or kW (kilowatts) of your appliance you need to know how the energy efficiency rating was calculated.  Unfortunately, this calculation differs depending on the type of product.  For example, a TV’s rating is measured in kWh per 1000 hours and a washing machine’s rating is based on kWh per 100 cycles at an eco-wash setting.

If you want to know the power rating of an appliance, it’s easier to look at the rating label on the product or the packaging. See an example of a rating label below.

How do I work out the power of my appliance from the kWh?

If the power is constant and you know the time frame, it is easy. You just take the kWh and divide it by the number of hours e.g. 10kWh over 5hours = 2kW. If you need the answer in watts (W) instead of kilowatts you just multiply the answer by 1000. e.g. 2 x 1000 = 2000.

[Deleted User]

I think that the labelling link above is out-of-date following recent changes.

This is the label attached to Samsung’s latest QDLED TV:

Note: G not B.

This is the consumption under test conditions (Rtngs.com)