What are best and worst energy efficient appliances

Michael_Blackledge

Hi,

Just wondering what are the best and worst efficient and most power consuming appliances. I know its always good to switch off the telly properly when not using it (rather than leave it on standby) but what about computers, alarm clocks, radios, etc. If it doesn't have one of those energy efficient stickers like you get on fridges and dishwashers how do you you know generally what are the worst and best?

I've tried surfing for ages, and no site seems to have a straightforward answer. Any links and ideas anyone please?

Michael B.

blacksta

Electric heaters, deep fryer, electric kettles and irons . All consumer a lot of energy but we can do without them

Cardew

In general heating devices consume the most power.

There has been a couple of threads on standby consumption for TVs etc. Modern TVs left on standby 24 hours a day use very little - their cost can be measured in pence per year; dito most electronic devices like alarm clocks, timers etc.

There are conservation web sites that still quote standby consumptions for TV's of a bygone age.

The consumption of computers is much more complicated. With all drives running they can consume 200-300 Watts but Microsoft estimate the average for a machine that is in use is around 60 Watts. TFT monitors use much less than CRTs. Depending on your power settings the consumption can drop dramatically on standby; but not to the levels of TVs.

Put it this way if someone is really worried about that level of power consumption, they would be far better off accurately measuring how much water they put in their kettle when brewing a cuppa. You will 'waste' far more boiling a cupful of water that you don't use.

Xbigman

blacksta wrote:

Electric heaters, deep fryer, electric kettles and irons . All consumer a lot of energy but we can do without them

But some of those items are efficient.

An electric heater on economy 7 heating one room is cheaper than gas.
A kettle is 100% efficient at heating water.
A deep fat fryer is more efficient for chips than the oven for doing oven chips but deep fat fried food is evil and should be banned.

One mans efficient is another mans wastage.

Likewise, most appliances today are low usage in standby BUT it is always a good habit to get into and be a turner - off'er of everything.
Regards




X

Cardew

Xbigman wrote:

But some of those items are efficient.

An electric heater on economy 7 heating one room is cheaper than gas.

I agree that an electric heater on E7 can(not always - it depends on tariff) produce heat cheaper than gas. However it depends how you define efficiency.

Assuming that you are referring to electric storage heaters(as few want to heat a room in the early hours of the morning) I would question that they are more efficient, or in this context economical.

If you want to use every scrap of heat produced by a storage heater, they may be more efficient. However if you want to use the room for a short while ‘instant’ gas heating is more economical.

For instance a Ferrari V12 engine producing 450bhp has a higher volumetric efficiency than, say, a Ford Fiesta engine producing 50bhp. So is it more efficient in producing power? Obviously the answer is Yes but

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Xbigman

Cardew wrote:

I agree that an electric heater on E7 can(not always - it depends on tariff) produce heat cheaper than gas. However it depends how you define efficiency.

Assuming that you are referring to electric storage heaters(as few want to heat a room in the early hours of the morning) I would question that they are more efficient, or in this context economical.

If you want to use every scrap of heat produced by a storage heater, they may be more efficient. However if you want to use the room for a short while ‘instant’ gas heating is more economical.

For instance a Ferrari V12 engine producing 450bhp has a higher volumetric efficiency than, say, a Ford Fiesta engine producing 50bhp. So is it more efficient in producing power? Obviously the answer is Yes but

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I agree. Electric storage heaters heat the room they are in all day (even if you close the vents they are still releasing heat slowly) so if they heat for 24 hours and you are only in for 6, they are no more than 25% efficient. If they were 20% of the cost of gas that would be fine, but they are more. It all comes down to personal circumstances. If you were heating a room 12 hours a day by gas then E7 would probably be cheaper. But if you heated more rooms then gas becomes more efficient. Its a bit of a nightmare.
Regards




X

meadowcat

I recently checked my meter before and after running my dishwasher. I was using a 65 degre cycle. I was a bit taken aback that I had used 4 units. NIE charge .0995p. plus VAT for a unit, so if I used my dishwasher every day for a quarter that would be over £36 on my bill!!

I have started using a shorter cycle at 50 degrees

Cardew

meadowcat wrote:

I recently checked my meter before and after running my dishwasher. I was using a 65 degre cycle. I was a bit taken aback that I had used 4 units. NIE charge .0995p. plus VAT for a unit, so if I used my dishwasher every day for a quarter that would be over £36 on my bill!!

I have started using a shorter cycle at 50 degrees

That is heavy!

My dishwasher(a 3 year old Bosch) only has a 65C temperature setting but economy/normal/super programmes(+ pre-rinse) The handbook gives the maximum power consumption for any programme with cold water input as 1.5kWh which at the electricity rates I pay(7.16p a unit) is approx 11pence. Used every day that would be £10 a quarter.

I wonder if your consumption or mine is closer to the average?

As a matter of interest the water use is 17/20/26 liters per cycle.

Mr_Proctalgia

I think that on a technical view of the OP's question then different view has to be taken.
Any gas or oil fired appliance that is flued to the outside world will show a lower efficiency than say a catalytic gas fire, therefore in a way a gas cooker is 100% efficient as it will eventually give up all its heat to the structure of the building it is in whereas the best central heating boiler may achieve 90% efficiency under optimum conditions.

I think that as far as electrical appliances are concerned anything that is producing heat as a bye product of what it is supposed to be doing is less than optimally efficient, consider for instance, a vacuum cleaner - Have you ever felt how hot the exaust air is, that shows a lack of efficiency as you want suction not heat from the motor, however the heat is being given up to the house structure and thus not totally lost. There is a further complication when you start to consider the Power Factor of electric motors, my washing machine is showing a PF of only 30% when on spin and I cannot see how a variable speed motor can be optimised further without altering the capacitor value as speed increases. However on balance I believe that the most inefficient item in any home is the humble incandesent lamp as more than 90% of the electricity consumed is wasted as heat.

A further point of interest is modern heat pump air conditioning systems, these are designed to run "backwards" and produce heat as well as doing the conventional cooling, the odd thing is that they can and do produce more heat than their consumption of electricity would indicate, it is not unusual with the latest Toshiba systems to get almost 3kw of heat for 1kw of electricity - this is due to the latent heat in the refridgerant!

Xbigman

But a lot of that only applies if you want the heat. Take the vacuum cleaner. In summer the heat given off is not wanted, in really hot weather you would have to factor in the cost of a fan or air conditioning electricity costs. Same with ovens, fridges etc. At which point its all becoming a bit silly.
Regards





X

Cardew

Mr_Proctalgia wrote:

I think that on a technical view of the OP's question then different view has to be taken.
Any gas or oil fired appliance that is flued to the outside world will show a lower efficiency than say a catalytic gas fire, therefore in a way a gas cooker is 100% efficient as it will eventually give up all its heat to the structure of the building it is in whereas the best central heating boiler may achieve 90% efficiency under optimum conditions.

I think that as far as electrical appliances are concerned anything that is producing heat as a bye product of what it is supposed to be doing is less than optimally efficient, consider for instance, a vacuum cleaner - Have you ever felt how hot the exaust air is, that shows a lack of efficiency as you want suction not heat from the motor, however the heat is being given up to the house structure and thus not totally lost. There is a further complication when you start to consider the Power Factor of electric motors, my washing machine is showing a PF of only 30% when on spin and I cannot see how a variable speed motor can be optimised further without altering the capacitor value as speed increases. However on balance I believe that the most inefficient item in any home is the humble incandesent lamp as more than 90% of the electricity consumed is wasted as heat.

A further point of interest is modern heat pump air conditioning systems, these are designed to run "backwards" and produce heat as well as doing the conventional cooling, the odd thing is that they can and do produce more heat than their consumption of electricity would indicate, it is not unusual with the latest Toshiba systems to get almost 3kw of heat for 1kw of electricity - this is due to the latent heat in the refridgerant!

My goodness we are getting technical!

Many will not understand the term ‘Power Factor’. Simply explained it is a measure of how efficiently supplied electrical power is consumed.

However my understanding is that it has no cost implications in domestic situations as the consumer pays for the kW supplied(not kVA).

In factories etc if your Power Factor is measured and if it drops below a certain level(a bad thing!!) you are charged a premium on the power you consume.

Interesting comments about the efficiency of a gas cooker and the “humble incandescent lamp” and I suggest that there is something of a contradiction in your argument! If a gas cooker giving heat up to the structure of the building can be viewed as 100% efficient, then can not the same argument be applied to an incandescent lamp? The point being that in many cases the heat produced as a bye product is not required; indeed you may need a Toshiba Aircon system to get rid of it!!