how much energy does a 3Kw oven use?

[Sideways]

With the myenergi app for solar diverter, car charger and the like I can see house demand in kW in almost real time.
We have a NEFF oven (bake off type thing, my wife and daughters are great cooks and make good bread and cakes for us)
It's German, designed to be wired into a 16Amp circuit, and pulls 3.5 to 4kW while heating up.
It gets to temperature pretty quickly - just 10 to 15 minutes depending whether you are going for 200C or less.
After that, it switches off except for the circulating fan - a couple hundred Watts if that - and every few minutes switches back on a 2 to 2.5kW for a minute or two to maintain temp.
One a longer cook, the average is far less than 3.5kW
The more often you open the door and put stuff in and out the more it takes.

 

[Spectric]

The ovens and wiring in Germany is different, each room is its own 16A radial split to supply lights and sockets. Each appliance is on its own 16A radial as well as they don't use ring mains and fused plugs.

The Uk is as far as I know the only country to use the outdated ring main, not only does it date back to the early post war years where copper was in short supply but when the domestic household demand was a lot less. For the last twenty plus years I only fitted radials, I really do not like the old ring main.

 

[Lorenzl]

Each appliance is on its own 16A radial as well as they don't use ring mains and fused plugs.

From memory when I was in France every socket is taken back to the consumer unit? I remember seeing a house with about 0.5m of wall covered in cables going into the consumer unit.

For the last twenty plus years I only fitted radials

From what I understand radials are getting more common. I rewired a garage a few years ago and the electrician told me to make it a radial. The electrician I am engaging for the new house restoration said he will use radials except for the kitchen.

I would think in new houses they will still be radials as the cheap skate electricians the builders use wont want to lay out any more than they have to. They like to save as much money as they can as I have learnt from experience. Very shallow back box's and switches/ceiling roses you can barely get to the wires behind. It makes me angry as a couple of inches of extra wire is pence.

 

[Spectric]

electrician I am engaging for the new house restoration said he will use radials except for the kitchen.

Thats a strange decision, I cannot see why any electrician would use a ring in a kitchen. As I said I have not used rings for many years but at the same time I also do not use the split consumer units with two RCD's because it is much better to use RCBO's so as each circuit is protected individually for both fault current and residual current without impacting any other circuits when tripped, with RCD's you lose every circuit protected by that RCD. I put freezers / fridges on their own circuit, many ovens and hobs need their own circuit anyway because of the current demand and general sockets can be on a 32 amp 4.0 mm radial.

Yes the modern house, I have seen them where you cannot put two back boxes for light switches back to back because the wall is just to narrow and they don't deliberately scrimp on the wiring, it is just a case of you cannot have two much otherwise it will not fit in the back box.

 

[Scruples]

I know this seems obvious, but Im thinking once an oven reaches its set temperature, it then only needs enough energy to maintain that temperature

I dont know how an oven works, but I guess it has a thermostat and that calls for heat as required.

are there any electrical engineers that can shed some light

(my wife is asking about what meals would cost less in energy costs to cook -so Im interested to know before I have to spend all winter eating salads )

You're right. Once the oven has reached its set temperature it cuts out until the temperature drops enough to trigger the stat again. Several things determine the energy use: the size of the oven, the element size, the effectiveness of the oven's insulation and, as mentioned somewhere else, the amount of times the oven is accessed.

The only real way to measure the oven's energy use is to shut off everything else electrical. Note the cost on the Smart Meter, if you have one, at the start and at the end of the cooking period. Use the difference in the two figures to work out the actual cost of the oven's energy usage for the test period. Find your unit price from your supplier's info and work out the energy used in kW/hrs.

Oven elements, on stand-alone ovens, tend to be rated at 1.2kW to 1.8kW for fan ovens, and around 2.5kW for conventional ovens and so will happily run from a 13A socket. As would a similar hob. This can make the usual 30A cooker supply obsolete in most cases. It's useful to have DP switches above the worktop to isolate the oven and hob quickly, if necessary.

Using a clamp-meter isn't really an option as it only measures the current for the duration of the thermostat's 'on' cycle. The smart meter takes everything into account. HTH

 

[Jameshow]

Obvs the higher temp the shorter the cut out time. So cooking at 100° will take alot less electricity than at 220°

Winds me up went my family cook a pizza at 200° and burn it slightly when 150 would result in a much more eatable pizza and less electricity used!!!

 

[hawkeyefxr]

I have noticed some modern ovens can run off a 13A socket. If yours does you could get a plug in energy meter to put inline.

If yours is wired into a isolator and you can access one wire ( live ) to your oven somewhere you could use a clamp meter.

Your right about the 13A plug device, we have recently had a hob fitted and it it way more efficient that a gas one. An inch of deep water in a medium saucepan starts to boil in 30 seconds.

 

[Chris Hawkins]

I can answer the OP I bought a power meter and have been trying to track down my high power usage (circa 6000KWh pa) in the house. I have been unpleasantly shocked ) ) by many appliances - notably my fridge/freezer (620 Kwh per year) which is quite old. Anyway, the NEFF oven (a relatively expensive one and about 12 years old) pleasantly surprised me. At 180 Fan, it used a tad under 1KWh per hour.

 

[Jameshow]

I can answer the OP I bought a power meter and have been trying to track down my high power usage (circa 6000KWh pa) in the house. I have been unpleasantly shocked ) ) by many appliances - notably my fridge/freezer (620 Kwh per year) which is quite old. Anyway, the NEFF oven (a relatively expensive one and about 12 years old) pleasantly surprised me. At 180 Fan, it used a tad under 1KWh per hour.

So probably 1/3 cycle of 3kw???

 

[akirk]

of course the other factor needing to be considered is efficiency...
Recent article online in the telegraph mentions:
- gas hobs are 40% efficient
- electric (presumably ceramic as well) are 74% efficient
- induction is 90% efficient
I suspect that ovens also have a similar range of efficiency
so, not just a matter of how much power, but if high efficiency you will use it for less time anyway...

 

[Phil Pascoe]

... it is just a case of you cannot have two much otherwise it will not fit in the back box.

There's usually no reason a loop of wire shouldn't be left in the wall outside the box to be pulled through if needed, though. I always did and often was glad I had done.

 

[mossberg]

I used to design ovens for the paint finishing industry. We had a set load of input that calculated our burner size. I can't remember the calculations but the heat losses were based on loss of energy through the walls, the product being heated and, in the case of industrial ovens, a bleed of 10% of the recirculation rate which was by far the biggest energy loss.

The 3kw element is just the size of the energy input to perform the task.

So things that will take the energy are the heat loss through the oven walls. The higher your internal temperature the more energy you will loose through the walls.

You then have to heat the air, the actual material forming the oven structure, other materials such as shelves and finally the "product" (what you are cooking). Remember that the energy input has to raise the temperature of the mass of the product, so if you put 1/2kg of dough in a 2kg cast iron vessel then you have to heat that too. If you put the dough in a pressed steel tray then you need less energy to heat the vessel.

Filling your oven with more product (mass, not number of items) will take more energy to heat that mass. It may also take longer to heat which means more heat loss through the walls.

Also remember that the more you open the oven door to stick forks in things the more energy will be lost by allowing the heated air to escape to be replaced by ambient air which will need heating.

We used to have some pretty power hungry kit at times. Electrical heating elements in the 160kw range and gas powered units at much more (450kw)- but then some of our ovens may be 10x6x3m etc with temperatures up to 220 degrees and have open ends to allow products to pass through on a conveyor.

 

[philogos]

Won't this depend on the heat loss from the oven? The oven will switch on to replace heat lost through its walls or e.g. when the door is opened. The rate of heat loss should depend on the amount of insulation and the thermal gradient between the inside of the oven and the rooms, so will also vary with the temperature setting of the oven. Which suggests saving money by cooking in bulk, defrosting first in the fridge and using air fryers or combi microwaves for smaller items.

 

[simoncmason]

From memory when I was in France every socket is taken back to the consumer unit? I remember seeing a house with about 0.5m of wall covered in cables going into the consumer unit.


From what I understand radials are getting more common. I rewired a garage a few years ago and the electrician told me to make it a radial. The electrician I am engaging for the new house restoration said he will use radials except for the kitchen.

I would think in new houses they will still be radials as the cheap skate electricians the builders use wont want to lay out any more than they have to. They like to save as much money as they can as I have learnt from experience. Very shallow back box's and switches/ceiling roses you can barely get to the wires behind. It makes me angry as a couple of inches of extra wire is pence.

In France each appliance is on it's own line back to the consumer unit.

But you can have up to 12 single sockets on 2.5mm cable or 6 on 1.5mm. Everything is a radial.

The consumer units end up being huge in a modern house - ours is two boxes with 7 rows of MCBs.

Also common to see 3 phase in domestic houses - ours is, which is good for the oven as we have a 3 phase 400V Rangemaster which gets to temperature very fast!

Probably should check the consumption but our overall usage is low so it can't be too bad, but mostly cook (and heat) on our wood-burning stove all winter from our own wood

 

[MikeK]

In France each appliance is on it's own line back to the consumer unit.

But you can have up to 12 single sockets on 2.5mm cable or 6 on 1.5mm. Everything is a radial.

The consumer units end up being huge in a modern house - ours is two boxes with 7 rows of MCBs.

Also common to see 3 phase in domestic houses - ours is, which is good for the oven as we have a 3 phase 400V Rangemaster which gets to temperature very fast!

Probably should check the consumption but our overall usage is low so it can't be too bad, but mostly cook (and heat) on our wood-burning stove all winter from our own wood

This is what a typical 3-phase residential electrical distribution panel in Germany looks like and this is the panel in my detached 3-level house. The second row of 16A breakers has four spares that aren't connected to branch circuits yet.

 

[Richard_C]

Someone above mentioned hobs running off a 13a socket. Yes, perfectly possible "but". I got a new induction hob recently, one ring on the very old ceramic one had died and the parts cost for a new ring seemed high in relation to new hobs so I spent the extra. Having looked at various models I found that the 13amp socket ones use clever controls to manage the current, you can have one heating zone on high and the others ticking over but if you ask for more it reduces current to one or all. The wired in ones also use management but you can use more power simultaneously. Not an issue for many people but I decided to go wired.

Seems excellent, don't much like the beepy touch controls but the only induction one with proper knobs cost a big lot more. My aluminium mokka pot doesn't work of course but everything else did.

I did think I might have to replace the 18 year old Bosch cooker but managed to fix it, light fitting had corroded and was hanging out. When I started to look around I was a bit disappointed that nothing seems to have advanced in the intervening years. Some designs seemed bonkers, an AEG with pop out controls, easy to keep clean, but the temperature marks on the top edge of the button. In an eye level installed double oven you need to stand on a box to see what temperature you are setting it to. I guess someone decided the knobs they used on under counter ovens would be fine.

Good to have all the consumption information, thanks. I had thought I might video record the oven for an hour then play it back fast and see how long the red light was on for but that seems unnecessary now.

 

[simoncmason]

This is what a typical 3-phase residential electrical distribution panel in Germany looks like and this is the panel in my detached 3-level house. The second row of 16A breakers has four spares that aren't connected to branch circuits yet.

View attachment 142715

View attachment 142716

View attachment 142717

Similar to the one in our house, except the meter is a Linky outside on a pole and the supply comes through a main switch - installed and maintained by EDF - so the consumer unit itself just has the four 10mm supply cables coming in the top onto to four distribution points which have 6mm cable links to the RCD at the left of each row of MCBs - each row of MCBs has to have it's own RCD, with yet another separate dedicated ones for Fridge/Freezers on ours, though that is recommended not compulsory.

Also all the MCBs in France have to be double pole which I think is probably a good idea.

The other obvious difference is the Earth bus is at the bottom of the unit, as far away as possible from the P and N input. Surprised to see the Earth right next to the Neutral on your German unit.

 

[Phil Pascoe]

I got a new induction hob recently ... My aluminium mokka pot doesn't work of course but everything else did.

Be careful when you buy stainless pans - some work and some don't.

 

[HamsterJam]

Won't this depend on the heat loss from the oven? The oven will switch on to replace heat lost through its walls or e.g. when the door is opened. The rate of heat loss should depend on the amount of insulation and the thermal gradient between the inside of the oven and the rooms, so will also vary with the temperature setting of the oven. Which suggests saving money by cooking in bulk, defrosting first in the fridge and using air fryers or combi microwaves for smaller items.

You are correct that it depends on temperature gradient and heat loss. Don’t forget also the energy needed to heat up the oven in the first place plus whatever you want to cook. A big lump of cold meat is going to absorb more energy than a meringue.

 

[Richard_C]

Be careful when you buy stainless pans - some work and some don't.

Indeed and a useful warning. Almost all recent ones have a steel bit invisibly sandwiched between the 2 stainless skins so are OK. I was surprised to find my mostly aluminium non stick gravy and custard saucepan has a similar core so works OK. A small magnet is your friend in saucepan shops should anyone be coveting new things take one along in your pocket. If it sticks to the base you are fine for induction. Or you could trust the label or the store assistant, but neither is as reliable as physics and the magnet test.