electric usage

QrizB

frugalmacdugal said:

daz9643 said:

I decided to check tonight where my standby power is going, my Panasonic combination microwave uses 72W in standby, with the new price cap of 51.8p in October that works out at £326 per year ! 

think you're getting mixed up with Watts and kWh which is 1000 time more.

Watt makes you think that?

72watts x 24 x 365 = 631 kWh/yr.

631 x 0.518 = £326

[Deleted User]

Hi,

ok, so £6ish a week for a gadget to tell the time, mostly.

QrizB

frugalmacdugal said:

Hi,

ok, so £6ish a week for a gadget to tell the time, mostly.

Looks that way. 72 watts of vampire load for a microwave seems quite excessive!

I'm wondering if the microwave has an incandescent light inside, and they did their measurements with the door open (light on)?

pochase

I think @frugalmacdugal got it right with his  0.72w instead of 72w.

The calculation for 72w is of course correct, but a 072w standby sounds much more logical for just an LED. 

What is the model of the microwave.

pochase

I take back the 0.72w.

Here is an almost 15 year old thread about Panasonic microwaves that "seem" to be using 80w in standby.

https://www.avforums.com/threads/panasonic-microwave-using-70w-all-the-time.841118/

My knowledge is not good enough to understand why they conclude that the meters somehow don't work for the microwave. 

A practical test switching everything off except the microwave seems to have proven that it is not 80w.

dunstonh

Coffeekup said:

daveyjp said:

Circa 8% of the power output of the oven just to run an LED display doesn't look right.  7.2w would be closer to reality.

I started turning things off at the wall last September and saved 40kwh a month. I only turned off the washing machine, microwave, TV, sky box, CD player and amplifier, I never had any gizmos but I knew the microwave was a guzzler after a couple of days of readings. Which promoted me to turn the TV, sky box, amp and cd player off at the wall when not in use, I saved more energy but not as much as just turning the microwave off 

Mine is a non branded one from a supermarket, I should give it to a charity shop as I don't use it.

We too found our microwave was using a lot (relatively speaking) when not being used.  About 30w.  It is now off.

chris_n

pochase said:

I take back the 0.72w.

Here is an almost 15 year old thread about Panasonic microwaves that "seem" to be using 80w in standby.

https://www.avforums.com/threads/panasonic-microwave-using-70w-all-the-time.841118/

My knowledge is not good enough to understand why they conclude that the meters somehow don't work for the microwave. 

A practical test switching everything off except the microwave seems to have proven that it is not 80w.

When you have a switch mode power supply it can cause 'noise' which meters that use a current transformer like the Owl meter mentioned in the link cannot  measure accurately. I have an Owl to measure Solar generation, it is fine for that apart from when the inverter is starting up where the same problem occurs. It is hopeless for the house load when it is low, fine when the oven is on with a decent resistive load.

[Deleted User]

pochase said:

My knowledge is not good enough to understand why they conclude that the meters somehow don't work for the microwave. 

If the design is such that there is a large current needed to keep the inbuilt transformer energised at all time, this would be mainly inductive (imaginary power or VAr rather that W) and meters are terrible at spotting and/or translating that.

pochase

OK, we don't know if @daz9643 has just measurer the current power consumption or has measured how much is used over a longer time frame.

The way I understand it is that the current power may be way off, but the usage over a longer time will be correct?

EssexHebridean

I've got a similar Panasonic combi microwave and made the decision to turn it off some time ago as we already have the clock on the oven in the kitchen, and it seemed daft to be paying for both to be on 24/7. I'm quite glad I did decide that now, after all this chat!