Does An Empty Oven

[Tilly2]

warm up quicker than an oven with shelves?

I always take the shelves out when I warm up the oven, prior to cooking.
Is it necessary?

[shoota]

Is that for a solid shelf Graham or a rack with bars?

[Tilly2]

Eccles, I am putting the food in at the same time as I put the shelf in. The food is on the shelf. If the shelf was in the oven, I would still have to open the door to put the food in. What's the difference?

[tonyav]

But shoota, thickness of the metal also makes a difference.

[jomifl]

The more shelves you have in the oven the longer it will take to heat up, but not so as you would notice. Knowing the wattage of the heating elements and the weight of the shelves it would be easy to calculate, but hardly worth the trouble.

[Graham-W]

It's for a shelf weighing 0.25kg which I guessed at. Without going downstairs and weighing one I don't know for sure.
However, if you use 0.0058 kilocal/kg for the calculation you'll be in the right ballpark.

[Tilly2]

So, it really doesn't matter then?

[Graham-W]

The thickness of the metal will play only a minor part to do with conduction. The major factor is the mass of the shelf, and that has only a very minor effect.

[Graham-W]

Tilly2. No. Not really.

[Tilly2]

Ah, well. Thanks anyway, Graham.

[tonyav]

LOL, you had the correct answer at the start of the thread, Yilly.

[sherrardk]

Why don't you time it with and without metal bits and see if it makes a difference?

[Tilly2]

Well, I didn't know that did I, Yont?

[Tilly2]

I will, sherr, I will.

[Graham-W]

Don't forget to take ambient temperature into account. No need to work in degrees Kelvin.

[Tilly2]

Who's Kelvin?

[Graham-W]

Kelvin was a mate of Fahrenheit ;-))

[pusskin]

i have three shelves in my oven and its never crossed my mind to take any out, only to clean them about once every ten yrs! (I wish)

[jno]

the energy will save is already outweighed by the brainpower Graham has had to warm up to answer the question. Something to do with transference of matter, I think.

[Graham-W]

Not so much "transfer of matter" as "it does't matter".