Oven shelf temperature

[WaterPixie]

Each shelf in an oven is different in temperature with the lower shelf having lowest temperature.

If some food item says to cook on middle shelf at 170c, why not just adjust the temperature till the top shelf is 170c?
Surely that would save money on gas/electric bill as you would need to use a lower temperature for the top shelf, as opposed to the middle shelf.

 

[Barriehie]

Each shelf in an oven is different in temperature with the lower shelf having lowest temperature.

If some food item says to cook on middle shelf at 170c, why not just adjust the temperature till the top shelf is 170c?
Surely that would save money on gas/electric bill as you would need to use a lower temperature for the top shelf, as opposed to the middle shelf.

It also has to do with the rate of heat absorption. The closer you get to a side, top, or bottom, the slower the convection in the oven is to move the heated air over and around the item you're trying to cook.

The top shelf at 370 is going to brown faster but cook slower than the middle shelf at the same temperature.