Technically, this is not homework but I thought it might be more appropriate here as it is a homework type question but it is for practical use. If the moderator thinks it should go somewhere else, then please move it to wherever you think is more appropriate.

I've not found the answer on the internet. Maybe because I'm not asking my search engine the right question but I'm trying to work out how calculate what power would be required to heat up an enclosed space such as an oven up to a temperature of 50 degrees C.

What equations do I need? Can this be done with linear equations?

-I assume the volume to be heated. (How much does the shape of the space being heated matter?)

-Perhaps the humidity of the air (as a %)

-Air density ρ

-Air pressure P.

But then I start getting lost.

The best I found with my search is that it takes about 0.005 watts to heat up a cubic foot of air by 1 degree F.

However I'm not sure if that power increases linearly - i.e. 0.01 watts to increase it by 2 degrees F. 0.015 watts for 3 degrees etc - as it would translate to just 0.25 watts to heat up 1 cubic foot of air by 50 degrees F (not C).

If that's the case, I could work it all out without too many difficulties but I've seen answers to questions posed on the internet before and prefer things to be backed up by several sources before I believe it... especially if I'm going to make practical use of it.

Many thanks and if my question is a bit open ended, please let me know.