How fast would a body reach thermal equilibrium ?

[Edi]

For example, I place a simple steel cube weighting 1 kg in a room [filled with air] at 20C [room temperature]. - how fast would the cube heat up to 20C (yes, actually equilibrium would be a bit lower than 20C, but lets.. imagine that is is a infinitely large room and .. yes, you get it ) ?
Yes, I know that increasing surface area would increase the rate of energy exchange and moving air [wind] would speed up the process too.. but I don't know the exact figures and formulas.. :(

 

[fluidistic]

For example, I place a simple steel cube weighting 1 kg in a room [filled with air] at 20C [room temperature]. - how fast would the cube heat up to 20C (yes, actually equilibrium would be a bit lower than 20C, but lets.. imagine that is is a infinitely large room and .. yes, you get it ) ?
Yes, I know that increasing surface area would increase the rate of energy exchange and moving air [wind] would speed up the process too.. but I don't know the exact figures and formulas.. :(

I'd use Newton's law of cooling.
$\frac{dQ}{dt}=hA(T_{\text {room}}-T_{\text {cube} })$ where A is the surface area of the cube and h is the heat transfer coefficient (depending on the material of the cube).