The fire would heat the room.
This is not the whole truth!.
1st
we needed to know what is meant by "fire".
( What do You mean with temperature of that fire?
Any flame or solid burning substance has very different
temperatures in different places)
2nd
what substace is burning there?
Example:
lets assume a hydrogen/oxygen flame.
this flame has about 2300 °C in the hottest parts.
If we heat the room to that temperature, we will see,
that the "flame" does not heat the room to a higher
temperature, the flame will vanish!
2300 °C is the equilibrium temperature of a hydrogen flame,
at that temperature the forward reaction (burning) is as fast
as the back reaction (decomposition of water).
Such equilibrium temperatures exist for all "fires",
so the general effect of preheating the room is that
the "fire" does not heat any more.
Georg