Why, not having the heating on could turn out to be positively advantages.
The developer will be cold, because the ambient temperature will be that too. So i don't expect any warming up through the tank wall and resulting convection currents in the tank.
Good point about the fixer, though. I'll get that up to 'normal' temperature, and give it a bit longer to work.
If Rodinal is exhausted in 40 - 50 minutes, lower temperatures leading to slower action, why would Rodinal then still be exhausted in 40 - 50 minutes?
I'll try 1:50 for well over an hour, perhaps 2 full hours.