I don't know what kind of incubation setup you have but be really careful with this. There are people on here that had problems with temps and humidity because they were doing this . I know with my setup if the temp outside my incubator is around 75 it can take the thing about two hours to come back up to temp. I am on ambient temps in my snake room now so it really never gets below 85 in there this time a year and the humidity is not a problem where I live so it is no big deal for me to open my incubator. The temptation is high, however every time you screw with the eggs you increase the chance of a problem.
The incubator that I have has a clear viewing window so I never have to open the door to let out any heat.