If the incubator is properly insulated, a small change in the room temp shouldn't cause a spike inside the incubator. I am incubating at about 87.5 this year. Also keep in mind, that a good proportional tstat is key. The Helix DBS1000 is internally calibrated to .25 of a degree but the display reads in full degrees. The Herpstat ND has an internal resolution of .11 degrees and is accurate to .9. It displays in tenths of a degree. Another thing to realize is that most thermometers including the Accurite and the PEs have a tolerance of +-3 degrees. That is a big number and all the more reason to choose a quality tstat and trust it to get the job done.