You want the internal temperatures higher for filaments like ABS, which happens naturally because the recommended bed temperatures are much higher.  With the fans turned on we shoot for internal temps between 35C and 40C for 3D printers that use E3D hot ends because E3D recommends that temp range to avoid clogging.  Keeping the temperatures in that range it puts the least stress on the equipment and follows the manufacturer's guidelines.

This works great for people either interested mostly in air quality or those who are risk-averse and don't want to take a chance of clogging their hot ends or decreasing the useful life of their printers.

More experienced 3D printer owners though, those for whom a clogged nozzle is a known risk, might want to run the temperatures higher for less chance warping of ABS parts or to print nylon.  In those cases, you can turn off the fans or even print one of the vent covers and just not vent at all.  For our internal print farm, we do the later on a couple of machines where the temperature when printing ABS gets as high as 46C.  They've been running like that for years with no filament clogging.  Even with no venting of the power supplies, we've never had a power supply fail either. Obviously, your mileage may vary, as it depends on a lot of variables such as filament quality and the quality of the power supply in that particular printer.

If you're looking for the highest temperature's possible, try turning the bed heater on for an hour before you print.