OK, I did a quick sanity check with a hypothetical cylinder, using natural convection. Ambient at 20 C. (Just the trend is being examined.)

The cylinder temperature will increase while the heat output stays constant at that same input level, when the emissivity is strongly decreased.

The power required to reach a given temperature will decrease when the emissivity is strongly decreased, however the output power also decreases commensurately with the input power decrease, so that the total heat is conserved.

100.875 W in --------> E=0.85 -----------> 100.875 W out

................................... T=50.0 C .......................................

.

.

100.734 W in --------> E=0.08 ------------> 100.734 W out

................................... T=70.5 C .......................................

.

.

52.602 W in -----------> E=0.08 -------------> 52.602 W out

.................................... T=50 C ..........................................

.

.

190.728 W in ---------> E=0.85 ------------> 190.728 W out

.................................... T=70.5C ........................................