In message , Lawrence
Jenkins writes
On this planet.
If not what are the most important factors that tilt the balance?

You haven't defined your terms sufficiently. But if one were to define
energy in as solar radiation at the top of the atmosphere (I understand
that other astronomical sources are sufficiently small that they can be
neglected) then energy in is obviously not constant. There is an annual
variation due to the eccentricity of the Earth's orbit, and longer
period variations due to variability in the solar output, and changes in
the Earth's orbit.

If you were to define energy in as the energy absorbed at the Earth's
surface, albedo variations become important, as does the axial tilt
(only the proportion of the radiation that hits Antarctica can be
reflected off the Antarctic ice sheets).

Or did you mean to ask whether energy in and energy out are always
equal. That is clearly not the case locally (the hottest and coldest
periods are on average significantly later than the solstices). I
suspect that even if the climate was in equilibrium that would not be
true globally, but there would be annual oscillations, and interannual
variability, in the heat balance. As the climate is not in equilibrium,
some of the incoming energy is going into warming the oceans, so energy
in may be greater than energy out (there's also the matter of ice sheet
balance, but in the absence of knowledge of the magnitude of snowfall
increases in Antarctica I can't be sure whether this is an energy sink
or an energy source.)
--
Stewart Robert Hinsley