Continental lithosphere plays two roles in the Earth’s heat loss: (1) it locally insulates the mantle beneath it and (2) it sequesters radioactive elements from the convecting mantle. These two roles have potentially opposing contributions to Earth’s heat loss, as the former effect increases the average mantle temperature whereas the latter decreases the internal mantle temperature. Understanding this duality becomes important since the internal mantle temperature influences mantle rheology, melt production, convective vigor and other geological processes that impact the dynamics and chemistry of the Earth’s interior. To determine their net consequence on the Earth’s heat loss, these two competing effects were explored using simulations that incorporated enriched continents within a mixed internal- & bottom-heated convecting mantle. Increasing continental surface area was found to enhance global heat loss for a range of heat production distributions and Rayleigh numbers. The effect of enriched continents was evident as a double peak in the continental surface area values that maximize global heat loss. This double peak effect could reflect trade off between mantle heat production depletion and the increased continental insulation. Finally, the insulating effect of continents was shown to alter the temperature signature associated with bottom- vs. internally-heated convection. In addition, that the presence of continental lithosphere could increase average mantle temperature despite the mantle being depleted suggests that continents can significantly influence mantle potential temperature.