Understanding the efficiency of energy flow in networks is an important challenge for technologies inspired by quantum biological processes. Here we present a simple and intuitive explanation for the intriguing observation that optimally efficient networks are not purely quantum, but are assisted by some interaction with a ‘noisy’ classical environment: By considering the systemʼs dynamics in both the site-basis and the momentum-basis, we show that the effect of classical noise is to sustain a broad momentum distribution, countering the depletion of high mobility terms which occurs as energy exits from the network. We also explore how insights from this picture can unlock dramatic further improvements in performance when a global driving field specifically targets noise at the low mobility.