Lighting technologies develop rapidly and the energy efficiency of LEDs quadrupled between prices have decreased more than 60% in the last decade. The cyanobacterium Arthrospira platensis, commercially known as food supplement Spirulina, has great potential for urban indoor farming due to its high growth rate and low resources needed. This study investigates the combined effects of photoperiod (16–24 h light), light intensity (100–400 μmol photons m−2 s−1), and temperature (27–35℃) on production and energy efficiency in the cultivation of A. platensis in 0.5 L bubble column photobioreactor. This study aimed to develop a cost-efficient LED light regime for attaining maximal production of A. platensis. All experiments under cold white (6500 K) light show higher light energy efficiency than those under warm white (3000 K) light (p < 0.05). The light saturation point was at 261 μmol photons m−2 s−1 for warm white light and was not reached for cold white light. The maximum specific growth rate (µmax) was 2.2 day−1, 30% higher than reported in the literature. This growth rate was obtained at 24:00 light:dark photoperiod 33–35℃ and cold white light; light efficiency was 3 kW g−1 DW. Cultivation under warm white light resulted in 22% lower µmax, and light efficiency was 9 kW g−1 DW. The most economical light intensity was 193 μmol photons m−2 s−1 of cold white light.