LED vs HPS

The LED vs HPS comparison defined indoor cannabis cultivation discussion from approximately 2015-2025 as LED technology matured from inferior to clearly superior. As of 2024-2025, LED has decisively won for new commercial installations, but HPS retains a meaningful market share for specific use cases. LED advantages: (1) Efficiency — modern full-spectrum LED achieves 2.5-3.0 µmol/J (some commercial fixtures reach 3.5 µmol/J) vs HPS at 1.7-1.9 µmol/J, meaning LED produces 30-50% more usable light per watt of electricity. (2) Heat — LEDs convert about 40% of electricity to light and 60% to heat, while HPS converts 30% to light and 70% to heat; this means LED grow rooms run 5-15°F cooler than equivalent HPS rooms, dramatically reducing AC requirements. (3) Spectrum versatility — full-spectrum LED handles both vegetative and flowering with a single fixture, while HPS requires either a separate MH bulb for veg or accepting compromised vegetative spectrum. (4) Operating life — LED fixtures last 50,000+ hours (10+ years of typical use) vs HPS bulbs lasting 10,000-15,000 hours and requiring annual replacement. (5) Dimmability — most modern LED fixtures have integrated dimmers allowing fine-tuning of intensity to match plant lifecycle stage; HPS bulbs run at fixed intensity. (6) Even canopy distribution — LED bar-style and quantum board fixtures provide more uniform PPFD coverage than HPS focal patterns. (7) UV/IR options — premium LEDs include supplemental UV and far-red chips for terpene boost and stretch control, requiring add-on bulbs with HPS. HPS advantages: (1) Lower upfront cost — HPS fixtures cost $150-400 vs $400-1500 for equivalent LED; budget growers can afford HPS more easily. (2) Proven track record — HPS has 40+ years of cannabis cultivation history with established yield benchmarks; some growers prefer the certainty of known performance. (3) Heat as a feature — in cool climates, the high heat output of HPS reduces or eliminates the need for supplemental heat in winter grow rooms. (4) Simple technology — HPS bulbs and ballasts are simple, repairable, and widely understood; LED failures (driver, chip, controller) can be more complex to diagnose and repair. The math has shifted decisively toward LED: a $1000 LED fixture replacing a $300 HPS setup pays back the difference in 1-2 years through reduced electricity costs and elimination of bulb replacements, then continues delivering savings for 8+ more years.