HPS vs. LED Grow Lights: An Honest Cost-Benefit Analysis
The debate between High Pressure Sodium (HPS) and Light Emitting Diode (LED) grow lights continues to be one of the most discussed topics in indoor growing. This analysis breaks down the true costs and benefits of each technology to help you make an informed decision.
Initial Investment Comparison
| Factor | HPS | LED |
|---|---|---|
| Upfront Cost (600W equivalent) | £150-300 | £400-800+ |
| Complete Setup Requirements | Bulb, ballast, reflector, cooling | LED fixture only |
| Initial Setup Complexity | Higher (multiple components) | Lower (single unit) |
HPS systems typically have a significantly lower upfront cost, making them more accessible for beginners or those on a tight budget. However, the complete setup requires more components and planning.
Ongoing Operational Costs
| Factor | HPS | LED |
|---|---|---|
| Electricity Consumption | Higher (600W actual draw) | Lower (250-300W for equivalent output) |
| Monthly Electric Cost (12hr/day) | £65-80 (600W) | £30-40 (equivalent output) |
| Bulb Replacement | Every 10,000-12,000 hours (£30-50) | 50,000+ hours (rarely needed) |
| Cooling Requirements | Significant (extraction fans, possibly AC) | Minimal (basic ventilation) |
| Cooling Costs | £10-30/month additional electricity | Minimal to none |
While HPS has a lower upfront cost, the ongoing operational expenses are significantly higher. Most growers find that LED systems pay for themselves within 1-2 years through electricity savings alone.
Return on Investment Timeline
Based on a 600W HPS vs. equivalent LED system running 12 hours daily:
- Additional upfront cost for LED: Approximately £300-500
- Monthly savings with LED: Approximately £35-50 in electricity
- Bulb replacement savings: £30-50 annually
- Cooling cost savings: £10-30 monthly
- Break-even point: Typically 8-14 months
Performance Comparison
| Factor | HPS | LED |
|---|---|---|
| Light Spectrum | Limited (yellow-red dominant) | Customizable (full spectrum available) |
| Canopy Penetration | Excellent | Good (improving with newer models) |
| Heat Output | High (can be problematic) | Low (beneficial in most cases) |
| Plant Stretching | More pronounced | Less pronounced |
| Yield Potential | 1-1.5g/watt (experienced growers) | 1.5-2g/watt (with quality fixtures) |
Practical Considerations
Space Constraints
In small grow tents (especially 4×4 or smaller), the heat from HPS can be challenging to manage. LEDs typically allow for easier temperature control in limited spaces.
Seasonal Adaptability
Some growers use HPS in winter (when the heat is beneficial) and switch to LED in summer (to reduce cooling needs). This hybrid approach maximizes the benefits of both technologies.
Growing Experience
Many experienced growers who have perfected their techniques with HPS lights are hesitant to switch, as it would require adjusting feeding schedules, watering practices, and environmental parameters.
The Bottom Line
The choice between HPS and LED ultimately depends on your specific circumstances:
- Choose HPS if: You're on a tight initial budget, grow in a cold environment where heat is beneficial, or have extensive experience with HPS and prefer not to change your growing style.
- Choose LED if: You're concerned about long-term electricity costs, grow in a space with limited cooling options, want more control over spectrum, or are starting fresh without established HPS growing techniques.
Both technologies can produce excellent results when used correctly. The "best" choice is the one that aligns with your specific growing environment, budget constraints, and personal preferences.