Electricity Consumption (Efficiency)

High-Pressure Sodium (HPS) lights are inefficient when compared to LED. Up to 70% of the power is wasted as heat, you then need to expend more energy to remove this heat from your grow area. There is a direct equivalency between watts and heat, no matter which lighting source you use.

1 W = 3.412 Btu/h

So a 240W LED Board will generate the same amount of heat as a theoretical 240W HPS. The difference is that the quantum board will yield ~2-3x more. Typically, you would need to run a 600W HPS in the same space to approach the same yield. This often leads to overheating issues. Especially with DWC where maintaining cool water temperatures (max 68F) is essential to preventing root rot.

Yield

As mentioned above-LED lighting yields on average 2x more at a given wattage. With HPS lighting hitting 1g/watt was considered a milestone.

HPS Yield:

0.25-0.5 g/watt -Average

1.0 g/watt – Expert

LED Yield:

1.0 -1.6 g/watt – Average

2.0+g/watt – Expert

Note that the ‘expert’ values above typically involve the use of co2 supplementation and providing ideal growing conditions for your plants.



Cost of Startup

Electricity savings in the first grow will cover the negligible higher initial startup cost (approx $30). You can use my electricity calculator to determine your annual electricity costs to compare. I will compare a 600W HPS with a 240W LED board as they should yield approximately the same amount.

600w HPS cost = $130 USD on Amazon (free shipping)

240W LED Board = 100 + 40 Shipping + 30 Duties

240W LED Board = $170 USD (via Alibaba)

As you can see the price difference for equivalent producing HPS and LED lights is only about $30 USD. In Ontario, Canada the cost of electricity (off-peak) is $0.107/kWh.

You save 340 kWh by using an LED Board over an HPS light in the example above. At $0.107 kWh it would take only 2 months of running the lights to reach your break-even point where LED is more economically viable. Over a 1-year period, you would save $164 by running an LED Board over an HPS light at the 240W LED/600W HPS level.