Commercial LED Grow Lights - Case Study

PhytoMAX LED Grow Lights vs. 1000W HPS and DE HPS

Power Savings with Commercial LED Grow Lights

Fixture Power Savings

In a commercial setting, power savings are important to help reduce expenses and therefore maximize profits. Saving even 5% in overall power consumption is significant, and even more valuable when the changes can be made with no negative impact on yield or quality.

The following calculations take into account the power savings for lighting fixtures only, and do not reflect any savings on cooling, or much more importantly the additional revenue from increased yield.

% Reduction in Power Per LED Grow Light

In the case of the Black Dog LED grow lights being compared to the ducted single-ended 1000 watt HPS this reduction would be calculated as follows:

PhytoMAX 800 LED grow light vs. ducted 1000 watt single-ended HPS
PhytoMAX 800800 watts
Ducted HPS1025 watts
Difference between fixtures1025 watts – 800 watts225 watts
Percentage reduction in power use from HPS fixtures225 / 102521.9%
PhytoMAX 800 LED grow light vs. DE HPS
PhytoMAX 800800 watts
DE HPS1055 watts*
Difference between fixtures1055 watts – 800 watts255 watts
Percentage reduction in power use from DE HPS fixtures255 / 105524.2%

*1055 is the wattage the DE HPS were set to for the DE HPS run

Dollar Savings on Power for Commercial LED Grow Lighting

The lights were run on a standard flower cycle of 12 hours on per day. In this test case study the kWh cost assumption was $0.04947. To calculate the savings for the entire room over the flower period the following calculations are made using the following assumptions:

kWh cost$0.04947
Hours of light in 9 week flower cycle12 hours/day X 7 days/week X 9 weeks756 hours
PhytoMAX 800 LED Grow Light
Number of PhytoMAX 80012
Wattage800 watts
Convert to kilowatts800 watts / 1000 watts/kW0.8 kW
Total energy use12 lights X 0.8 kW X 756 hours7257 kWh
Total lighting power cost7257 kWh X $0.04947$359.00
Savings vs. Ducted single-ended HPS
Number of ducted HPS lights12
Wattage of ducted HPS1025 watts
Convert to kilowatts1025 watts / 1000 watts/kW1.025 kW
Total energy use12 lights X 1.025 kW X 756 hours9299 kWh
Total lighting power cost9299 kWh X $0.04947$460.02
Power savings for PhytoMAX 800 LED grow lights compared to 1000W ducted single-ended HPS over 9 week run$460.02 – $359.00$101.02
Savings vs. DE HPS
Number of DE HPS lights10
Wattage of DE HPS1055 watts
Convert to kilowatts1055 watts / 1000 watts/kW1.055 kW
Total energy use10 lights X 1.055 kW X 756 hours7976 kWh
Total lighting power cost7976 kWh X $0.04947$394.57
Power savings for PhytoMAX 800 LED grow lights compared to DE HPS over 9 week run$394.57 – $359.00$35.57

Conclusion on LED Grow Light Power Savings

When looking solely at the calculated lighting power savings for the room with different commercial lighting technologies, it is hard to justify the additional cost of LED grow lights in the commercial setting. If this were the only basis for making a decision, LED grow lights would likely not be the best choice- but we must look at the whole picture to determine the true revenue opportunity PhytoMAX LED grow lights provide. Cooling savings also impact the return on investment as can quality increases of the final product, but most importantly increased yield provides the critical ROI, since weight is the basis for any commercial Cannabis grow operation. To make a good decision founded on sound business principals, the entire operational impact of the lighting selection must be taken into account.

Cooling (A/C) Savings

Unfortunately the testing setup in this study doesn’t allow perfect determination of the cooling savings offered by running ambient temperatures 10 degrees warmer (85 Fahrenheit with PhytoMAX LEDs versus 75 Fahrenheit with standard HPS lights), but the savings can still be extrapolated fairly accurately. Physics dictates that any power (wattage) put into a closed space will result in heat, directly proportional to the amount of power (wattage) put in. For this study, the PhytoMAX 800 LED light fixtures always used less power than either the single-ended or double-ended HPS fixtures. However, the 12 PhytoMAX 800 LED grow lights used only 950 watts less than the 10550 total watts of the 10 DE HPS fixtures, making the difference in heat generation only (950 / 10550 = ) 9% when comparing these two setups.

Comparing savings in cooling costs is complicated by the fact that outdoor temperatures will affect the amount of cooling required. When outdoor temperatures are warmer than the grow room, the external heat will increase the temperature (and cooling requirements) of the grow room. Similarly, outdoor temperatures cooler than the grow room will decrease cooling requirements as heat from the grow room will naturally dissipate through the walls and ceiling of the facility. The larger the difference between the indoor and outdoor temperature, the larger the difference in cooling requirements will be. Insulation and building materials also have a significant impact on the difference in cooling requirements. Even opening the door to the grow room will affect cooling requirements, depending on the indoor temperature outside of the grow room.

This test tracked the outdoor average temperature, grow room average temperature and cooling costs on a daily basis to allow comparisons to be made as accurately as possible. To this end, cooling requirements are only compared for days which have identical outdoor temperatures.

Daily Cooling Power Requirements (kWh) when Outdoor Temperature is 66 °F
DE HPS (10550 total watts, 75 °F ambient) PhytoMAX 800 (9600 total watts, 85 °F ambient)
32.8 17.7
34.3  
32.7  
34.1  
Average
33.5 17.7

Daily Cooling Power Requirements (kWh) when Outdoor Temperature is 64 °F
DE HPS (10550 total watts, 75 °F ambient) PhytoMAX 800 (9600 total watts, 85 °F ambient)
33.8 10.7
Average
33.8 10.7

Daily Cooling Power Requirements (kWh) when Outdoor Temperature is 62 °F
DE HPS (10550 total watts, 75 °F ambient) PhytoMAX 800 (9600 total watts, 85 °F ambient)
31.7 8.9
36.1  
16.3  
Average
28.0 8.9

Daily Cooling Power Requirements (kWh) when Outdoor Temperature is 59 °F
DE HPS (10550 total watts, 75 °F ambient) PhytoMAX 800 (9600 total watts, 85 °F ambient)
30.0 11.0
23.6 10.0
  15.0
Average
26.8 12.0

Daily Cooling Power Requirements (kWh) when Outdoor Temperature is 53 °F
DE HPS (10550 total watts, 75 °F ambient) PhytoMAX 800 (9600 total watts, 85 °F ambient)
28.7 13.2
Average
28.7 13.2

Daily Cooling Power Requirements (kWh) when Outdoor Temperature is 50 °F
DE HPS (10550 total watts, 75 °F ambient) PhytoMAX 800 (9600 total watts, 85 °F ambient)
28.3 3.0
Average
28.3 3.0

Average Cooling Power Requirements per Day
Outdoor Temperature DE HPS (10550 total watts, 75 °F ambient) average PhytoMAX 800 (9600 total watts, 85 °F ambient) average
66 °F 33.5 kWh 17.7 kWh
64 °F 33.8 kWh 10.7 kWh
62 °F 28.0 kWh 8.9 kWh
59 °F 26.8 kWh 12.0 kWh
53 °F 28.7 kWh 13.2 kWh
50 °F 28.3 kWh 3.0 kWh
Average
59 °F 29.9 kWh daily 10.9 kWh daily
Loading graph…
This graph shows relative cooling power requirements between DE HPS and PhytoMAX 800 lights.

In all comparable cases above, the outdoor temperature was less than the grow room temperature, which will decrease the cooling needs for both the DE HPS and LED grow lights. On average the LED-lighted room at 85 °F ambient temperature required 64% less energy to cool the same room with DE HPS fixtures at 75 degrees on days with the same average outdoor temperature. With outdoor temperatures higher than the grow room temperature, this difference will likely increase somewhat, but the 10 degree difference in ambient grow room temperature will still provide a significant savings,

It should be noted that air conditioning systems typically act as dehumidifiers for indoor grow rooms, and that decreased use of air conditioning may result in a need to run alternate dehumidification systems. The test facility was equipped with a 700 watt (0.7 kWh) dehumidifier whose actual total power consumption was unfortunately not monitored. For the absolute worst-case scenario where this dehumidifier was running at full capacity 24 hours per day:

Maximum Power Usage With Dehumidifier and Air Conditioning
Dehumidifier wattage (maximum)700 watts
Convert to kilowatts700 watts / 1000 watts/kW0.7 kW
Dehumidifier power usage per day (if run at full capacity 24 hours per day)0.7 kW X 24 hours16.8 kWh
Cooling power usage per day (average)10.9 kWh
Dehumidifier and air conditioning power usage per day16.8 kWh + 10.9 kWh27.7 kWh
DE HPS air conditioning power usage per day (average)29.9 kWh
Difference in cooling and dehumidification power use from DE HPS fixtures29.9 kWh – 27.7 kWh2.2 kWh
Percentage reduction in cooling and worst-case dehumidification power use from DE HPS fixtures2.2 kWh / 29.9 kWh9%

Next, lets examine how PhytoMAX LED grow lights perform in yield.