A grow room electricity calculator will help you develop realistic expectations for the costs of running your lights. On top of the initial setup costs of your grow tent, lights, ventilation equipment, CO2, and more, you need to consider the monthly cost of running these components.
The bulk of your monthly energy bill is going to come from running your grow lights, so our grow room electricity calculator will put a dollar figure to what you can expect to pay.
Do grow lights use a lot of electricity?
Grow lights don’t use as much electricity as you may think. If you have a smaller grow, you don’t need to set aside hundreds of dollars each month to run your grow lights. Due to increasing competition amongst grow light manufacturers, innovation is pushing efficiency further and further. These days, indoor growing is not as expensive as you'd think!
A light system will increase your electricity cost -- the exact amount depends on the size of the system and the number of hours operated. However, since most grow lights are so energy efficient, you are getting huge amounts of light (and growing power) for your money! Make sure your grow room's power circuit can handle the power draw. For safety reason, do not exceed 75% of the rated ability of the fuse/breaker (for example: use no more than 15 amps on a 20-amp circuit).
Do LED grow lights cost less to run?
LED grow lights may have the highest initial cost of all the lighting types, but they pay for themselves over time. These lights are the most efficient, and cost far less to run than MH/HPS and CMH, while providing arguably the highest performance.
On top of this, LED’s generate less heat than other grow lights. This cuts HVAC costs, further lowering your energy bill.
Understanding actual wattage vs manufacturer wattage for LED’s
It’s important that you understand not all wattages are created equal. LED’s put out superior light compared to other lighting types, and thus a 400 watt LED is not the same as a 400 watt metal halide light.
When shopping for grow lights, specifically LED, look at the actual wattage compared to the manufacturer’s stated wattage. Take the Gavita 1650 Pro LED, for example. You can see that the specifications of this light are 646 actual watts. However, according to Gavita this light is equivalent in performance to a 1000 watt HPS.
Grow room electricity calculator - find your monthly energy cost
Our grow room electricity calculator takes a few things into consideration when helping you determine what it will cost to run your grow lights. These include lighting type, the number of hours per day you run the light, your local electricity cost, and how many lights you run.
As mentioned earlier, not all lights run the same. An LED can be more than twice as efficient as HID grow lights. You may see different energy costs across all lighting types: LED, MH/HPS, CMH, and fluorescent.
Veg vs flower cycle
Another huge factor in your monthly grow light cost is how many hours per day you will run them. During veg, you will run your lights 18-24 hours per day, which will result in a higher monthly cost than during flower, where you only run your lights 12 hours per day.
Local energy cost
The final determinant in calculating your grow light electricity cost is what you actually pay for energy in your home or facility. For example, our local residential electricity cost is $0.1559 per kilowatt hour (kWh).
How many lights are you running?
This factor will have a compounding effect on your energy bill. Obviously you will pay more for running more lights, but this also raises other electricity costs. The more lights you run, the higher your cost of HVAC and ventilation will be.
Calculating your energy bill
To find the monthly cost of running your grow lights use this formula: Total Kilowatts x kWh x hours per day x 30 (days). You need to divide your wattage by 1,000 (1,000 kilowats in 1 watt). So, if we were to run a 1000 watt grow light 18 hours a day with the kWh rate we gave earlier, our formula would be: 1 x $0.1559 x 18 x 30 = $84.186/month.
How to lower your grow room electricity costs
There are a few ways you can cut your grow room electricity costs, ranging from simple tweaks to complete overhaul of your grow lights. Let's start with the easiest ways to lower your energy bill.
Run your lights during the least expensive time
Electricity costs range throughout the day, with the most expensive kWh costs being during the hottest parts of the day. You can try running your lights at night when the cost of energy is lower.
Choose an autoflower or fast growing strain
Autoflower strains and others with short harvest times can cut weeks off your growing cycle. This will obviously save you money on electricity, so choose a fast growing strain and grow them quickly!
Use more efficient grow lights
The best way to cut back on the cost of running your grow room is to use more efficient grow lights. LED grow lights have a higher initial cost, but actually end up paying for themselves over time. LED's also provide a more powerful light, with a superior spectrum.