Electricity for lighting is often the most expensive part of growing marijuana indoors. Indoor growers tend to use HPS and MH bulbs both of which use relatively large amounts of electricity. Alice will have an advantage over Bob if she makes intelligent choices about her lighting fixtures, growing cycles, etc. Lower operating costs, higher profits.
Electric rates are often a fixed cost per kilowatt hour: cost in KWH x total wattage x hours
We encourage growers to use this spreadsheet caclulator to figure out what electricity will cost for a given set of lights. The time intervals (18 & 12 hours) represent common daylight cycles for growth and flowering respectively. This spreadsheet is useful when comparing different light sources (HPS, MH, CFL, LED, etc) or different lighting cycles. It’s a modest attempt to help growers use less electricity, save money, and reduce their carbon footprint.
If your plants are night owls they’ll help with load balancing. Ideally consumer demand should be even throughout the day but it isn’t. Most electricity is used during the daytime. Less of a utility’s generating capacity is used at night. Do your part by setting your timer so your lights come on when demand is low.
Different light cycles have an impact on your electric bill. See how much you’ll save by flowering at 11/13 vs 12/12, even when you account for a longer flowering time using a shorter daylight cycle.
The Cost of Light is free software released under a Creative Commons license (CC BY 4.0). Feedback is always encouraged. What else would you like to see it do?