Electricity is the largest ongoing cost in indoor hydroponic growing, and in Australia it has become significantly more expensive over the past few years. Average residential rates across Victoria, New South Wales, Queensland, and South Australia now sit between 28 and 38 cents per kilowatt-hour depending on provider and tariff.
For a standard hobby grow room running a 600W HPS, extraction fans, water pumps, and environmental controls, monthly electricity costs can easily reach $80 to $150. For more serious setups, considerably more.
This guide covers the most effective ways to reduce those costs without reducing yield.
Where the Electricity Actually Goes
Before making changes, it is worth understanding what is actually drawing power in a typical grow room.
Grow lights account for the largest single load in most setups. A 600W HPS running 12 hours per day consumes 7.2 kilowatt-hours daily. At 32 cents per kWh that is $2.30 per day for the light alone, or roughly $70 per month for a single 10-week cycle.
Extraction and circulation fans are typically the second largest load. Inline fans range from 100 to 500 watts depending on size and speed. Running a 250W inline fan continuously consumes 6 kilowatt-hours per day.
Water pumps in recirculating systems, air pumps in DWC setups, and environmental controllers add smaller but consistent loads that accumulate across a full cycle.
Heaters and dehumidifiers add significant load when they run, and their runtime varies considerably by season. An Australian winter grow requiring several hours of heating per day can add $30 to $50 to a monthly bill unexpectedly.
Step One: Switch to LED if You Are Still Running HPS
The most impactful single change any HPS grower can make is upgrading to LED. No other change delivers comparable electricity savings.
A 600W HPS delivers approximately 1.7 to 1.9 µmol/J. The SANlight EVO Series operates at above 3.0 µmol/J. A SANlight EVO delivering equivalent photon output to a 600W HPS consumes roughly 280 to 300 watts, a saving of approximately 300 watts per light.
Running that saving across a 12-hour photoperiod saves 3.6 kilowatt-hours per day. At 32 cents per kWh that is $1.15 per day, or around $35 per month, per light. Over a full year with multiple cycles, the electricity saving alone covers a significant portion of the LED upgrade cost.
The secondary saving is equally important. HPS generates substantial heat that must be removed by the extraction system. Reducing the heat load in the tent means the extraction fan runs at lower speed for longer periods rather than at maximum capacity. This reduces fan electricity consumption and extends equipment lifespan.
Step Two: Use EC Motor Fans with Climate Controllers
Standard AC inline fans run at fixed speed. They consume their rated wattage whether the tent needs full extraction or not. EC motor fans are electronically variable and consume only as much power as the current speed setting requires.
Running an EC fan at 60 percent speed consumes significantly less than 60 percent of its rated wattage. The relationship between speed and power consumption in EC motors means meaningful electricity savings during periods when full extraction is not needed.
Pairing an EC fan with a climate controller that adjusts speed based on temperature and humidity is the efficient approach. The GAS EC5 Fan Controller adjusts fan speed reactively based on temperature, running the fan only as hard as conditions require rather than at a constant maximum.
The combined effect of a lower-wattage EC fan running at variable speed based on actual demand produces meaningful reductions in fan electricity consumption across a full grow cycle.
Step Three: Use Timers Precisely
Every hour of unnecessary runtime adds to the electricity bill. Lights, pumps, fans, and dehumidifiers all need to run on schedules matched to actual plant requirements rather than running on assumptions or convenience.
Digital timers allow precise scheduling of all electrical equipment. The JBL Digital Timer and Nakajima Digital Timer provide programmable scheduling for lights, pumps, and any other equipment that does not need to run continuously.
For recirculating drip systems, running the pump on timed cycles rather than continuously reduces pump runtime and associated electricity consumption without affecting plant nutrition. Most drip systems can run several feeding cycles per day rather than continuously and achieve the same results with lower electricity use.
Step Four: Insulate Your Grow Space
A poorly insulated grow room loses heat in winter and absorbs ambient heat in summer. Both increase the load on climate management equipment and add to electricity consumption.
Lining walls with reflective material, ensuring grow tents are positioned away from direct sunlight and external walls that heat significantly in summer, and managing where exhaust air goes all reduce the environmental management load.
In winter, a well-insulated grow room retains the heat produced by lighting and equipment, reducing or eliminating the need for supplemental heating. In summer, blocking heat ingress reduces cooling requirements.
Step Five: Match Your System Size to Your Actual Needs
Running a large system at partial capacity is inefficient. A 600W light in a 60x60cm tent wastes most of its output on tent walls. A large recirculating system growing a few plants runs pumps and air systems sized for a much larger load.
Correctly sized equipment runs more efficiently. A light matched to its footprint, a fan matched to the tent volume, and a pump matched to the system size all consume only the electricity needed for the task rather than excess capacity running at partial load.
Step Six: Consider Your Electricity Tariff
Many Australian households are on flat-rate electricity tariffs where all usage costs the same per kilowatt-hour. Time-of-use tariffs charge different rates depending on the time of day, typically lower rates during overnight and off-peak periods.
For growers who can run lights and pumps during off-peak hours, time-of-use tariffs can reduce electricity costs by 30 to 50 percent on those loads without changing anything about the grow itself. This typically means running lights at night rather than during the day, which has the additional benefit of shifting heat generation to cooler overnight periods during Australian summer.
Check with your electricity provider whether time-of-use tariffs are available in your area and what the rate differential is. For high-consumption setups, the savings can be significant.
Calculating Your Current Running Costs
A simple way to understand your current electricity consumption is to add up the wattage of every device in your grow room, multiply by the hours each device runs per day, and divide by 1000 to get kilowatt-hours. Multiply by your electricity rate to get daily cost.
Doing this before and after any efficiency change gives you the actual dollar saving rather than an estimate, and helps prioritise which changes deliver the best return.
For the full range of grow room equipment and energy-efficient lighting available in Australia, browse the Grow Lights and Environmental collections.