Running an indoor cannabis garden brings rewards, but it also brings recurring expenses you can’t ignore. With rising electricity rates, inefficient lighting, or multiple devices running 24/7, your monthly power bill can add up quickly. That’s why we created the new Grow Room Electricity Calculator, designed to give you a clear, realistic estimate of your energy use and costs.
By entering your actual wattage (not just “advertised” watts), the number of hours/day you run your Grow Lights and other equipment, and your local electricity rate, you’ll see daily, monthly, and yearly costs at a glance. Whether you’re growing a few plants in a Grow Tent or managing a commercial facility, knowing your true cost helps you plan smarter and save money over time.
Grow Light Electricity Calculator
Grow Room Electricity Cost Calculator
Enter every device in your grow — lights, fans, HVAC, CO₂, pumps — and see your exact kWh usage and electricity cost per day, month, and year. Costs update live as you type. Need to upgrade your lighting? Talk to a Grow Expert.
Grow Room Electricity Calculator
Add devices below — kWh and costs update live as you type. Use the Advanced (TOU) section if your utility charges peak/off-peak rates.
⚡ Advanced: Time-of-Use (TOU) Pricing
TOU cost uses your peak rate for peak hours and standard rate for off-peak hours — applied proportionally per device.
| Device i Name your device (e.g. "LED Light 1"). Optional — for your reference only. | Watts i The running wattage, not the max. Check the device label or spec sheet. LED drivers often run at actual draw, not rated watts. | Hrs/Day i How many hours per day this device runs. Lights run 18h in veg, 12h in flower. Always-on devices like fans = 24. | Qty i Number of identical units. If you have 4 fans of the same wattage, enter 1 row with Qty = 4. | kWh/Day i Formula: (Watts ÷ 1,000) × Hours × Quantity. This row's contribution to your daily electricity use. |
|---|
How to use this calculator
- Enter your electricity rate — find it on your utility bill (look for ¢/kWh). US average is ~$0.13/kWh.
- Add your devices — use a preset or enter a custom row. For each device: enter wattage (from spec sheet or device label), daily run hours, and quantity.
- Watch the totals update live — the four cost tiles at the bottom update every time you change a value.
- Optional TOU pricing — expand "Advanced: Time-of-Use" and enter your peak rate and peak run hours for a more accurate bill estimate.
- Export your results — use Copy Results for a text summary, CSV Export for a spreadsheet, or Print for a paper copy.
Formula: kWh/Day = (Watts ÷ 1,000) × Hours/Day × Quantity · Monthly Cost = kWh/Day × Rate × Days
📊 Device Cost Breakdown — Bar Chart Visual ▾
Each bar represents one device row's daily electricity cost. Taller bars = bigger cost contributors — those are your best targets for efficiency upgrades. Hover or tap a bar to see the exact kWh and cost.
⚡ Grow Room Device Power Reference Typical wattage ranges for common devices
| Device | Typical Watts | Typical Hours/Day | kWh/Month (est.) | Cost/Month @ $0.13 |
|---|---|---|---|---|
| LED Grow Light (budget 2×4) | 150–200W | 18h | 81–108 kWh | $10–$14 |
| LED Grow Light (mid 4×4) | 240–320W | 18h | 130–173 kWh | $17–$22 |
| LED Grow Light (pro 4×4) | 480–630W | 18h | 259–340 kWh | $34–$44 |
| HPS 600W | 600–660W | 18h | 324–356 kWh | $42–$46 |
| HPS 1000W | 1,000–1,100W | 18h | 540–594 kWh | $70–$77 |
| Mini-Split AC (9,000 BTU) | 700–1,000W | 10–16h | 210–480 kWh | $27–$62 |
| Portable AC (8,000 BTU) | 900–1,200W | 10–16h | 270–576 kWh | $35–$75 |
| Dehumidifier (30-pint) | 250–350W | 24h | 180–252 kWh | $23–$33 |
| Dehumidifier (70-pint) | 600–800W | 24h | 432–576 kWh | $56–$75 |
| Inline Fan (6-inch) | 40–80W | 24h | 29–58 kWh | $4–$8 |
| CO₂ Controller/Solenoid | 20–30W | 24h | 14–22 kWh | $2–$3 |
| Water Pump (submersible) | 20–150W | 0.25–2h | 0.2–9 kWh | $0.02–$1.20 |
Ready to cut your electricity bill?
Upgrade to efficient LEDs, EC fans, and smart controllers — shop our full lineup.How Your Electricity Costs Add Up
Even though lighting is usually the largest energy expense, other devices contribute significantly.
- Grow Lights: The backbone of your grow room, but also the top electricity draw.
- Ventilation & Fans: Inline fans, oscillating fans, and exhaust systems run almost constantly.
- Climate Control: AC units, dehumidifiers, and heaters often equal or exceed lighting costs depending on your climate.
- Other Devices: CO₂ Injectors, Water Pumps, and Controllers may seem minor, but add up.
A good calculator should factor in all of these, not just the lights, to give a true picture of your monthly bill.
Key Factors That Drive Electricity Costs
Factor |
Why It Matters |
Example |
Actual Wattage |
Many LEDs advertise “equivalent” watts. Always calculate with true power draw. |
A “1000 W LED equivalent” may actually use 600 W. |
Hours per Day |
More runtime = higher cost. Veg often runs 18–24 hours/day, flowering ~12. |
600 W light × 18 h/day uses 10.8 kWh daily. |
Electricity Rate ($/kWh) |
Local rates and time-of-use pricing can make big differences. |
$0.12/kWh vs $0.20/kWh changes a bill by 40%+. |
Other Equipment |
Fans, AC, and dehumidifiers can raise bills 20–40%. |
A 1000 W AC unit running 12 h/day costs ~$43/month at $0.12/kWh. |
How the Grow Room Electricity Calculator Works
Using our tool is simple:
- Enter your local electricity rate ($/kWh).
- Choose days per month to calculate costs.
- Add each device: wattage, hours per day, and number of units.
- Instantly see your daily, monthly, and yearly electricity costs.
For advanced users, you can also factor in time-of-use rates to compare on-peak vs off-peak costs.
Example Electricity Costs for Different Grow Scenarios
Grow Setup |
Devices |
Rate ($/kWh) |
Hours/Day |
Monthly Cost |
|
Small 2’×2’ Tent |
150 W LED + fan |
$0.17 |
18 h |
~$15–18 |
|
4’×4’ Flower Tent |
600 W LED + fans + dehumidifier |
$0.17 |
12 h |
~$80–110 |
|
HPS Equivalent |
600 W HPS + same devices |
$0.17 |
12 h |
~$110–150 |
|
Commercial Room |
8 × 1000 W LEDs + AC + fans |
$0.12 |
12 h |
~$1,100–1,400 |
Ways to Lower Your Grow Room Electricity Bill
Since electricity is ongoing, even small improvements add up:
- Switch to LEDs: Modern high-efficiency LEDs provide more usable light per watt than HPS or CMH.
- Run Lights Off-Peak: If your utility offers cheaper rates at night, run your lights then.
- Shorter Cycles with Autoflowers: Fast-finishing strains mean fewer weeks of lights running.
- Efficient HVAC: Upgrade to energy-efficient AC and dehumidifiers.
- Reflective Surfaces: Mylar or flat white walls improve light use, reducing wasted energy.
- Timers & Controllers: Prevent unnecessary runtime with precise scheduling.
FAQs for Grow Room Electricity Calculation
Q: Why should I use actual wattage instead of advertised wattage?
A: Advertised wattage often inflates output by comparing to HPS systems. Your bill is based on actual power draw.
Q: How do I calculate electricity cost manually?
A: Formula = (Watts ÷ 1000) × Hours per Day × $/kWh × Days. For a 1000 W light running 18 h/day at $0.15/kWh for 30 days = $81/month.
Q: Do LEDs always cost less to run?
A: Almost always, yes. LEDs deliver higher efficiency and lower HVAC costs, but quality and spectrum matter.
Q: Does the calculator include non-lighting equipment?
A: Yes, you can add fans, AC, dehumidifiers, and more to see total costs.
Q: What’s the best way to reduce costs without hurting yield?
A: Upgrade to high-efficiency LEDs, optimize runtime for growth stage, and improve your climate control efficiency.
Final Thoughts: Grow Smarter, Spend Less
Electricity costs don’t have to be a mystery—or a drain on your grow’s profitability. With our Grow Room Electricity Calculator, you can finally get accurate estimates, compare lighting setups, and spot savings opportunities.
By using efficient fixtures, optimizing light schedules, and planning around your utility rates, you’ll reduce costs without sacrificing yield. That’s how you grow smarter—not more expensive.
🔗 Use the Grow Room Electricity Calculator Now