Grow Room 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.

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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.
Total kWh/day 0.00 kilowatt-hours
Cost / Day $0.00 per day
Cost / Month $0.00 per month
Cost / Year $0.00 per year
How to use this calculator
  1. Enter your electricity rate — find it on your utility bill (look for ¢/kWh). US average is ~$0.13/kWh.
  2. 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.
  3. Watch the totals update live — the four cost tiles at the bottom update every time you change a value.
  4. Optional TOU pricing — expand "Advanced: Time-of-Use" and enter your peak rate and peak run hours for a more accurate bill estimate.
  5. 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 ▾
Add devices above to see the cost breakdown chart.

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.

Frequently Asked Questions

How much electricity does a grow room use?
A typical 4×4 grow tent with a 400W LED, fans, and a dehumidifier uses roughly 10–14 kWh per day, or $35–$55/month at $0.13/kWh. A 10×10 commercial room with 2,000W of lights, HVAC, and CO₂ can exceed 100 kWh/day — over $400/month. Use this calculator to find your exact number.

How do I calculate grow room electricity cost?
Multiply each device's wattage by its daily run hours, divide by 1,000 to get kWh/day, then multiply by your electricity rate. Repeat for all devices and sum the totals. Formula: kWh/day = (Watts ÷ 1,000) × Hours × Quantity. Monthly cost = kWh/day × rate × days per month. This calculator does all of that automatically.

What uses the most electricity in a grow room?
Grow lights typically account for 50–70% of total electricity in a grow room. HVAC (air conditioners and dehumidifiers) is usually the second-largest load at 20–35%. Fans, CO₂ equipment, and pumps make up the rest. The bar chart above shows exactly which devices dominate your bill.

How can I reduce my grow room electricity bill?
Switch to LED grow lights (50–60% less power than HPS/MH). Use programmable timers, run lights at off-peak hours if you have TOU billing, right-size your HVAC to your actual heat load, and use EC (electronically commutated) fans that ramp down automatically.

What is a Time-of-Use (TOU) electricity rate?
TOU pricing charges different rates for peak vs. off-peak hours. Peak hours (typically 4–9 PM) can cost 2–3× more than off-peak. Growers using timers can shift lights-on time to off-peak windows — for example, running 7 PM–1 PM instead of 6 AM–midnight — saving 20–40% on lighting costs. Use the Advanced TOU section above to model this.
⚡ Grow Room Device Power Reference Typical wattage ranges for common devices
Typical wattage, run hours, and monthly cost at $0.13/kWh for common grow room 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

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