Grow Light Electricity Cost Calculator

What the Calculator Estimates

This calculator estimates the electrical energy used by grow lights and multiplies it by the price paid for each kilowatt-hour. It is useful for comparing fixtures, photoperiods and room sizes before equipment is installed.

The result covers lighting only. Fans, pumps, air conditioners, heaters, humidifiers, dehumidifiers and controllers can add a substantial amount to total grow-room electricity use.

How Grow-Light Electricity Cost Is Calculated

A 600-watt fixture operating for 18 hours per day for 30 days uses 324 kWh. At $0.20 per kWh, its estimated lighting cost is $64.80.

Use Actual Power Draw

Marketing names and replacement-watt claims are not reliable inputs. Use the fixture’s listed input power at the selected dimmer level or measure draw with a suitable power meter. Drivers, controllers and conversion losses mean wall draw can differ from the nominal LED power.

Understanding Your Utility Rate

Electricity bills may include fixed charges, taxes, time-of-use pricing and tiered rates. A simple per-kWh price is most accurate when it reflects the additional energy used by the grow rather than the household’s average bill. If rates change by time of day, calculate each schedule segment separately.

Practical Ways to Compare Lighting Plans

• Compare actual wall draw at the same useful canopy coverage.
• Model vegetative and flowering photoperiods separately.
• Include every fixture when planning a multi-light room.
• Compare cost with measured PPFD distribution, not power alone.
• Leave capacity for climate-control equipment on the electrical circuit.

Limits of the Estimate

The calculator assumes constant power draw during the entered hours. Dimming schedules, sunrise and sunset ramps, controller standby use and voltage variation can change real consumption. It also does not assess circuit capacity or electrical safety. Permanent grow-room wiring should be evaluated by a qualified electrician under local rules.

Connect Cost with Delivered Light

Use the PPFD & DLI Calculator to relate energy use to the light delivered at the canopy. Browse the complete Cannabis Grow Calculators library for more tools.