Grow Room AC and BTU Calculator

Estimate electrical heat load

Nearly all electricity used inside a grow room eventually becomes heat. Enter actual grow-light draw and the combined power of fans, pumps, dehumidifiers, and other equipment. The calculator converts watts to BTU per hour and adds the selected margin.

The default 1,300-watt load produces about 4,436 BTU/h before margin. Adding 20% creates an estimate of roughly 5,323 BTU/h.

What this estimate includes

The result covers sensible heat from entered electrical equipment. It does not fully model solar gain, warm outside air, wall and ceiling conduction, occupants, duct losses, or the latent load created when moisture is removed from the air.

Why real AC sizing can differ

Room insulation, outdoor climate, ventilation, operating schedules, equipment location, and dehumidification all change demand. A vented fixture or equipment installed outside the room may transfer less heat indoors. Portable AC ratings can also differ from delivered performance.

Planning guidance

• Use measured power rather than marketing equivalents.
• Include equipment that releases heat inside the conditioned space.
• Consider peak simultaneous load, not only averages.
• Have electrical and HVAC work reviewed by qualified professionals.

This is an initial sensible-load estimate, not a substitute for a complete HVAC calculation or equipment specification.