Room Heat-Load Estimate and Portable Heater Guide

Summary

This calculator provides a rough room heat-load range, not a heater purchase recommendation or a substitute for an HVAC load calculation. Portable electric heaters for a standard household outlet are commonly limited to about 1,500 watts. If the estimated range exceeds that capacity, do not add heaters or choose a higher-wattage portable unit based on this page; use a qualified HVAC professional or another properly installed heating solution.

Formula

room area x 10 W/sq ft x insulation factor x climate factor x ceiling factor

Data used

Calculator results use user-entered wattage and usage hours, combined with residential electricity rates for the selected U.S. state or the rate entered from a utility bill.

Sources

Limits

These estimates do not reproduce a utility bill. Actual costs depend on your tariff, taxes, appliance cycling, efficiency, and how you use the appliance.