Radiant Heater Floor Load Calculator

Estimate incident radiant heat load across an X × Y grid below an evenly spaced array of electric infrared heaters. Select an Infratech heater model to automatically load its physical and electrical specifications.
Selecting a preset automatically loads the heater dimensions, wattage, voltage and amperage.
Model geometry represents the heater face dimensions used by the radiant calculation. The calculation assumes 90% radiant efficiency, uniform Lambertian emission, horizontal heater and target planes, no reflected radiant contribution, and no wind correction. Heater outputs from multiple fixtures are additive.

Calculated Radiant Load — W/ft²

Press Calculate.

Raw JSON Array

Press Calculate.

This radiant heater calculator is designed to help visualize how evenly infrared heat is distributed across a space before installation. It estimates the radiant heat load at a grid of points throughout the room and displays the results as both a shaded heat map and a numerical table in watts per square foot.

To use the tool, enter the room dimensions, the distance from the heater face to the target plane, the number of calculation points you want across the X and Y directions, and the number and arrangement of heaters. You can select a preset Infratech heater model from the dropdown, which automatically fills in the heater’s dimensions and wattage, or choose a custom heater and enter your own values.

After clicking Calculate, the tool distributes the heaters evenly across the selected number of rows and calculates the estimated radiant contribution from each heater at every point in the grid. The colored table makes it easy to see hotter and cooler areas at a glance, while the summary section shows the minimum, maximum, average, and uniformity of the calculated heat distribution.

This tool is intended primarily for comparing heater layouts, wattages, quantities, and mounting heights. It can be especially useful for evaluating whether a larger number of lower-wattage heaters may provide more even coverage than fewer higher-wattage units.

The results are engineering estimates based on a simplified radiant heat model. Actual performance can vary based on heater reflector design, mounting angle, wind, surrounding surfaces, outdoor conditions, and other site-specific factors. Final heater selection and installation should always follow the manufacturer’s recommendations and applicable electrical and building codes.