How Much Heat Does a Radiant Space Heater Produce?

Radiant space heaters are a popular choice for supplemental heating, offering a unique and energy-efficient way to warm up a room or targeted area. These heaters produce heat through infrared radiation, which travels in invisible, electromagnetic waves and gets absorbed by objects and people directly in their path. But just how much heat can a radiant space heater produce? Let’s dive into the details.

Understanding Radiant Heat Output

The heat output of a radiant space heater is typically measured in watts or British Thermal Units (BTUs). Most residential radiant space heaters for supplemental use have around 1,500 watts of power, which is equivalent to approximately 5,100 BTUs.

However, the exact heat output can vary depending on the manufacturer, model, and size of the heater. Larger radiant space heaters designed for primary heating in larger spaces can have outputs ranging from 10,000 to 15,000 BTUs, while smaller, portable models may be in the 3,000 to 5,000 BTU range.

To determine the appropriate heat output for your space, it’s generally recommended to choose a radiant space heater with around 10 watts (or 34 BTUs) of energy per square foot of the area you want to heat. This guideline can help ensure the heater has sufficient power to effectively warm the desired space.

Factors Affecting Heat Output

how much heat does a radiant space heater produce

The actual heat output of a radiant space heater can be influenced by several factors, including:

  1. Room Size and Layout: Larger rooms or spaces with high ceilings may require a more powerful radiant heater to achieve the desired level of warmth. The layout of the room, including the placement of furniture and other obstacles, can also affect the heater’s ability to distribute heat evenly.

  2. Insulation and Drafts: Well-insulated spaces with minimal drafts will retain heat more efficiently, allowing a radiant heater to maintain a comfortable temperature with less energy output. Poorly insulated rooms or those with drafty windows and doors may require a higher-powered heater to compensate for heat loss.

  3. Heating Needs: The specific heating needs of the space and its occupants can also impact the required heat output. For example, a room used for sedentary activities may require less heat than a space where people are more active and generating their own body heat.

  4. Energy Efficiency: Radiant space heaters are generally more energy-efficient than convection heaters, as they directly heat objects and people rather than relying on warming the surrounding air. However, the energy efficiency of a radiant heater can still vary depending on the specific model and its features.

Maximizing Radiant Heater Efficiency

To get the most out of your radiant space heater and ensure it’s producing the optimal amount of heat, consider the following tips:

  1. Choose the Right Size: Select a radiant heater with a heat output that matches the size of the space you want to heat, using the 10 watts per square foot guideline.

  2. Placement and Positioning: Position the heater in a location that allows for unobstructed heat distribution, and avoid placing it too close to walls or furniture.

  3. Insulation and Weatherproofing: Ensure the room is well-insulated and any drafts are addressed to minimize heat loss and maximize the heater’s efficiency.

  4. Thermostat Integration: Use a programmable thermostat to automatically adjust the heater’s output based on your heating needs and schedule, helping to optimize energy usage.

  5. Regular Maintenance: Keep the heater clean and well-maintained to maintain its optimal performance and safety.

By understanding the heat output capabilities of radiant space heaters and considering the various factors that can influence their efficiency, you can make an informed decision and ensure your supplemental heating needs are met effectively and energy-efficiently.


  1. Shiptons Heating & Cooling Inc., “What is a Radiant Heater and When Should You Use One?”
  2. Wattco, “Radiant Heaters Versus Convection Heaters”
  3. The Spruce, “The 9 Best Radiant and Convection Space Heaters of 2024, Tested and Reviewed”
  4. NewAir, “What’s More Effective: Convection or Radiant Heating?”
  5., “JASUN Portable Space Heater Electric Radiant Heater”