Infrared Heater Wattage for Generator Sizing
About the Infrared Heater
An infrared space heater that uses quartz or carbon heating elements to provide radiant warmth. Like other resistive heaters, there is no starting surge. Infrared heaters are particularly efficient in drafty spaces because they heat objects and people directly rather than heating the air. This makes them a good choice for generator-powered heating in garages, workshops, and older homes with poor insulation.
Generator Sizing for a Infrared Heater
Running a infrared heater by itself requires a generator with at least 1,875 W of capacity (2 kW), which includes a 25% safety margin. However, you rarely run a single appliance on a generator. When combined with other appliances, the infrared heater contributes 1,500 W to the continuous running load.
The infrared heater is a resistive load, meaning it uses a heating element or simple electronic circuit rather than a motor. Resistive loads draw the same wattage from the moment they turn on until they turn off, with no starting surge. This makes them the easiest type of appliance to run on a generator. When calculating your total generator load, the infrared heater adds a flat 1,500 W to your running total with no impact on peak surge calculations. Resistive loads also produce a power factor of 1.0, meaning they use electricity very efficiently with no wasted reactive power.
To determine the total generator size you need, use our interactive calculator to combine the infrared heater with your other appliances. The calculator automatically handles the starting surge calculation and applies the 25% safety margin to give you an accurate recommendation. Alternatively, browse the scenarios below to see common generator setups that include the infrared heater.
Tips for Running a Infrared Heater on a Generator
Running a infrared heater on a generator is straightforward since it is a purely resistive load. There are no special starting procedures or surge considerations. Simply ensure your generator's continuous (rated) wattage exceeds 1,500 W plus the wattage of all other appliances running simultaneously.
Since the infrared heater draws a constant 1,500 W whenever it is operating, you can accurately predict generator fuel consumption. At typical generator fuel efficiencies, running the infrared heater continuously adds approximately 0.1 gallons of gasoline per hour to your fuel consumption. If the infrared heater operates intermittently (like a thermostat-controlled heater), the actual fuel impact will be lower.
For sensitive electronic components within the infrared heater, an inverter generator provides the cleanest power output. However, most resistive appliances work fine on conventional generators as well. If you are running the infrared heater along with sensitive electronics like computers, the inverter generator protects all connected devices.
Infrared Heater Wattage Compared to Similar Appliances
The following table compares the infrared heater to other appliances in the hvac & climate category. Understanding relative power requirements helps you make informed decisions about which appliances to prioritize on your generator and where you might find opportunities to reduce your total load.
| Appliance | Running Watts | Starting Watts |
|---|---|---|
| Infrared Heater (this appliance) | 1,500 W | — |
| Central Air Conditioner (3-Ton) | 3,500 W | 4,500 W |
| Window AC Unit (5,000 BTU) | 500 W | 600 W |
| Window AC Unit (10,000 BTU) | 1,200 W | 1,500 W |
| Portable Space Heater | 1,500 W | — |
| Furnace Blower Fan | 800 W | 1,300 W |
| Whole House Fan | 500 W | 800 W |
Frequently Asked Questions
How many watts does a infrared heater use?
A infrared heater uses approximately 1500 watts of continuous (running) power during normal operation. As a resistive load with no motor, it has no starting surge above its running wattage.
What size generator do I need to run a infrared heater?
To run a infrared heater by itself, you need a generator rated for at least 1,875 W (2 kW), which includes a 25% safety margin above the running wattage of 1500W. However, most people run additional appliances alongside the infrared heater, so your actual generator needs will be higher. Use our calculator to add your other appliances and get a comprehensive recommendation.
Can I run a infrared heater on an inverter generator?
Yes, a infrared heater runs perfectly well on an inverter generator. As a resistive load with no motor starting surge, it is one of the easiest appliances to power with any generator type. The clean sine wave output of an inverter generator is a bonus for any electronic components.