Can a Solar Generator Run a Space Heater

A space heater will help you to keep your home warm during the cold winter months. However, space heaters consume a lot of power. A typical space heater will use between 1000 and 3000 watts, depending on the model.

A low-wattage unit will use 1800 Watts of power be fine if you’re just looking to warm up a small area. You can make a lot of coffee with the same power.

A Portable Solar Generator is an ideal power source for powering appliances during an emergency or when off-grid. But can it run a space heater?

In this article, we take you through how to choose a solar generator for your space and how you can use it to run your space heater for longer periods. 

What Size Portable Solar Generator to Power a space heater

An 1800-watt space heater will produce more heat in a small room from room temperature up to 70°F or whatever temperature setting you’ve set.  You will need 10 watts of heating power for every square foot of floor area in a room. 

So what size solar generator will you need?

To choose the right solar generator you first need to consider the inverter rating. All of this will be running through an inverter so you need to ensure you have an inverter that can power 1800 watts. This will require at least a 2000-Watt inverter.

To run a 1800-watt Space heater you will need a 2000-watt solar generator.

How Long Will a 2000-Watt Solar Generator Run an 1800-Watt Space Heater?

Electrical energy is measured in watt-hours. One watt-hour equals one watt expended for one hour. The number of watt-hours used by an appliance over a period of time equals the total amount of power consumed by that device over that period. 

To calculate watt-hours, multiply the watts used by an appliance over a period of time by the number of hours that appliance is used. If you use an 1800 Watt space heater for 1 hour, it will consume about 1800 watt-hours. 

To calculate the running time of a space heater, you would use the following formula:

Running Time = Solar Generator Watt-hours/operating power of the device 

We use 0.85 to factor in the efficiency losses due to conversion from the Inverter. 

For example to get the running time for a 1500-watt space heater

= (1050*0.85)/1800 

= 0.49 hrs

A 2000-Watt Solar Generator can run the space heater for around 29 minutes. 

How Long Will the Solar Generator Last with a 600-watt Solar Panel

A 600-watt Solar panel can provide 2400 watt-hours to fully charge the battery in around four hours. This will depend on the availability of sunlight. 4 hours of sunlight in an ideal situation should provide 2400Wh enough to recharge the solar generator. 

With 600 watts available:

= (600*0.85)/1800 

= 0.28 hrs

The solar generator will add around 17 minutes with the space heater with a 600-watt solar panel hooked to it.

Since we already have a figure when using the space heater for an hour for 30 minutes we can half the power use and for 15 minutes we half it again. 

Length in timeWatt-hour Requirements
1 hr1800Wh
30 minutes900Wh
15 minutes450Wh


In case of an emergency and you using your solar generator to run a space heater, rather than using a space heater over the course of a full hour, you can opt to heat your room over intervals of a few minutes. Some space heaters come with this feature already pre-installed and will warm up a room at different settings over a period of time. The timer enables you to set a time for the heater to come on so that you don’t enter a cold room. Likewise, it shuts down at the desired time when you leave the room.

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