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

A 2000-watt solar generator can run 1800-watt for around 29 minutes. It can run for longer when the solar generator is hooked to solar panels. 

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 Solar Generator to Power a space heater

A typical space heater will use between 1000 and 3000 watts, depending on the model. A low-wattage unit will be fine if you’re just looking to warm up a small area. A high-wattage unit will produce more heat but might take longer to do so because it takes more energy to get 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. 

Inverter for your space heater

All of this will be running through an inverter so you need to ensure you have an inverter that can power 1500 watts. This will require at least a 2000-Watt inverter. 

How Long Will a 2000-Watt Solar Generator Run a 1500-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. 

A 2000-watt solar generator will have a 24v 100Ah battery. With a lithium-ion battery, you can pull 50% of the battery in an hour. This means you can operate at a max of 50 amps at a voltage of around 21V. This means the solar generator can only provide a maximum of 1050 watts per hour or 1050 watts per hour. 

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. You can make a lot of coffee with the same power.

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

A 100Ah 24V battery will need 25 amps of DC power to charge. A 600-watt Solar panel can provide 25 amps 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 an extra 25 amps going to the battery, this adds to the capacity of our battery you can now pull 75 amps from the battery.  This now provides you with around 1500 watts of power per hour. 

With 1500 watts available:

= (1500*0.85)/1800 

= 0.70 hrs

The solar generator will last around 42 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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