Can A Generator Run A Heater?

During cold winter days, a space heater or an AC unit can make a huge difference between being comfortable or feeling miserable.

When being off-the-grid for whatever reason, when camping, during blackouts, or some other emergencies, staying warm is one of the most important things, so many people wonder if they can plug a space heater into a power or solar generator.

Published: January 5, 2023.

Generator Power vs. Space Heater Power

Space heaters come in various sizes with various nominal power.

Most popular heaters require 1500-2000 Watts max. and come with variable input power (usually 2-3 settings) and often with a safety switch - if the heater flips over, it automatically turns itself off.

Thus, to power a 1500W heater, a power generator of at least 2000 Running Watts is recommended, and to power a 2000W heater, a power generator with 3000 Running Watts is recommended.

When running space heaters and power generators, one must adhere to safety instructions from their manufacturers:

• Space heaters can be run indoors, but they should not be covered, and any flammable material around them should be removed. For more details on running your space heater, check its Owner's Guide.
• Power generators must be run outdoors, at a certain distance from doors and windows, to prevent the buildup of toxic Carbon Monoxide (CO) gas. During bad weather, snow or rain, power generators can be run outside, but they must be protected from rain and snow with a generator tent or similar generator enclosure. For more details on running your power generator, check its Owner's Guide.

Note: Propane heaters are operated indoors, but the area must be thoroughly ventilated. One propane tank/bottle will heat the area more if it is used to power a propane heater than if it is used to power a dual-fuel power generator that provides the electricity to run an electric space heater. Call me biased, but I really don't like the idea of having a propane heater indoors, even if it features a Carbon Monoxide sensor with an automatic shut-off system...

However, during a power outage, if You want to keep your home warm, You can start your power generator and use the electricity to power a space heater or, preferably, an AC unit.

Why?

Well, for every Watt of electricity, a space heater warms the area with 1W of heat. On the other hand, an AC unit with a heat pump/inverter warm the area with more than 1W, sometimes much more, depending on the energy efficiency class of the AC unit.

Just be aware that the AC unit also have Starting Watts that are much stronger than Running Watts, and your power generator must be able to support that.

For more on this topic, feel free to check the following articles:

• Off-the-Grid: How Much Electricity Does a Space Heater Use?
• Battery Operated Heater - Can a Battery Power a Tent or RV Heater?
• Watts to BTU and BTU to Watts Conversions
• How To Make Generator Quiet?

Power Generator vs. Solar Generator

Power generators convert chemical energy from fossil fuel into DC and AC electricity, while solar generators/power stations convert the energy stored in the onboard or external batteries convert into DC and AC electricity, which can be used to power space heaters and other loads.

In these examples, we will use WEN 56380i Super Quiet 3800-Watt RV-Ready Portable Inverter Generator and Jackery Explorer 1500 Portable Power Station (Amazon affiliate links, open in the new windows).

WEN 56380i Super Quiet 3800-Watt RV-Ready Portable Inverter Generator

WEN 56380i features 3400 Running Watts and 3800 Starting Watts, and with 2.2 gallons fuel tank, it features 8.5h runtime @50% load (1700W).

The list of receptacles includes two 120V 15A AC 5-20R, 120V 30A AC TT-30R, and 12V DC and 5V USB ports.

So, WEN 56380i is able to power a 1500W space heater for at least 9h continuously.

Actually, WEN 56380i can power two such units since each of its 120V 15A AC 5-20R receptacles can provide enough power.

Of course, in that case, the runtime is shorter.

Note: just like any power generator, WEN 56380i also must be run outside, away from doors and windows - before running WEN 56380i or any power generator, be sure to read its manual thoroughly.

And when the fuel tank is empty, one has to fill it again.

Jackery Explorer 1500 Portable Power Station

Jackery Explorer 1500 onboard battery stores up to 1534Wh of energy thanks to its 25.2V 60.9Ah lithium battery.

Jackery Explorer can be recharged in numerous ways, and thanks to the supported pass-through charging, the unit can be recharged and can power external loads at the same time.

For example, Jackery Explorer 1500 can be fully recharged using 4x100W solar panels in 5-10 hours and can power external loads up to 1800W.

So, it can power a 1500W heater on average up to ~50 minutes, not more.

But, Jackery Explorer 1500 can be used indoors, while solar panels are outside, making it ideal for camping, RV, in emergencies, and similar.

If You want to run a 1500W space heater using batteries, You will need plenty of batteries or one large battery pack.

Long Story Short: Yes, power generators can be used to power space heaters for many hours, depending on the power generator size and fuel tank capacity.

But, the power generators must be operated outside and when the fuel tanks get empty, they can be refueled in minutes. And if there is a fuel shortages, there isn't much a user can do with them.

Solar generators can be used to power space heaters, but for a relatively short period of time, after which they can be recharged using AC power (wall outlet or from power generator), car cigarette lighter port or using solar panels.

When charging with solar panels, direct sunlight is recommended, but good solar panels can provide at least some power even on a cloudy day.

So, power generators and solar generators don't compete between each other, they complement each other.

Note: All these devices must be used and operated as instructed by their manufacturers.