Welcome back to Our Blue Ridge House. Today, in our series about generators, we’re going to tackle a question that’s quite timely, especially as we gear up for the cold winter months: “What size generator to run a space heater?” 

With power outages becoming increasingly common, having a reliable source of warmth is essential.


Let’s dive into this topic with a relaxed tone and cover all the essential information you need to know.

What Size Generator to Run a Space Heater | Factors to Consider

Selecting the right size generator to run a space heater is essential to ensure the safe and efficient operation of both the generator and the heater. 

The average size generator used to run a space heater is 2000 watts. However, there are factors to keep in mind when selecting a portable power station.

Here are the key factors to consider when determining the appropriate generator size for your space heater:

1. Space Heater Wattage

 The wattage of your space heater is the most critical factor. Check the heater’s label or user manual for its wattage rating. This information will help you understand the minimum running watts required for the size of your generator.

2. Total Wattage

If you plan to run multiple space heaters simultaneously or in combination with other electrical devices, add up their wattages to determine the total power requirements.

Make sure the generator’s running watts capacity can handle this total load.

3. Starting Watts

Keep in mind that most electrical appliances, including space heaters, have a starting wattage that is higher than their running wattage.

Ensure your generator can handle the initial surge of power needed when you turn on the space heater(s). This is especially important for devices with motors or compressors.


4. Safety Margin

It’s a good idea to choose a generator with a bit more capacity than just the minimum requirements. This provides a safety margin and prevents overloading the generator, which can damage both the generator and your appliances.

5. Other Electrical Devices

 Consider any other electrical devices or appliances you may need during a power outage. Include their wattage requirements in your total load calculation.

Common devices include lights, refrigerators, sump pumps, and electronic devices.

6. Extension Cord Length

If you plan to use extension cords to connect your space heater to the generator, be aware that longer cords can lead to voltage drops and reduced efficiency.

Choose a generator size that compensates for any voltage losses due to cord length.

7. Safety Considerations

Always prioritize safety. Avoid overloading the generator, and ensure it’s placed in a well-ventilated area if it’s a gas-powered generator.

Be cautious about carbon monoxide risks and follow safety guidelines.


8. Transfer Switch

Consider installing a transfer switch that allows you to connect the generator directly to your electrical panel. This way, you can power specific circuits in your home without the need for extension cords.

9. Generator Type

Decide whether you want a portable generator, standby generator, solar generator, or another type.

Each has its own capacity and features, so choose one that aligns with your needs and budget.

10. Fuel Type

The type of fuel your generator uses can impact its power output and fuel efficiency. Common options include gasoline, propane, natural gas, and diesel.

Choose a fuel source that suits your preferences and availability.

11. Duration of Use

Consider how long you expect to run the space heater(s) with the generator. If you anticipate extended power outages, you may need a larger generator or alternative heating sources.

12. Environmental Impact

If environmental concerns are important to you, explore options like solar generators or generators that can be powered with clean energy sources like natural gas.


By carefully considering these factors and calculating your specific power requirements, you can select the right size generator to run your space heater effectively and safely during power outages.

It’s always a good idea to consult with a professional if you have any doubts or if you need assistance with sizing your generator.

Powering Up Your Space Heater During a Power Outage

Finding the right size generator is crucial. If you get a generator that’s too small, it won’t provide enough power, and your space heater might not work correctly.

On the other hand, if you opt for a generator that’s too big, you could waste fuel and money.

If your intent is to only run a space heater, you will need a small generator that doesn’t run much power.

Safety Tips for Using Generators with Space Heaters


Safety should always be a top priority when using generators and space heaters:

Carbon Monoxide Risk: Never run generators or space heaters indoors as they produce carbon monoxide. Use them in well-ventilated areas.

Extension Cords: Ensure you’re using the right extension cords that can handle the generator’s power output.

Avoid Overloading: Don’t overload your generator by connecting too many devices. Check the generator’s capacity and stay within its limits.

Fuel Safety: If you’re using a generator that runs on fossil fuels, store fuel in a safe place away from flammable materials.

Consider a Transfer Switch: A transfer switch helps you connect the generator directly to your electrical panel, providing power to specific circuits in your home. It’s a safer and more efficient option than using extension cords.

Choosing the Best Generator for Your Needs

When it comes to picking the right generator size for your space heater, it’s not just about heating.

Think about other electrical devices you might need during a power outage, like lights, the refrigerator, a sump pump, or even a coffee maker for those early mornings.

Consider the surge wattage requirements of these appliances as well.


Why Use a Generator for Space Heaters?

The first thing you might wonder is why use a generator to power a space heater in the first place? Well, when the electrical grid goes down, so does your heating system.

That’s where a portable generator or a solar generator comes into play. It can provide you with the much-needed power to stay warm during an outage.

Understanding Generator Basics


Before we get into specifics, let’s talk about generator basics. Generators are rated in watts, which determine their power output.

You’ll often come across terms like “running watts” and “starting watts.”

Running watts refer to the continuous power a generator can provide, while starting watts account for the initial surge of power needed when an electrical appliance, like a space heater, is turned on.

Calculating Your Space Heater’s Wattage

The size of your generator depends on the size of your space heater.

Most electric space heaters come with a wattage rating that you can find on a label or in the user manual. For instance, a small space heater may require around 1500 watts, while a larger one could go up to 3000 watts.

Total Wattage Matters

If you plan to power multiple space heaters, add up their wattages to determine the total power requirements. For example, if you have two 1500-watt heaters, you’d need a generator with a capacity of at least 3000 running watts, plus some extra for starting watts.

Top 5 Portable Generators for Large Space Heaters

When selecting a portable generator to run a large space heater, you need to consider the wattage requirements of the heater. Moreso, you will want to ensure the generator can handle the load safely.

Here are five portable generators with different wattage capacities that can be used to power a large space heater:

  1. Champion 7500-Watt Dual Fuel Portable Generator (Model: 100165): This generator offers a substantial 7500 running watts on gasoline and 6750 running watts on propane. It’s versatile and can handle large space heaters with ease. The dual-fuel capability provides fuel options for convenience.
  2. Westinghouse WGen7500 Portable Generator: With 7500 running watts and 9500 peak watts, this generator is suitable for powering a large space heater. It features a 420cc Westinghouse 4-Stroke OHV engine and offers a good balance between power and portability.
  3. Briggs & Stratton P4500 Power Smart Series Inverter Generator: This inverter generator provides 4500 running watts, making it a reliable choice for running a large space heater. Its inverter technology ensures clean and stable power, which is crucial for sensitive electronic devices.
  4. DuroMax XP12000EH Dual Fuel Portable Generator: If you need a generator with a higher wattage capacity, the DuroMax XP12000EH is a beast with 9500 running watts on gasoline and 8500 running watts on propane. It can easily handle a large space heater along with other appliances.
  5. Honda EU2200i Super Quiet Inverter Generator: While not as powerful as some of the others on the list, the Honda EU2200i is known for its reliability and quiet operation. It provides 2200 running watts, which should be sufficient for most large space heaters. This generator is great for those who prioritize quiet operation and clean power.

Remember to consider the specific wattage requirements of your large space heater and any additional appliances you plan to power simultaneously when choosing the right portable generator.

Additionally, always follow safety guidelines and ensure proper ventilation when using portable generators indoors or in enclosed spaces.

Alternative Heating Options

While electric space heaters are a good idea for short-term power outages, you may want to explore other heating options for longer durations.

Propane heaters or gas heaters can be more efficient in terms of fuel consumption. However, they come with their own safety considerations, such as proper ventilation.

Solar Power 

If you’re environmentally conscious and want a more sustainable option, you can also look into solar generators powered by solar panels. They can provide you with clean, renewable energy during emergencies.


In conclusion, the right size generator for your space heater depends on the wattage of your heater and the total wattage of all devices you want to power.

Always prioritize safety, and consider alternative heating options for extended outages.

Whether you opt for a small portable generator or invest in a whole-house standby generator, make sure it meets your power requirements. Stay warm and safe during those chilly power outages!

Before you go, here are more posts to enjoy:

11 Best Generators Made in USA

What to Pack in Car Emergency Kit

Organic Freeze Dried Emergency Food

What Size Generator to Run a Space Heater