How to Choose the Right Generator Size for Your Needs (2024)


Power outages can happen at any time and without warning. Whether it's a severe weather event, a local power grid issue, or another unforeseen circumstance, finding yourself without power can be much more than an inconvenience - it can disrupt life as you know it. That's why having a backup generator is a critical piece of household preparedness. But not all generators are created equal. It's important to select the right size generator to meet your unique power needs during these emergencies. This blog post provides comprehensive guidelines on how to determine what size generator you need based on the appliances and devices you want to power, as well as other considerations such as fuel type, noise levels, budget, and maintenance. Be power ready, read on to find out how you can best equip your home for a power outage!

Assessing Your Power Needs

In the event of an energy outage, it's crucial to prioritize the appliances and tools that are absolutely indispensable to your daily activities. To do this, you need to create a list of the essential appliances and devices you would want to power during such situations.

Refrigerator and Freezer

Your fridge and freezer are vital in preserving perishable foods and medication. In a power outage, their functionality can be the difference between having accessible and safe food or not.


Providing proper illumination is essential, especially during natural disasters where power outages frequently occur at night. Without lighting, your safety and security may be compromised.

Heating or Cooling Systems

Depending on your geographical location, heating systems can prevent pipes from freezing in winter while cooling systems can make extreme summer temperatures bearable. Continuous operation of these systems can be essential.

Medical Equipment

For those who rely on powered medical equipment, this should be at the top of your list. Power outages can be life-threatening to individuals dependent on devices such as ventilators, oxygen concentrators, and home dialysis equipment.

Communication devices

During an emergency, maintaining communication with the outside world is crucial. This includes devices like mobile phones, radios for receiving updates, computers for obtaining crucial information, or rechargeable batteries for these devices.

By thoroughly assessing your power needs, you ensure the safety and well-being of your household during a power outage. This evaluation not only prepares you for a more manageable disaster experience, but also allows you to efficiently allocate power resources.

Understanding Generator Sizing

Choosing the right generator size is critical for powering your appliances or running your equipment smoothly. An essential aspect of generator sizing involves understanding the comparison between starting watts and running watts, and figuring out the total wattage that all your appliances will consume.

Starting Watts Vs. Running Watts

The concept of starting watts and running watts pertains to two different power requirements for appliances. The starting watts, also known as 'peak watts', are the extra power that your devices will need to start-up. On the other hand, running watts, also termed as 'rated watts', refer to the continuous amount of power an appliance requires to function after it has started.

For instance, consider a typical fridge. When you plug it in initially, an influx of electricity is required to start its mechanisms, such as the compressor. After a short spike in energy, the fridge will then settle into a steady, lower operational level, which is sustained over time.

This power spike is why some appliances, such as refrigerators, air conditioners, power tools, and pumps, list both starting (or 'surge') watts and running (or 'continuous') watts in their specifications. The starting watts are typically higher than the running watts. It is crucial to consider both when choosing a generator.

Calculating Total Wattage for All Appliances

Determining the total wattage needed for all appliances is a key step in ensuring the selected generator can sufficiently support the power load. To do so effectively, you need to take inventory of all the appliances you intend to run with the generator.

Start by listing each item and determining their individual starting and running watts. You can often find this information in the product specifications or the owner's manual. For instances where this data is not available, several online resources provide estimates for common household appliances.

Once the power requirements for each appliance are known, add up the starting watts of all the devices you plan to start simultaneously and calculate the total running watts for all items you plan to run at the same time. The total starting watts dictate the minimum starting capability your generator should have. Similarly, the total running watts give you the minimum continuous power capability needed.

Remember, it is always wise to choose a generator that can produce more power than your total calculated requirement. This buffer will cater to any unforeseen spikes in power demand or any errors in your initial calculations. After all, it is better to have more power than you initially thought you’d need rather than less.

The process of understanding generator sizing might seem complex at first glance but becomes relatively straightforward with a good grasp of these fundamentals. Investing some time to run through these steps can save you a lot of hassle down the line and ensure you select the most suitable generator for your needs.

Choosing the Right Generator Size

Generators come in various sizes, each designed to meet a specific range of power needs. Therefore, understanding these sizes and their capacities is crucial for choosing the right generator for your home. The three primary categories of generators are:

  • Small portable generators
  • Mid-size home standby generators
  • Large, whole-house generators

Small Portable Generators

Small portable generators usually have power ratings ranging from 1,000 to 5,000 watts. Their portability makes them convenient for outdoor activities such as camping, picnics, and backyard parties. They can also serve as emergency backup power for small appliances like fridges and TVs. However, they may be inadequate if you need to power large appliances or your entire home.

Mid-Size Home Standby Generators

Mid-size home standby generators, with power ratings of approximately 5,000 to 10,000 watts, represent a moderate power option. They are preferable when you need to power more than just small appliances, such as running essential household systems like heating and cooling. However, they are stationary and require permanent installation.

Large, Whole-House Generators

Large, whole-house generators are the most powerful option, with ratings over 10,000 watts. These generators can efficiently power all appliances and systems in your house, making them a solid choice for expansive residences or areas prone to lengthy blackouts. Note that they are also stationary, require professional installation, and tend to have a higher upfront cost.

Matching Wattage with Generator Size

Knowing how much total wattage you need is critical in determining the size of the generator required for your needs. For example, a standard refrigerator requires about 600 watts to run, while a central air conditioner may need up to 4,000 watts.

While smaller generators are commonly used for powering select appliances, mid-size generators offer a balance of power and flexibility, suitable for powering essential household systems without going overboard. For those who require a cover-all solution, large whole-house generators deliver the necessary wattage to keep everything in your house functioning during an outage.

In summary, the right generator size depends on your power needs. Smaller portable generators are more affordable and convenient for outdoor use or powering a few appliances. Mid-size generators offer more power capacity, suitable for comprehensive household needs. Large, whole-house generators provide the most power, ensuring your home operates normally even during prolonged blackouts. However, they come with a higher purchase and installation cost.

Making an informed decision about the right generator size will ensure you have sufficient, reliable power when you need it.

Additional Considerations

When deciding on the perfect generator to meet your needs, several factors come into play. One must think about fuel type and availability, the noise generated by the machine, and the overall cost, both initial and maintenance. This article will explore each of these elements in detail to help you make an informed decision.

Fuel Type and Availability

One of the first things to consider when buying a generator is the type of fuel it uses. The most common types are gasoline, propane, and diesel.

Gasoline Generators

Gasoline generators are popular due to the widespread availability of gasoline. However, they do have a few downsides. Firstly, gasoline has a short shelf life and can degrade over time, leading to potential damage to the generator's inner working components. Secondly, gasoline is also highly flammable, creating a safety risk, particularly in an enclosed space.

Propane Generators

Propane generators, on the other hand, are known for their long shelf-life. Propane can be stored safely for long periods, making it ideal for infrequent power outage situations. The major downside to this type of generator is the required storage space for large propane tanks.

Diesel Generators

Lastly, diesel generators are renowned for their efficiency and longevity. Diesel burns more slowly, therefore these generators usually last longer and require less maintenance. However, just like gasoline, diesel fuel can degrade over time and the fuel is also more expensive.

Noise Levels

The noise level of a generator is a major factor to consider, especially if you live in a residential area. Noisy generators can cause disturbance and discomfort, potentially running afoul of local noise regulations. Many modern generators come with sound attenuating enclosures and other noise-reduction features. As a general rule of thumb, the smaller the generator, the lower the noise output.

Budget and Maintenance

Cost is undoubtedly a leading factor when deciding on a generator. The initial purchase may be a hefty investment, particularly for larger, more powerful units. However, remember to also consider the ongoing maintenance costs. While some generators may be cheaper upfront, their long-term maintenance could end up costing more.

Maintenance needs vary by generator size and type. For example, diesel generators often require less maintenance but the fuel is more costly. Conversely, gasoline and propane generators may require more frequent maintenance, but their fuelling costs can be less.

In conclusion, the choice of a generator depends on numerous factors. While initial cost and noise level are important considerations, it is also essential to think about ongoing maintenance expenses, fuel availability, and safety risks. Understanding these elements will help you select a generator that best serves your needs. It's all about striking the right balance between these different aspects to ensure your investment provides sustainable and reliable power when you need it most.


In this article, we have thoroughly discussed the essential aspects to consider while determining the appropriate generator size for your needs. It's necessary for every household to design a comprehensive plan for emergency power outage scenarios. The last thing anyone wants is to face a power outage only to find out that their generator is not capable of supporting their appliances and devices.

One of the critical points we have examined is the crucial need to assess your power requirements accurately. It's vital to make a list of all the electrical appliances and devices you'd need to power during an outage. This list will help you calculate the total power consumption conveniently. Remember, you should also factor in both running watts and starting watts of your appliances.

We've also underscored the significance of considering the generator's fuel source and the generator's fuel efficiency. These elements directly impact the operational cost and the environmental footprint of your generator. Would you prefer a gas, diesel, propane, or solar-powered generator? Your decision can significantly influence your budgeting, installation, and maintenance processes.

Pertinently, we've highlighted the importance of safety features in your chosen generator. Features like automatic low-oil shutdown, overload protection, and cover against rain and snow are not just add-ons; they are necessities to ensure the long lifespan of your generator and the safety of your family.

Lastly, we've emphasized the need to consider the generator's physical size. Depending on your space availability and local regulations, choose a generator that will fit seamlessly into your space without breaking any rules or causing inconvenience.

Before making that crucial investment in a generator, it's beneficial to do diligent research, perhaps with the assistance of a professional, to understand better the ins and outs of this indispensable asset. Your decision should ultimately align with your power needs, budget, space availability, and personal preferences.

Purchasing a generator doesn't need to be a daunting task. A suitable generator can bring peace of mind knowing that you're prepared for power outages and emergency situations. The information provided in this article should guide you in making a well-informed and confident decision. Bear in mind that an adequately sized generator is not only about handling your power requirements—it's about ensuring the comfort, security, and seamless operation of your home during periods of power outage.