What Size Electric Generator Do I Need for My House

With ageing power grids stretched thin and extreme weather events on the rise, generators have become more of a necessity than a luxury for many American households. A generator helps ensure that critical systems, like heating, cooling, refrigeration, and medical equipment, continue to function even during prolonged power interruptions.

Often, we get questions from homeowners asking “What size electric generator do I need for my house?” and that is what we’re going to answer in this article. For essential appliances to run smoothly, you must have the right size electric generator. Selecting an appropriately sized generator also helps you avoid damaging sensitive electronics and overloading the system itself.

We will walk you through the requirements for a standby generator. We will show you how to calculate what size generator you need to power your house, understand why it’s important to pick the right one, and some important things you need to know about the power needs of your appliances.

What Size Electric Generator Do I Need?

When you’re considering a generator to power your entire house, size does matter. Choosing the correct generator size ensures that you will have enough power to keep the essential appliances and systems running during an outage without the risk of overload or unnecessary strain.

Now the question to answer is, what does “right size” mean, and how can you determine it?

How do I calculate what generator size I need?

Here’s a step-by-step guide on what size generator to power house that is needed to power a 2,000 sq. ft. home (Note that you can apply this simple formula for any size home, we only used 2,000 sq. ft. as an example since it is the median house size in the country).

Step 1: List down all the appliances and systems that are essential in your home. Most households will need electricity for basic systems such as lighting, heating, air conditioning, refrigerators, and also for charging electronics. You can also consider including your well pump or sump pump if you use any, and your stove if you rely on electricity for cooking.

Step 2: Find the starting and running wattage for each appliance.  

What size standby generator do I need? When choosing a generator, it's essential to consider both the starting (surge) watts and running watts of your appliances. Many appliances, such as refrigerators and air conditioning units, require a higher power surge to start their motors before settling into a lower continuous wattage. Be sure to calculate the total starting and running wattage of all appliances you plan to power simultaneously to determine the appropriate generator size.

Step 3: Compute the total wattage.

Calculate and add the surge wattage of the appliances that require the most power to start running. For a 2,000 sq. ft. home, that has basic appliances, it might look like this:

• Centralized air conditioner: 3,500W starting, 2,000W running
• Refrigerator: 1,200W starting, 400W running
• Microwave: 1,200W
• Lighting: 200-300W
• Sump Pump: 1,500W starting, 800W running

With the appliances listed above, you can determine that you need about 6,000 starting watts and a total of 4,500 running watts.

Step 4: Add a buffer for efficiency.

Electric generators run best at around 80%-90% of their rated capacity. To ensure that your backup power supply operates smoothly, make sure to add a buffer or around 20% on your overall running wattage.

Step 5: Calculate the right generator size that you need.

Here is a simple formula to determine the size of the generator that you need:

Generator Size (Watts) = Total Running Watts + (Highest Starting Watts x 20%)

Using our example above, your computation will look like this:

Generator Size = 4,500W + (3,500W x 20%)

                         = 4,500W + 4,200W

Generator Size = 8,700W

This computation tells us that a generator of around 9,000W is recommended to power a typical 2,000 sq. ft. home comfortably. 

How Much Power Do Appliances Require to Start?

What size generator to power house? Determining the right generator size for your home involves understanding the wattage requirements of your appliances. As mentioned, knowing the starting (surge) watts and running watts is critical. To help, here’s a list of the power requirements for commonly used household appliances, which can guide you in choosing a generator that matches your home's needs.

Why is it Critical to Have the Appropriate Size Generator?

Having the right size electric generator is not only a matter of efficiency; it also ensures the safety and longevity of both your power backup system and household appliances.

A generator that is too small for your power requirements can easily become overloaded, which can lead to overheating, and shutdowns and could seriously damage your appliances and systems.

Depending on how the generator is used, a generator that has a capability over your power demand can be both beneficial and problematic.

An oversized generator, naturally, would give you increased power capacity. Huge generators can easily handle surges and starting power demands of large appliances. Also, if you’re planning to expand your home and add more appliances, an oversized generator ensures that you’re prepared for these changes.

What size electric generator do I need? While selecting a generator, it's important to balance your power needs with the generator's capacity. Oversized generators can have drawbacks, including higher initial costs, which might be unnecessary for moderate power requirements. Additionally, fuel-run generators operating at very low loads may consume more fuel than needed, increasing operating costs. They can also face maintenance issues like wet stacking, where carbon, fuel, and moisture build up in the exhaust system, reducing the efficiency of your backup power system. Choosing the right size ensures both cost-efficiency and reliability.

When you're deciding what size generator you need, the rule to remember is that you have to balance your current energy needs with your potential future demands. Although an oversized generator can offer you flexibility and peace of mind, it can lead to higher costs and inefficiency if not properly managed. By calculating your home’s power requirements using our tips above, you can choose the perfect generator size to keep your household running smoothly, even during power outages.

Solar Generators to Power Your Whole Home

While conventional fuel-powered generators can meet high wattage demands, solar generators are emerging as a more popular option due to their convenience and eco-friendly operation. Whole-house generators, such as Nature’s Generator Powerhouse are built to sufficiently supply power to your essential systems and appliances. They are an excellent option for homes that want to be energy-efficient and reduce their carbon footprint.

In terms of future use, Nature’s Generators were designed with expandability in mind. This means you have the ability to scale up your backup power system as your energy needs grow–whether by adding more solar batteries for greater storage capacity, adding solar panels or connecting wind turbines to harness more renewable energy.

If you have more questions or require help what size generator to power your house, please don’t hesitate to contact our support team.

Conclusion

Choosing the right generator size is crucial for ensuring reliable power during outages without overspending or dealing with inefficiencies. By understanding your home's power needs, including running and starting wattages, you can select a generator that matches your requirements perfectly. Whether you opt for a portable, inverter, or standby generator, sizing it correctly ensures optimal performance, lower fuel consumption, and a longer lifespan for your backup power system. Taking the time to evaluate your current and future power demands will help you answer the key question: What size electric generator do I need? With the right choice, you’ll have peace of mind and a dependable power source when you need it most.

* We want to give credit where credit is due. Professional writer, Ishna Sablaya, contributed research and content to this blog titled: What Size Electric Generator Do I Need for My House Thank you, Ishna, for your contributions!