Understanding Generator Sizing Factors

What is wattage?

Wattage is a unit of measurement that can measure how many watts a generator produces; it can be calculated by multiplying volts (V) and amps (A). For example, if your home appliance voltage is 220V and the amps is 30A, then the device power is 6600 watts. Generally speaking, a generator’s power range is from 1,000 watts to 500,000 watts.

Starting vs. Running Wattage

Starting (Surge) Wattage: When we start a home appliance, it will need more power than its rated power, often 2-3 times higher than its running wattage.

Running (Rated) Wattage: After our devices start, they will provide continuous power to keep appliances operating.

Factors Affect Your Generator Size

Essential Appliances List

Before choosing a generator, we’d better consider our generator usage scenarios and loading devices. For example, when we plan to buy a generator for home power backup, we should first know how many devices we need to power. So creating a list for all the devices and appliances we need to power during an outage, such as refrigerators, air conditioners, TVs, lights, and so on.

Calculate The Wattage Needs

As we all know, every appliance has a manual or data sheet. We can make a list of them and write down different devices’ running wattages and starting wattages.

Example Wattage Requirements Table:

Add Up Wattages

After we list all the devices wattages, we can first add all the running wattages together. Formula: Total Watts = (Starting Watts of Largest Appliance) + (Sum of Running Watts of Other Devices). Take the wattage table above as an example, The total running wattage is 5,400 watts. Then we can add the total running wattage with the highest starting wattage, 2,200 watts, and then we can figure out 7,600 watts. So, 7,600 watts will be your minimum required generator size.

Types of Generators & Wattage Ranges

Portable Generators

• Small Type: This type of generator is from 1000 watts to 2000 watts.
• Middle Size Type: From 2,000 watts to 3,500 watts, quiet and fuel-efficient for basic home needs.
• Large Type: Up to 8,500W, powerful enough for most home essentials.

Home Standby Generators

• Basic Standby Power: 5,000W, powers lights, fans, sump pump, and refrigerator.
• Small Standby Power: 6,500W, adds television and heating/cooling.
• Middle Size Standby Power: 8,000W, includes home office equipment.
• Emergency Backup: 10,000W-12,000W, covers kitchen and laundry.
• Powerful System: 15,000W, suitable for small homes with additional rooms.
• Mini-Power Plant: 25,000W+, runs mid-sized to large homes comfortably.

Choosing the Right Generator Type

We have shown the different types of generators and their power range. Then, we should know that we should know how to choose the suitable generator for different applications. Please follow up below:

For Home Use

If we want to use a generator at home, due to the different home appliances with different loads, choosing the bigger power generator is our best choice. As we mentioned before, the home standby generators are perfect designed for home use.

• 5,000-watt generator: Enough to power essentials like lights, refrigerator, and freezer.
• 15,000-watt generator: Provides a more comfortable experience with additional appliances like central AC and water heater.
• 25,000-watt generator: Can power most household needs, including laundry rooms and household electronics.

For Camping

If we are planning to go camping, then some appliances are a necessity, such as a small fridge, lights, and so on, and we also should consider the portability. So, portable generators are our best choice.

For Construction Sites

If we need to use a generator on construction sites, we need the stable output power; then the generator should be portable. So, we can choose the inverter generators, which are quiet and stable.

Other Considerations

Fuel Type

As we know, a generator can run on various fuels, including gasoline, diesel, natural gas, and propane. Different fuels have their own features. Or we can call it an advantage or disadvantage, such as cost, efficiency, availability, and storage.

Size and Portability

Whether the generator is portable or not, you also need to consider it. If we use a generator for the home and should load many high-power appliances, the standby power generator is suitable for you. If you don’t need to load many appliances, the portable generator is your best choice: less cost, portable.

Noise Level

If you plan to use your generator in a suburban area or at outdoor events such as camping, and require noise restrictions, I think the quiet inverter generator is suitable for you because it has the features of silence and stable power.

Safety Tips

• Never run a generator in a closed space in case of CO poisoning, such as indoors, garage, or in a carport.
• Keep the generator away from your house at least 20 feet, which can avoid the danger and poisoning gas.
• Install the CO detector indoors to prevent the high CO concentrations.

Conclusion

After we talked about the factors, choosing the right size generator is not a problem for you. Neither wasting money nor choosing a generator with insufficient power, the right fit is the best choice. By following these tips step by step and considering your specific needs, you can select a generator that provides reliable backup power.