What Size Generator Do I Need Calculator
Choosing the right size generator is crucial for ensuring that your electrical needs are met without overloading the unit or underutilizing its capabilities. In this article, we will explore how to calculate the appropriate generator size, the factors to consider, and provide a simple generator sizing calculator to help you make an informed decision.
Understanding Generator Sizes
Before diving into the specifics of generator sizing, it’s important to understand what generator size means. Generator size is typically measured in watts (W) or kilowatts (kW). The size of the generator you need depends on the total wattage of the devices you plan to power.
Types of Generators
Generators can broadly be categorized into two types:
1. Portable Generators:
- Typically used for temporary power needs.
- Can power tools, lights, and small appliances.
- Usually have a lower wattage output than standby generators.
- Permanently installed and automatically turn on during power outages.
- Can power an entire home or business.
- Generally have a higher wattage capacity.
- Starting Watts: The wattage required to start an appliance (often higher than running watts).
- Running Watts: The wattage required to keep the appliance running.
- Refrigerator: 200 running watts, 1,200 starting watts
- Microwave: 1,200 running watts, 1,800 starting watts
- TV: 400 running watts, 400 starting watts
- Lighting: 1,000 running watts, 1,000 starting watts
- Refrigerator: 200
- Microwave: 1,200
- TV: 400
- Lighting: 1,000
- Refrigerator: 1,200
- Microwave: 1,800
- TV: 400
- Lighting: 1,000
- Portable Generators: Ideal for temporary use or small jobs. Look for models that provide slightly more wattage than your total calculation.
- Standby Generators: Best for whole-house power during outages. Choose one that can handle your total wattage needs with a margin for future growth.
- Inverter Generators: Great for sensitive electronics as they produce cleaner power. Ensure the inverter generator has a sufficient output rating.
2. Standby Generators:
Factors to Consider When Sizing a Generator
When determining the size of the generator you need, consider the following factors:
1. Total Wattage Requirements
Calculate the total wattage of the appliances and devices you need to power. This includes:
2. Type of Appliances
Different appliances have different power requirements. Here’s a quick list of common appliances and their approximate wattage:
| Appliance | Starting Watts | Running Watts |
|---|---|---|
| Refrigerator | 1,200 | 200 |
| Microwave | 1,800 | 1,200 |
| Air Conditioner (window unit) | 2,200 | 800 |
| Electric Water Heater | 4,500 | 4,500 |
| Furnace Fan | 1,200 | 600 |
| TV | 400 | 400 |
| Laptop | 200 | 200 |
| Lighting (10 bulbs) | 1,000 | 1,000 |
3. Surge Capacity
Surge capacity refers to the extra power required to start an appliance. It’s essential to account for this when sizing your generator. Generally, you should add 20-30% more wattage to your total running wattage to accommodate surge requirements.
4. Total Load Calculation
To find the total load you need to power, sum the running watts of all your devices and add the surge watts for the appliances that require it.
5. Future Needs
Consider any future electrical needs you may have. If you plan to add more devices or appliances, factor those into your calculations.
How to Use a Generator Size Calculator
A generator size calculator can simplify the process of determining the correct generator size. Here’s a simple step-by-step guide to using one:
1. List Your Appliances: Write down all the appliances and devices you plan to power.
2. Find Wattage: Look up the starting and running wattage for each device.
3. Total the Running Watts: Add all the running wattages together.
4. Add Surge Watts: For appliances with higher starting wattage, calculate the additional wattage required.
5. Use the Calculator: Input the total running watts and surge watts into the generator size calculator.
Example Calculation
Suppose you want to power the following appliances:
Step 1: Calculate Total Running Watts
Total Running Watts = 200 + 1,200 + 400 + 1,000 = 2,800 Watts
Step 2: Calculate Total Starting Watts
Total Starting Watts = 1,200 + 1,800 + 400 + 1,000 = 4,400 Watts
Step 3: Add Surge Capacity
To accommodate surge capacity, add about 20%:
Total Watts Needed = 2,800 + (0.20 × 4,400) = 2,800 + 880 = 3,680 Watts
In this example, you would need a generator rated for at least 3,680 watts.
Choosing the Right Generator
Once you have calculated your wattage requirements, you can choose the right generator. Here are some tips:
FAQs About Generator Sizing
1. What happens if I choose a generator that is too small?
Choosing a generator that is too small can lead to overloading, which may cause the generator to fail or damage your appliances.
2. Can I use a generator to power my entire house?
Yes, but you need a standby generator with a sufficient wattage rating to accommodate all your appliances, including high-wattage devices.
3. Is it necessary to account for starting watts?
Yes, it is essential to account for starting watts, as many appliances require more power to start than to run.
4. How often should I run a generator?
It is recommended to run your generator at least once a month to ensure it is functioning correctly and to maintain the battery.
5. Can I connect my generator directly to my home’s electrical system?
Only a qualified electrician should connect a generator to your home’s electrical system using a transfer switch to prevent backfeeding into the grid.
Conclusion
Choosing the right size generator is crucial for meeting your power needs and ensuring the safety of your appliances. By understanding your wattage requirements and using a generator size calculator, you can make an informed decision. Whether you opt for a portable or standby generator, always ensure that it meets your power requirements and has the capacity to handle any future needs. With the right generator, you can enjoy peace of mind knowing you have a reliable power source when you need it most.
