When comparing home appliances and electrical devices in general, you may have noticed that many of them have two power consumption values: running watts and starting watts.
- Starting wattage:As you might guess, this is the electric power needed to start a device. The starting watts are also known as surge watts.
- Running wattage:This is the power you need to keep an electrical device running, once it has been switched on. Depending on the device, the running wattage can be lower than the starting wattage or equivalent.
Understanding the difference between running watts and starting watts is very important when choosing a backup power system. A portable generator must be capable of providing both the running watts and the starting watts of all the equipment you want to power.
Running Watts vs Starting Watts: Understanding the Difference
Some electrical devices need additional power to get started. For example, when you switch on a pump motor, it must overcome inertia and friction while picking up speed. The pump must also overcome the pressure in the piping system before water can start flowing. Since the pump motor works harder initially, it needs additional watts.
- In this case, the starting wattagetells you the power required by the pump motor when overcoming the initial resistance.
- The running wattagetells you the power consumption once the pump has started and water is flowing normally.
Generally, the starting watts required by pumps and other motor-driven devices are higher than their running watts. For example, you may find a sump pump with a starting wattage of 2,000W and a running wattage of 1,000W. The list of devices with electrical motors also includes air conditioners, heat pumps, fans, refrigerators, washing machines and clothes dryers.
There are also electrical devices that don’t require additional watts when starting. For example, LED light bulbs and electronic gadgets can be switched on without an extra power input, which means their starting watts and running watts are equivalent.
What Do Starting Watts Mean on a Generator?
Generator specifications also include a starting wattage and running wattage. In this case, the values describe the power output that the generator can provide. For example, a generator with a starting wattage of 4,000W and a running wattage of 2,000W can power a combination of devices that will not exceed these two values.
- Ignoring the starting watts of electrical devices is one of the most common mistakes when choosing a portable power station.
- If you want to use a device that requires 3,000 starting watts and 1,500 running watts, there is no problem. Both values are below the generator’s capacity.
- However, you cannot use a device that requires 4,500 starting watts and 1,500 running watts. Even if the generator can provide the running watts, it cannot start the device.
The starting wattage of home appliances is not a problem when using electricity from the grid, since you can draw additional power at any time. However, the starting wattage becomes critical when using a solar generator off-grid or during a blackout. Before connecting any devices to the portable generator, you must make sure their starting wattages will not exceed its capacity.
Where to Find the Starting Wattage and Running Wattage of Home Appliances?
Normally, you can find the starting power and running power of home appliances on their nameplates or instruction manuals. If the nameplate of an electrical device is out of sight or difficult to reach, you can find the specifications online by visiting the manufacturer’s website.
Some electrical devices have a single wattage value, which is not labeled as running watts or starting watts. When this happens, it normally means that the both values are equal. For example, you may find an LED light bulb with a rated power consumption of 9W. In this case, the starting wattage and running wattage are both 9W.
The following table provides some typical starting wattages and running wattages for home appliances. Keep in mind that the actual wattage of your devices may vary depending on their brand and product model.
|
Electrical Device |
Typical Running Watts |
Typical Starting Watts |
|
Table Fan |
30W |
70W |
|
Ceiling Fan |
70W |
150W |
|
LED Light Bulbs |
90W (9W each) |
90W |
|
Coffeemaker |
1,000W |
1,000W |
|
Laptop computer |
60W |
60W |
|
TV |
100W |
100W |
|
Air Conditioner |
1,200W |
2,400W |
|
Resistance Heater |
1,500W |
1,500W |
|
Sump Pump |
1,000W |
2,000W |
|
Microwave |
1,000W |
1,000W |
|
Toaster |
1,100W |
1,100W |
|
Washing Machine |
800W |
1,800W |
To size a generator, you must consider all the running wattage and the starting wattage that causes the largest increase in power.
- For example, if you add all the running wattages in the table above, you get 7,950W.
- The device with the highest starting wattage is the air conditioner. It uses 2,400W when starting, which represents an extra 1,200W beyond its running wattage.
- In this case, you would need a total generator output of 9,150W.
To size a backup power system optimally, you only need to consider the device with the highest running wattage. If the generator can start this device, it will also be able to power all other devices with lower starting wattages.
Starting Watts and Running Watts for a Solar Generator
When you purchase a portable solar generator, the running wattage and starting wattage are often labeled as rated power and surge power:
- Rated power (running watts):This is the power output that the solar generator can deliver continuously, to provide the running watts needed by electrical devices. Rated power is also known as continuous power.
- Surge power (starting watts):This is a higher power output that the generator can provide for short periods of time, also known as peak power. The surge power is used for devices with a starting wattage above the normal output of the generator.
Most portable solar batteries are designed for appliances with combined running power of less than 2,000W. This allows the use of a lighter and more compact battery, with a small array of photovoltaic panels. Portable power stations are not normally used for high-power devices such as central air conditioners, since they would require a much larger battery and solar array.
If you plan to use a portable solar generator, you can achieve better results with energy efficient appliances. You can look for devices with the ENERGY STAR label, which indicates that a product has been tested for efficiency according to US federal standards. Energy efficient appliances have a lower electricity consumption, which means you can power more appliances with a single solar battery.
