Watts de démarrage vs watts en continu : comprendre la différence

Starting Watts vs. Running Watts: Understanding the Difference

Starting Watts vs. Running Watts: Understanding the Difference

When choosing a generator, a common mistake is to rely solely on the highest number displayed on the box. However, understanding the difference between starting watts and running watts is essential to avoid breakdowns, overloads, and premature wear of the generator.

This guide clearly explains what these two concepts mean, how to use them correctly, and how to avoid the most common mistakes.

What are running watts?

Running watts represent the power that a generator can provide consistently for several hours without straining.

👉 This is the most important figure when choosing a generator.

Examples of appliances that use running watts:

  • Lighting

  • Television

  • Computer

  • Internet router

  • Low-power electric heater

The sum of all appliances connected at the same time must never exceed the generator's running watts.

What are starting watts?

Starting watts (or peak watts) correspond to additional power provided for a few seconds, necessary to start certain motor-driven appliances.

Affected appliances:

  • Refrigerator

  • Freezer

  • Water pump or sump pump

  • Compressor

  • Furnace (blower)

These appliances can require 2 to 3 times more power at startup than when they are running normally.

Concrete example (most illustrative)

Let's take a generator displaying:

  • 3500 running watts

  • 4500 starting watts

👉 This means that:

  • You can power up to 3500 watts continuously

  • You have a temporary margin of 4500 watts to start a motor-driven appliance

⚠️ If the sum of connected appliances exceeds 3500 running watts, the generator will:

  • strain

  • trip

  • or shut down completely

Common mistake to avoid

Connecting several motor-driven appliances at the same time.

Example:

  • Refrigerator

  • Freezer

  • Water pump

Even if the generator has high starting watts, simultaneous peaks can exceed its capacity, causing:

  • voltage drop

  • generator shutdown

  • long-term damage

How to properly use starting watts

Best practices:

  • Start appliances one at a time

  • Prioritize essential appliances

  • Avoid unnecessarily overloading the generator

  • Allow a safety margin when choosing power

Which power to choose according to your needs?

For an overview of how to choose the right power for your home, consult this article:
👉 What size generator to choose for a house

Generator models suitable for these uses

👉 Add Shopify product links for each model.

Conclusion

Always choose a generator based on running watts, while considering starting peaks.
A good understanding of this difference helps avoid costly mistakes and ensures reliable operation during outages.

Also read

Come visit us in-store

S.O.S Surplus d’Outils Spécialistes
4630, boul. Industriel, Sherbrooke (QC)

Do you have questions or want to make a reservation?
📞 Call us at (819) 563-2036

Back to blog