ATS vs Interlock Kit: Backup Power Comparison

Introduction

When the power goes out, having a reliable backup power solution is crucial. Two popular options for connecting a portable generator to your home are automatic transfer switches (ATS) and interlock kits. Both allow you to power your home during an outage, but they differ significantly in convenience, cost, and installation complexity. In this article, we compare ATS vs interlock kits to help you decide which backup power option wins for your needs.

What is an Automatic Transfer Switch (ATS)?

An automatic transfer switch is a device that automatically detects a power outage and switches your home's electrical supply from the utility grid to your backup generator. When the grid power returns, the ATS switches back to utility power and shuts down the generator. This seamless transition means you don't have to manually plug in or start the generator—it's all automated.

Key Features of an ATS

• Automatic operation: No manual intervention required.
• Whole-house or essential circuit coverage: Can be sized to power your entire home or just critical circuits.
• Professional installation: Requires a licensed electrician and often a permit.
• Higher cost: Equipment and installation are more expensive.
• Generator compatibility: Works best with standby generators, but can be used with portable generators that have auto-start capability.

What is an Interlock Kit?

An interlock kit is a mechanical device that prevents your main breaker and generator breaker from being turned on at the same time. It ensures that you cannot backfeed utility lines, which is a safety hazard for linemen. With an interlock kit, you manually switch breakers to direct power from your portable generator to your home's electrical panel. You control which circuits get power by turning them on or off.

Key Features of an Interlock Kit

• Manual operation: You must be home to start the generator and flip breakers.
• Selective circuit powering: You choose which circuits to power by managing breakers.
• Lower cost: Kits are inexpensive, and installation is simpler.
• DIY-friendly: Some homeowners can install with basic electrical knowledge, but professional installation is recommended.
• Compatibility: Works with any portable generator that has a compatible outlet (e.g., 30-amp or 50-amp).

Comparison Table: ATS vs Interlock Kit

Pros and Cons

Automatic Transfer Switch (ATS)

Pros:

• Fully automatic—ideal for unattended operation.
• Can power entire home if generator is large enough.
• Seamless transition during outages.
• Increases home value.

Cons:

• Expensive to purchase and install.
• Requires professional installation and permits.
• Overkill for rare outages.

Interlock Kit

Pros:

• Affordable and cost-effective.
• Simple installation for experienced DIYers.
• Flexible—works with any portable generator.
• Allows you to prioritize circuits based on generator capacity.

Cons:

• Manual operation—you must be home and physically switch breakers.
• Not suitable for unattended backup.
• Limited to circuits you manually manage.
• Requires careful load management to avoid overloading generator.

Which Backup Power Option Wins?

The winner depends on your specific situation:

• Choose an ATS if: You want fully automatic backup power, experience frequent or lengthy outages, have a large home or critical medical equipment, and are willing to invest in professional installation and a standby generator.
• Choose an interlock kit if: You're on a budget, have occasional outages, already own a portable generator, are comfortable with manual operation, and want a simple, reliable solution.

For most homeowners who already have a portable generator and face infrequent outages, an interlock kit offers an excellent balance of cost and functionality. However, if convenience and whole-house coverage are top priorities, an ATS is the superior choice.

Conclusion

Both ATS and interlock kits provide safe and effective backup power, but they cater to different needs. Evaluate your budget, outage frequency, and willingness to manage manual switches. Whichever you choose, ensure it's installed correctly to keep your home and utility workers safe. With the right setup, you'll be prepared for the next power outage.