Transfer Switch vs Interlock Kit - Which One Do You Need?

Transfer Switch vs Interlock Kit

Understanding the Safest and Most Practical Option for Kingwood and Nearby Areas

When installing a portable generator setup, the most common question homeowners ask is:

"Should I get a manual transfer switch or an interlock kit?"

Both options are safe when professionally installed, but they work differently, cost differently, and offer different levels of convenience.

This guide explains each option in plain language so you can choose the one that fits your home and budget.

1. What Is an Interlock Kit?

An interlock kit is a mechanical device installed on your main electrical panel. It prevents your generator breaker and your main breaker from being ON at the same time.

How it works:

Your generator powers the entire panel, but you choose which circuits to run.
You manually turn off non-essential circuits to avoid overloading the generator.
A sliding plate or locking mechanism ensures the main breaker cannot energize the panel when the generator is connected.

Pros:

Most affordable option
Lets you use any circuit in your home (selectively)
Clean, simple installation
Minimal extra hardware needed

Cons:

Must match your panel brand/model
Not available for all panels
Requires you to manually choose circuits during an outage

Best for:

Homes where the homeowner is comfortable manually managing their circuits.

2. What Is a Manual Transfer Switch (MTS)?

A manual transfer switch is a separate small panel installed next to your main electrical panel.

How it works:

You choose specific essential circuits (usually 6-10) to put on the switch.
During an outage, you flip the switch to transfer those circuits to generator power

Pros:

Very simple for homeowners to use
Clear labeling for each essential circuit
Great for people who don't want to manage the entire panel
Works with almost all panel brands

Cons:

Higher cost (more materials and wiring)
Only powers the selected circuits
Not as flexible if you want to power something not on the chosen list

Best for:

Homeowners who want a fast, easy-to-use system during outages.

3. Cost Comparison

Interlock Kit:

Installed cost: $1,200-$2,500+

Transfer Switch:

Installed cost: $1,500-$3,500+

4. Safety Comparison

Both options are safe and legal when installed by a licensed electrician.

Interlock Kit Safety:

Mechanical lockout system prevents dangerous backfeeding

Transfer Switch Safety:

Completely isolates selected circuits from the utility grid
Very clear operation for non-technical users

Both meet NEC requirements when installed properly.

5. Which One Is Better for You?

Here’s the simple breakdown:

Choose an Interlock Kit if:

You want the most cost-effective option
You want full panel access (you choose circuits manually)
Your panel is compatible
You don’t mind a little manual work during outages

Choose a Transfer Switch if:

You want the easiest and fastest operation
You prefer a dedicated panel for essential circuits
Your main panel is older or incompatible with interlocks
You want to keep things as simple as possible for family members

Real-World Example (Kingwood Home)

A recent homeowner in Kingwood requested backup power for:

Refrigerator
Deep freezer
A/C
Lights
Internet

Their panel was compatible with an interlock kit, so they saved by choosing the interlock instead of an MTS- while still powering everything they needed.

Real-World Example (Porter Home)

A home in Porter had an older, incompatible panel. They chose a manual transfer switch, which:

Made operation easier
Worked perfectly with their 30-amp generator
Avoided the cost of a panel upgrade

Final Recommendation

Both systems are safe and reliable. The right choice depends on:

Your budget
Your panel type
The circuits you want to power
Whether you prefer simplicity or flexibility

If you’re unsure which one fits your home, a quick assessment is the best way to find out.

Need Help Deciding?

We install both interlock kits and manual transfer switches throughout Kingwood, Porter, New Caney, Atascocita, Humble, Spring, The Woodlands, and Conroe.

Transfer Switch vs Interlock Kit - Which One Do You Need?