What Size Generator Do You Need to Run Your A/C in Western WI and Eastern MN?

When the power goes out in the middle of summer—especially on those 90-degree days with heavy Midwest humidity—staying cool quickly becomes the priority. Homeowners across Western Wisconsin and Eastern Minnesota often wonder whether a generator can keep their air conditioner running.

The answer is yes, but only if it’s the right size. Choosing the right generator to run air conditioner systems safely depends on proper sizing, system type, and startup demands.

A unit that’s too small may struggle to start your system or shut down under load, while an oversized generator can cost more than necessary. Understanding how generator size relates to your air conditioner helps you make a smarter, more affordable choice.

Can a Generator Run an Air Conditioner in Wisconsin or Minnesota?

Yes, a generator can run an air conditioner, but whether it works reliably depends on the type of AC system and the generator’s capacity. Not all air conditioners have the same power needs, and not all generators are built to handle them.

Central Air Conditioners

Many homeowners ask, "Can a generator run a central AC system during an outage?" The answer is yes, but central air conditioners require significantly more power and careful planning to run reliably. They draw a large surge of electricity when they start up, then settle into a lower, steady demand while running. This startup surge is often where undersized generators struggle.

Window or Portable A/C Units

Window and portable units are much easier to power. These systems use significantly less electricity and are often compatible with smaller portable or inverter generators. They’re a common option for homeowners looking for basic backup power for AC in one or two rooms.

Mini-Splits

Ductless mini-split systems fall somewhere in between. They’re usually more energy efficient than central AC and don’t have the same high startup surge, making them more generator-friendly when properly sized.

What Size Generator Do You Need for an A/C in Wisconsin and Minnesota?

When asking what size generator to run my AC, it helps to understand two key terms: starting watts and running watts.

• Starting watts: The short surge of power needed when your AC starts up.
• Running watts: The steady power required to keep your AC running.

Air conditioners always need more power to start than to run, which is why generator sizing isn’t based on a single number.

In general, small window or portable air conditioning units require far fewer watts, making them easier to support with smaller generators. Mini-split systems usually fall into a moderate range, depending on size and efficiency. Central air conditioners typically require significantly higher wattage and may need a larger generator or additional equipment to manage the startup surge.

Because exact requirements vary, professional guidance is the best way to ensure proper sizing.

Types of Generators That Can Run an A/C Unit

Homeowners usually consider one of three generator types.

Portable Generators

Portable generators are a popular entry-level option. They can handle smaller AC units and some household essentials, but may struggle with central air. These generators require manual setup and fueling.

Standby or Whole-Home Generators

Standby generators are permanently installed and automatically turn on during an outage. They’re designed to support higher electrical loads and are often the best solution for homeowners who want reliable backup power for AC and other systems simultaneously.

Inverter Generators

Inverter generators provide cleaner, more stable power and are quieter than traditional portable units. They’re well-suited for window units, mini-splits, and sensitive electronics, but may not be sufficient on their own for larger central AC systems.

Benefits of Using the Right-Sized Generator

Choosing the correct generator size offers more than just cooling during an outage. It also helps with:

• Electrical safety: Reduces the risk of overloads or damage to your air conditioner and generator.
• System efficiency: Helps your generator run smoothly without unnecessary strain.
• Reliable comfort: Keeps indoor temperatures manageable during extreme heat.
• Equipment protection: Prevents premature wear on your generator and your AC system.

Proper sizing ensures your generator does its job without creating new problems.

Choosing the Right Generator for Your Wisconsin or Minnesota Home

Several factors influence generator selection, including the type and size of your air conditioner, whether you want to power additional appliances or systems, and how long or how often power outages occur in your area.

Fuel availability, storage preferences, and local electrical codes also play an important role in determining the right setup.

Why Professional Guidance Matters

Improper generator sizing or installation can lead to safety hazards, code violations, or costly equipment damage. Choosing a generator isn’t as simple as picking one up off the shelf—your air conditioner, electrical panel, and home layout all play a role.

Working with a licensed technician makes certain your generator is correctly matched, installed, and ready to perform when you need it.

Why Homeowners Choose Comfort By Design

Homeowners across Western WI and Eastern MN choose Comfort By Design for trusted guidance on generator recommendations and safe installation. With more than 25 years of experience, our team understands local climate conditions, electrical codes, and how to properly support air conditioning systems during outages.

We focus on solutions that prioritize safety, comfort, and long-term reliability without unnecessary upselling or confusion.

Find the Right Generator for Your A/C

Power outages can be frustrating, and in the heat, they can add extra stress. If you’re unsure what generator makes sense for your air conditioner, Comfort By Design is here to help. We’ll take the time to answer your questions and walk you through options that fit your home, so you’re not guessing when comfort matters most.

Contact us today to speak with a local expert about backup power for AC. We’re here to help you feel prepared and confident when the lights go out.