Generator Sizing Explained by a Florida Electrician

If you’re buying a generator for your home or business, one of the first questions is usually: what size generator do you need?

It’s not just about the size of your house or building — it’s about what you want to keep running during an outage. That might include air conditioning, refrigerators, lights, Wi-Fi, medical equipment, well pumps, water heaters, or critical business equipment.

In Florida, storms, heavy rain, and grid issues can cause outages anytime, so choosing the right generator size matters.

What Really Determines Generator Size

One of the biggest mistakes people make is assuming generator sizing is based mostly on square footage. In reality, the most important factors you need to consider are:

1. What you want to power

2. How much wattage those items need

3. Whether any of those systems have startup surges

As electricians, we pay close attention to equipment with motors, like air conditioners, refrigerators, and pumps. These systems often need extra power when they first start up. If your generator is not sized correctly for that startup demand, it may not run everything reliably.

That is why we look at both running watts and starting watts when helping customers choose a backup power system.

Choosing the Right Level of Backup

Most generator setups fall into three simple categories:

• Essential backup power is for covering the basics, such as a refrigerator, a few lights, internet, and limited outlets.
• Partial-home backup provides greater comfort and convenience, often including central air conditioning, kitchen appliances, water heaters, and additional circuits throughout the home.
• Whole-home or whole-building backup is the best choice when you want the property to operate as close to normal as possible during an outage. For businesses, this may include computers, security systems, refrigeration, lighting, and operational equipment.
  

Florida Factors to Consider

In Hillsborough County, air conditioning is often one of the biggest factors in generator sizing. If you want your AC to run during an outage, you will likely need a larger system.

Fuel type also matters. Generators may run on natural gas, propane, or diesel, and each option comes with different installation and long-term operating considerations.

Just as important, your generator needs to be installed properly. Transfer switches, permitting, code compliance, and safe electrical connections all play a major role in building a dependable backup power system.

So, What Size Generator Do You Need?

The honest answer is that it depends on your electrical load and your priorities during an outage. A small portable generator may be enough for a few essentials, while a standby generator may be the better choice if you want dependable backup for your home or business.

The best way to know for sure is to have a professional load calculation done. That allows us to evaluate your power needs, account for startup loads, and recommend a generator that fits your property and budget.

Check out our Portable vs. Standby Generator blog to learn more about which one might work best for your needs.

Choose a Generator with Confidence

Generator sizing does not have to be confusing. With the right guidance, you can choose a system that keeps your home or business protected when the next outage happens.

If you need help choosing the right generator in Hillsborough County, our team is here to help. Click the button below for more information.

When using a generator, always follow proper safety measures, including never backfeeding power into your home and never operating it in an enclosed space.

Related blogs:

Complete Cost Breakdown for a Whole House Standby Generator

Bryan’s Top Pick: The Generator He Recommends Most for Reliable Home Backup Power