If you’ve been through hurricane season in SWFL and experienced a power outage, you’re probably wondering what size generator you need to run your air conditioner. Since it’s pretty common for us to experience severe weather here in SWFL, having an emergency power source like a backup generator is ideal. It’s typically not too bad to go through the storms themselves without power, the real issues come after the storm has passed, but electricity hasn’t been restored. Sometimes it can take days or even weeks.

If you’re thinking about getting a source of backup power, you’ll need to know how much power you need to run your AC and other appliances. There’s no one-size-fits-all answer, but we can help you figure it out. The size of the generator you need depends on the size of your AC unit and how much power it requires to run. In this blog post, we’ll help you figure out which generator size is right for your AC needs. We’ll explain how to calculate your AC unit’s power requirements, plus any other essential appliances, and how to choose the right generator size to have enough power for your home. Read on to learn more!

Types of Generators

When you’re shopping for a generator, you’ll notice there are two types that can run a central air conditioner, standby generators and portable generators. Choosing the best generator for you just comes down to a few factors. Let’s compare the two.

Portable Generators

Portable generators can be moved and easily transported. The benefits and downsides of a portable generator are:

  • Less expensive: This type of generator will cost anywhere from $500 to $2000.
  • Powers your essentials: AC, refrigerator, etc.
  • Manual startup: If the power goes out, you’ll have to go out and manually start a portable generator.
  • No installation or maintenance needed: Portable generators can be stored in your garage and basically forgotten about until you need to use them.
  • Will need to be refueled frequently while running: Portable generators typically run on gas, diesel, or propane.

Standby Generators

A standby generator is wired into your home’s electrical system. It’s installed outside of your home in one location and is considered stationary. Here are some benefits and downsides of standby generators:

  • More Expensive: You’re looking at $3000 to $5000 for a standby generator, plus an additional $2000 to $4000 for installation.
  • Automatic startup: When the power goes out, a standby generator automatically starts running.
  • Powers the entire house: Having a standby generator means everything operates as usual when your power goes out.
  • Requires regular maintenance: This unit must be maintained to ensure it will continue to power your home in emergencies.
  • No fueling required: Over the life of the standby generator, you’ll spend less time on maintenance because you won’t need to maintain it by refueling while it’s running.

Generator Sizes

Home generators are typically sized based on the amount of power needed to meet your home’s needs. The size of the generator refers to its electrical output and the size you need is determined by the wattage of all the appliances and devices that will be powered by the generator. Generators are sized by watts (W) or kilowatts (kW), 1 kW = 1,000 W.

Portable generators can range from 2,000 watts to 10,000 watts, while standby generators can range from 10,000 watts to several hundred thousand watts.

How to Calculate What Size Generator to Run Air Conditioner

Calculating the correct size generator for what you want to power in your home is really important. If you choose a generator with less power than you need, it can overheat and damage your AC or other appliances.

Powering Just Your AC

1. Determine the wattage of the AC unit. This can usually be found on the AC unit‘s nameplate or in its user manual, but you’ll need to do a little calculation. First, you’ll calculate the tonnage of your unit. An AC unit is measured in tons and BTU’s (British Thermal Units). Look for the unit’s model number, which you can find on the manufacturer’s label on the unit itself. Contact the manufacturer with the model number to get the number of BTU’s or find it listed in the unit’s manual. If the unit is measured in BTU’s, you just need to calculate the tonnage from that number. 1 ton = 12,000 BTU’s, so you’ll divide your unit’s number of BTU’s by 12,000 to find out how many tons it is. 

For example, if your unit is 24,000 BTU’s, it would be 2 tons (24,000 ÷ 12,000 = 2).

2. Once you know the AC’s tonnage, you can calculate its wattage. 1 ton = 3,500 watts, so if you have a 2 ton unit, the wattage is 7,000 (2 x 3,500 = 7,000).  

This calculation measures the starting watts of your AC unit, which is the number of watts your AC unit needs to start up (always more than running watts). Based on the calculations, we have determined that for a 2 ton AC unit, you could run a 7.5 kW generator. Remember, this is only to power your AC unit. Not your other appliances. To run additional appliances, you’ll need a larger generator.

Powering Your AC and Essential Appliances

To find the appropriate generator to run more than just your AC, you’ll need to add together the wattage (starting wattage, not running wattage) of each appliance you want to run plus the starting wattage of your AC. Remember that do-it-yourself wattage calculations are only estimates, and it’s a good idea to have a professional give you exact numbers and specific requirements for your home if you’re serious about purchasing a home generator.

Final Thoughts

Getting the right size generator is very important. It’s best to spend more money upfront to get a well-sized generator for your home than to skimp on size to save money and end up having to repair or even replace your AC unit or other appliances because of damage from a generator overheating. Calculating your power needs for a generator to run your AC and other appliances may be confusing, so be sure to contact Dolphin Cooling & Heating for help! We are always happy to assist our community with all of the HVAC needs.