The Amp-acity of ACs
2. Calculating Your Power Needs
Alright, let's put on our math hats! To figure out if you can run four AC units on a single-phase system, you need to do some calculations. First, find the Running Load Amps (RLA) of each AC unit. This is the steady-state current it draws when it's running. As I mentioned earlier, it should be printed on a label on the unit itself. Write that number down for each of your AC's.
Next, add up the RLA of all four AC units. This will give you the total current draw just from the ACs. But don't stop there! You also need to consider the starting amps, also known as Locked Rotor Amps (LRA). When an AC unit starts, it draws a significantly higher current for a brief period. If all four ACs try to start at the exact same time, that could overload your system instantly.
A good rule of thumb is to add the LRA of the largest AC unit to the total RLA of all four units. This will give you a worst-case scenario estimate. Now, compare this number to the total amperage available in your electrical panel. You'll find this number on the main breaker, usually located at the top of the panel. If your calculated amperage exceeds the panel's rating, then you've got a problem. And by problem I mean it won't work, and it's unsafe.
Remember, your electrical panel supplies power to everything in your home, not just the ACs. So, you need to subtract the amperage used by your other appliances, lights, and electronics from the total panel rating before you compare it to your AC load. A good electrician can help you determine a load calculation if you are not comfortable doing it yourself. They have the tools and expertise to accurately assess your electrical system's capacity. It's better to be safe than sorry!
