Published on November 24th, 2014 | by Peter Young


A Quick Guide To Ballasts: Electric vs. Magnetic


When it comes to making your home more energy efficient one of the places you’re not likely to look is at your ballasts. While it might be a bit obscure, it’s still a valid way of reducing your homes energy consumption. To help you get a better understanding of what a ballast actually is and how it works in your home, we’ve put together the following guide:

A quick guide to ballasts:

How they work – The job of a ballast is to limit and reduce the amount of electricity traveling through a given electrical circuit. Much like a restricter plate that limits the top speed of vehicle, the ballast puts a cap to how much energy can travel through a circuit. Why? Because if left un-regulated, the level of electricity traveling through a circuit could exceed the limit of the light bulb, which will result in the bulb burning out, or in some cases, actually exploding the bulb. Yikes! To get a better idea of how an electrical ballast works (and a more technical definition) check out the video below:

Where you’ll find them and the different types – Ballasts will be found anywhere in your home that you have fluorescent tube lighting. However, the type of ballast you find there may vary from fixture to fixture, here are the two most common types of ballasts you may encounter:

  • Magnetic Ballasts – This style of ballast uses a single induction coil (typically a copper wire) in order to reduce the amount of charge in a given electrical circuit.
  • Electronic Ballasts – This style will use a series of of inductions coils (versus the single coil of a magnetic ballast) and also regulates the amount of charge in a given electrical circuit.

Magnetic vs. Electric: Which is better?

When you compare these two styles of ballasts, the electric style is better on most accounts. It’s smaller in size, lighter in weight, more efficient at inducting current (by roughly 20%!), doesn’t make any noise, prevents your lights from flickering and it will save you money. Plus, you can use an electric ballast to control the power to multiple lightbulbs within a fixture (unlike magnetic ballasts which can only control a single lightbulb). However, magnetic ballasts do have one very notable advantage: in very cold climates (where the ballast is going to be outside), magnetic ballasts will outlast electric by almost 10:1 in their lifespan.

So how can you tell which type of ballast you have? Turn on your light and see if you can identify either of these symptoms:

  • Buzzing from the lamp
  • Flickering of the light

If you pick up on either one, than odds are you have a magnetic ballast. However, that’s not the only way to tell which type of ballast you have. Simply take your cell phone (or digital camera) and take a picture of your lights while they’re turned on. Now, look at your picture. Do you see any dark bands or stripes, sort of like a checker board? If so, you have a magnetic ballast. However, if your picture is clear, than the ballast is electric. This is because electric ballasts operate at a much higher frequency (20,000 hertz vs. 60 hertz for magnetic).

Check out this photo from Envision Lighting to see how this looks.

Screen Shot 2015-08-20 at 11.13.39 AM

Can I swap out my ballasts myself?

In short, yes. It is not rocket science, but you may also consider just finding plug-n-play LED T8’s instead of going through all the hassle. They cost more than regular bulbs, but they’re more flexible (they work in both magnetic and electric ballasts) and they’re much more energy efficient (using about 50% less electricity).

Modern electrical ballasts can replace just about any magnetic ballast so long as you know what you’re doing. Installing them isn’t overly complicated, and if you fancy yourself a handy-person you should be able to tackle the project yourself. Check out this video to get an idea for what that process looks like. Just keep in mind that every brand and every ballast may be slightly different in its wiring scheme and installation instructions, so always refer to the instructions on the package itself, rather than a video like this one. This video is just for example:

Simple, yeah? If you’re at all unsure about the process of installing a new ballast, we recommend that you contact a professional to assist you.


Photo courtesy of Flickr Creative Commons (Ballast)

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  • Harold Sogard

    Super helpful. Thanks for posting this!

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