The Bright Ideas Blog

Design inspiration and outdoor lighting tips and advice for homeowners

Can I Add More Lights to My Existing Landscape Lighting System?

It is absolutely possible to add additional fixtures to your existing system, but there are a number of factors that first need to be considered.

What size is your transformer? 

Transformer size dictates how much load can be placed on the system. Simply put, a larger transformer can handle more lights then a smaller one.

But how does this work exactly? Let’s use a 150 watt transformer as an example. A typical halogen lamp is going to need 20 watts of power. A 150 watt transformer can only support up to 150 watts of lamps. This means the most you could add onto this transformer would be 140 watts, or 7 halogen lamps.


However, putting 140 watts of power onto a 150 watt transformer is really pushing it to its limits. The largest load a transformer should have placed on it should be 80% of its maximum capacity. 80% of a 150 watt transformer maximum capacity would be 120 Watts of power. This means that on a 150 watt transformer only 6, 20 watt lamps, would be able to fit comfortably on a transformer of this size.

Why only 80%? It’s never a good idea to push a transformer too hard. For example, if you run a 150 watt transformer too close to 150 watts, it will continually trip and have to constantly be reset. In addition, running it too high will leave the transformer running hotter and potentially over work it. If your transformer is nearing maximum capacity you can upgrade to a larger transformer.  

The solution to adding more lights isn’t always to upgrade to a larger transformer, however.

Even if you have a smaller transformer, if only half its capacity is currently being utilized, you can add more lights.

If your transformer has reached its max capacity (approximately 80% of its wattage) then you can either replace it with a larger transformer to make more room or add an additional transformer.

The advantage of adding an additional transformer is that it allows you to break your lighting system up into different zones. You could have one transformer control the backyard while the other controls the front.

Is your current system Halogen or LED?

It’s important to consider whether your system is halogen or LED. If you have a halogen system, that’s great news. By retrofitting your halogen lighting system to LED, you’ll be able to open up room on your transformer for additional LED lamps to be added.


When you retrofit a halogen system to LED, the size of the transformer becomes less of an issue because you are stepping down the load being placed on the transformer with each LED retrofit fixture.

If a typical halogen MR16 lamp takes up 20 watts, a typical LED MR16 lamp only takes up 4 watts of power. There are some LED lamps that only take up 1.5 watts of power.

If you have a maxed out halogen system and you retrofit the existing fixtures with LED lamps, you will then be able to add nearly 3X the number of lights your transformer could previously support.

 More lights can always be added to your landscape lighting system. There are a couple of instances where you might have to make some changes to your system in order to facilitate more lights.

If you have an LED system with a fully maxed transformer, you won’t be able to add any more lights to that transformer. This is a situation where the transformer will need to be upgraded to a larger size, or an additional transformer will need to be added. It all just depends on your individual situation.



Have questions? 

If you have questions about where to add new lights or whether or not you can add more lights, consult with your lighting designer. With years of experience in the outdoor lighting industry, they can help you refine your ideas for additional lights, as well as weigh in on how best to make it happen.

To learn more about how to add more lights to improve your outdoor living space, call us at (801)440-7647 to schedule a free consultation, or feel free to simply fill out a contact form.

Located in Midvale, Landscape Lighting Pro of Utah serves throughout Utah's residential areas, including Salt Lake City, Park City, Draper, Davis & Utah Counties. Our outdoor lighting portfolio includes projects throughout Utah and beyond.

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