Voltage Explained
Voltage in Permanent Outdoor Lighting: 5V, 12V, 24V, and 48V Explained
Voltage is one of the most important specs in a permanent outdoor lighting system, and it is the spec most likely to be misrepresented in marketing. Here is what each voltage tier actually delivers when the lights go up on your house.
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The Three Things to Know About Voltage
When you compare permanent lighting brands, voltage shows up in almost every spec sheet and marketing pitch. It is also the spec where the most confident-sounding claims tend to be backwards. Here are the three rules that actually hold up in the install.
Higher Voltage = Less Heat
Heat in a wire is determined by current, not voltage. P = V × I. Doubling the voltage halves the current. Halving the current cuts wire heat by 75 percent. This is the same reason the power grid runs at hundreds of thousands of volts.
Brightness Comes From Current
Voltage alone does not make a light brighter. Current does. A higher-voltage system delivers more consistent current across a long run, which is why a 48V roofline stays bright from the first fixture to the last while lower-voltage systems dim along the way.
Engineering Beats Voltage Alone
A poorly engineered 48-volt system can still be worse than a well-engineered 12-volt one. Voltage is one tool. The chip, the driver, the protection circuitry, and the app behind it are what turn a high-voltage spec into a reliable install.
What Is Voltage and Why Does It Matter in Permanent Lighting?
Voltage in a permanent outdoor lighting system controls how far the system can carry power before it needs more help. It affects how much heat builds up in the wire, how consistent the brightness stays across a long run, and how many physical boxes end up mounted on your fascia. It does not, by itself, determine how bright the individual fixture is.
The four voltage tiers you see in this category are 5V, 12V, 24V, and 48V. Each was originally designed for a different use case. 5V chips were designed for indoor electronics and short LED strip runs. 12V is the legacy permanent-lighting voltage. 24V is the current mid-range. 48V is what newer high-end systems run on, and what TruLight uses.
Hear the voltage primer at 1:31 in the videoHow Many Power Injection Boxes Does Each Voltage Need?
This is the single biggest practical difference between voltage tiers. Each power injection is another box on your fascia, another set of wires routed through your soffit, and another connection that can fail. Lower-voltage systems need a lot more of them.
5-Volt Systems
Power injection every 5 to 10 lights. Built for indoor strip lighting and small DIY projects, not residential rooflines.
12-Volt Systems
Power injection every 20 to 40 lights. Common in older permanent lighting installs and budget brands.
24-Volt Systems
Power injection every 50 to 100 lights. The mid-range. Several modern brands operate here.
48-Volt Systems (TruLight)
Power injection every 400 or more lights. 90 percent of our installs use one injection box or less, because most homes are under 300 linear feet of roofline.
One of our dealers pulled out a previous install from a 12-volt competitor that had 15 power injection boxes on just the front of one home. 15 sets of wires through the fascia. 15 extra fail points. The same home on a TruLight 48-volt system needed zero injection boxes on the front.
See the install math at 16:36 in the videoWhy Higher Voltage Means LESS Heat in the Wire
P = V × I. Power equals voltage times current. To deliver the same amount of power, a higher-voltage system needs less current. Heat in a wire is determined by current squared times resistance (Q = I² × R), not by voltage. Halving the current cuts wire heat by 75 percent. Less heat at the connectors means less expansion and contraction over time, less stress on the components, and a longer service life.
Vicor, a major power-electronics manufacturer, publishes the math directly in their technical literature: “By increasing the bus voltage to 48V you can cut your distribution losses up to 75%, which dramatically reduces heat generation.” That is the industry consensus on 48-volt LED systems, and it is one reason commercial LED installations have been moving toward 48-volt as standard.
This is the same reason the entire North American power grid transmits electricity at hundreds of thousands of volts before stepping it down at the substation near your house. Higher voltage, less heat in the wire over distance. The same principle applies inside a permanent lighting run at a much smaller scale.
See the physics breakdown at 5:11 in the videoHonest Caveat: Not All 48-Volt Systems Are Equal
Voltage alone does not make a system good. A poorly engineered 48-volt system can absolutely be worse than a well-engineered 12-volt one. Higher voltage requires better voltage conversion, better protection circuitry, and a chip that was designed to handle it. A generic 48-volt fixture pulled off a wholesale site with a stock RGB app behind it is not the same product as a 48-volt system engineered end to end.
That is why our system pairs the 48-volt bus with the UCS7604 chip, 6 LEDs per node (3 RGB plus 3 dedicated warm white), and an app that was built for this hardware. You get the install simplicity, the long-run brightness consistency, and the chip that was designed for the higher-voltage RGBW generation. Voltage is one tool. The engineering around it is what makes it work.
Hear the "not all 48V is equal" caveat at 19:22Voltage Tier Comparison
| Spec | 5V | 12V | 24V | 48V (TruLight) |
|---|---|---|---|---|
| Power Injection Interval | Every 5-10 lights | Every 20-40 lights | Every 50-100 lights | Every 400+ lights |
| Typical Use | Indoor strip / DIY | Budget / older perm | Mid-range perm | Premium perm + commercial |
| Wire Heat (same brightness) | Highest | High | Moderate | Lowest |
| Long-Run Brightness Consistency | Poor | Needs injections | Better | Best |
| Truck Analogy | RC car | Standard pickup | Heavy-duty pickup | Semi-truck |
| Suitable for Full Home (Front + Back) | ||||
| Suitable for Commercial Buildings |
Why Lumens Marketing Can Mislead You
Lumens are a real unit of measurement, but how a company reports them is wide open. A cheap lumen meter and a premium lumen meter give very different readings. Distance to the source, angle, ambient light, and even the meter brand all affect the number. In the video, we hold a single light at different distances from a lumen meter and watch the reading swing from 100 to 800.
What actually drives brightness is current, not voltage alone. Higher-voltage systems can deliver more consistent current across a long run, which is why a TruLight roofline stays bright from the first fixture to the last. Lower-voltage systems experience voltage drop along the run, which dims the far end unless extra power injection points are added.
If a permanent lighting company leads their pitch with a high lumens number, ask at what distance, with what meter, and at what point on the run. The answer is the test.
See the lumen meter demo at 21:08 in the videoA Note on Misleading Marketing Claims
You will run into permanent lighting marketing that flips the physics. One published example: a 24-volt brand posted an article titled “Permanent Outdoor Lights: The Hidden Cost Of 48-Volt Lighting Systems” arguing that 48V systems “put a lot of power running through the wires, which creates a lot of heat” and that this leads to a shorter lifespan. That framing inverts P = V × I. Higher voltage means lower current at the same power, and lower current means less heat. We address that article directly in the video.
The point is not to single out any one company. The point is that voltage is one of the easiest specs to misrepresent in marketing copy, and you should read claims about it with the physics in mind. Ask any installer to explain why their voltage choice makes sense for your home, and what it actually changes about the install. A confident, specific answer with public data behind it is the test.
If you want a longer written walk-through of the safety, lifespan, and chip claims that get attached to voltage marketing, see our blog post Is 48-Volt Permanent Outdoor Lighting Safe?.
See this section of the video at 2:21Straight From the Video
“Higher voltage means less current. Less current means less heat. More efficient. Longer-lasting lights.”
“The reason we can offer a 100,000-hour warranty is because our voltage is higher, less heat, longer lasting light.”
“A poorly designed 48-volt system can still be worse than a great 12-volt system.”
“Lumens are a unit of measurement that cheap lights use to try and compete with higher-powered systems.”
Ready to See What 48V Looks Like on Your Home?
Get your instant quote and we will walk your home in person. We will show you where the controller goes, where the power injection lands, and exactly what a 48-volt install looks like on your specific roofline.