Two of the most commonly used voltages are line and low voltage. You probably know enough about lighting to know these systems are different – but this only the beginning. By understanding how they’re different and what each system does, you can make a more informed decision with your next residential or commercial lighting purchase.
What Does What?
A line voltage system uses electricity directly as it flows through an electrical panel, outlet or junction box. This system typically puts out a standard 120 volts of electricity in the United States and Canada. (This may be higher for some commercial buildings.) A low voltage system has a transformer or driver to lower the current, typically to either 12 or 24 volts. This device can be installed directly into a low voltage light fixture or be set up remotely.
Lamp Size & Styling
A line voltage lamp is generally larger as this design is needed to handle the higher current. This means your options are typically limited to traditional lighting fixtures and lamps such as A19 and PAR bulbs. Low voltage bulbs such as MR16 and JC/Wedge lamps tend to be smaller in size, therefore low voltage fixtures can be of a smaller profiler to use these smaller bulbs. This is why low voltage lighting is often the preferred choice where the style or size of the fixture is very important, such as track lighting, accent lighting, and landscape lighting.
Operating Costs & Energy Efficiency
Initial costs for a line voltage system are typically much less than for low voltage. The price of lamps, fixtures and installation are noticeably lower, and you also don’t have to pay for a transformer or driver. (And transformers eventually need be replaced.) Dimming fixtures are often more expensive for low voltage systems as well, as you need to also use a dimming-capable transformer or driver, in addition to the dimming-capable fixture…then make sure the two are compatible with each other. This start-up cost can be a big factor if you’re on a budget.
Once you’re up and running, the low voltage setup CAN cost less to operate. This is largely due to their efficiency level. Historically, while a 100-watt line voltage bulb and low voltage bulb use the same amount of energy to operate, the latter had significantly higher light output, meaning you can use a lower-wattage lamp or fewer lamps. Low voltage lamps also last much longer, saving money on replacement and labor. If you use your lights frequently, you may be able to make the initial expense up over time. But moving forward, the advent and proliferation of LED technology has adjusted some of these concepts. Line voltage LED fixtures can last just as long and be just as efficient as their low voltage LED counterparts.
Historically speaking, high voltage lamps emitted a light that was soft and diffused, while low voltage lamps had a clearer and sharper light. However, modern LED light fixtures have made it possible to produce many types of light with each system. Especially if you have an integrated fixture, you can now get high-quality and diverse light output with either voltage type.
Line voltage systems are advantageous if you have a large amount of light fixtures wired to a single circuit or if you are covering a great distance or area with light. With low voltage systems, capacity and distance are limited. One issue to be mindful of is “voltage drop”. This is the degree to which the voltage in the system is reduced from the start to the end due to the size and length of the conductors in the lighting setup. The other issue is the wattage of the transformer or driver that is powering the low voltage system. Due to these two factors, low voltage systems are typically only able to serve smaller areas using lighter electrical loads.
Lighting Safety Factors
Low voltage fixtures are safer overall than line voltage. The lower current flow means a lower risk of an electrical shock and that shocks are less likely to cause serious damage. In fact, some locations require low voltage lights in residential and/or commercial locations. Check your local building codes to see what is mandated. There are safety risks associated with installing either system, so be diligent no matter which one you choose.
A line voltage system has several advantages. There are fewer upfront costs installation takes less time, and it can light large areas. But for many homeowners and LED light users, the additional light fixture options, better aesthetic designs due to the smaller size, and safer operation are worth giving low voltage a consideration.