The transformer is the single most important component of any low voltage landscape lighting system. It converts standard 120V household power to a safe 12V output, powers every fixture on your property, and — when chosen wisely — makes your system reliable, expandable, and easy to control.
In this buying guide we cover how to size a transformer, the features that matter, and our top picks for 2026 from the brands we carry.
How a Low Voltage Transformer Works
A landscape lighting transformer is a step-down device. It takes 120V AC from a standard GFCI outdoor outlet and reduces it to 12V AC. The 12V output feeds through direct-burial landscape wire to each fixture on the circuit.
Because the output is only 12 volts, the entire system is classified as a Class 2 low-voltage circuit under the NEC — safe to install without a licensed electrician in most jurisdictions.
How to Size Your Transformer
Sizing is straightforward:
- Add up total fixture wattage. Count every fixture on the circuit and sum their individual wattages. With modern LEDs, most path lights draw 2 to 5 W and most up lights draw 4 to 8 W.
- Apply a 25 percent safety buffer. Multiply total wattage by 1.25. Running a transformer at or near 100 percent capacity shortens its life and can cause voltage fluctuations.
- Round up to the next available size. Common sizes are 100 W, 150 W, 300 W, and 600 W.
Quick Sizing Chart
| Number of LED Fixtures (3 W avg.) | Total Wattage | With 25% Buffer | Recommended Transformer |
|---|---|---|---|
| 1 to 25 | 3 to 75 W | 4 to 94 W | 100 W |
| 26 to 40 | 78 to 120 W | 98 to 150 W | 150 W |
| 41 to 80 | 123 to 240 W | 154 to 300 W | 300 W |
| 81 to 160 | 243 to 480 W | 304 to 600 W | 600 W |
Pro tip: If you plan to add more fixtures within the next year or two, size up one level now. It is far easier to buy a slightly larger transformer upfront than to replace one later.
Features to Look For
Multi-Tap Terminals
Premium transformers offer multiple output terminals at different voltage taps (12V, 13V, 14V, 15V). Higher taps compensate for voltage drop on long wire runs, ensuring every fixture receives close to 12V.
Built-in Timer
A built-in timer lets you program on/off schedules. Mechanical timers are simple and reliable. Astronomical timers automatically adjust for sunrise and sunset throughout the year — the most hands-off option.
Photocell
A photocell senses ambient light and turns the transformer on at dusk. Combined with a timer, this gives you fully automatic operation: on at dusk, off at your programmed time.
Stainless Steel vs. Polycarbonate Enclosure
Stainless steel enclosures are more durable and better at dissipating heat, making them the preferred choice for larger systems. Polycarbonate is lighter and more affordable — a good fit for smaller residential installations.
Circuit Breaker Protection
Quality transformers include a built-in circuit breaker that trips if there is a short, protecting both the transformer and your wiring.
Our Top Transformer Picks for 2026
Best for Small Projects: Pro-Trade TR2 100W Polycarbonate
The Pro-Trade TR2 100W (PT-TR2-100PC) is an excellent entry-level transformer. It ships with a built-in timer and photocell module, so it is ready for automatic dusk-to-off operation right out of the box. The lightweight polycarbonate housing keeps cost down, and 100 W is enough for up to 25 LED fixtures at 3 W each.
Best for: Homeowners installing their first lighting system with fewer than 25 fixtures.
Best Value All-Rounder: Sollos 100W Black Coated with Photocell Timer
The Sollos 100W Transformer (997012) combines a durable black-coated steel enclosure with an integrated photocell and timer. It punches above its price point with solid build quality and clean aesthetics that blend into any landscape.
Best for: Budget-conscious buyers who still want a metal enclosure and automatic scheduling.
Best Mid-Range Workhorse: Pro-Trade TR1 150W Stainless Steel
The Pro-Trade TR1 150W (PT-TR1-150SS) is built for the long haul. The marine-grade stainless steel enclosure resists corrosion in humid and coastal environments. At 150 W, it supports up to 40 LED fixtures — perfect for a medium-sized residential property with paths, beds, and a few accent lights.
Best for: Mid-size residential projects, especially in coastal or high-humidity climates.
Best for Large Residential Projects: Pro-Trade TR1 300W Stainless Steel
The Pro-Trade TR1 300W (PT-TR1-300SS) doubles the capacity while keeping the same premium stainless housing. Multi-tap terminals let you compensate for voltage drop across multiple zones. If your property has a long driveway, pool area, and extensive garden beds, the 300 W handles it all on one transformer.
Best for: Larger homes with 40 to 80 fixtures across multiple zones.
Best for Estates and Commercial: Pro-Trade TR1 600W Stainless Steel
The Pro-Trade TR1 600W (PT-TR1-600SS) is the flagship. With 600 watts of capacity and multiple independently fused terminal blocks, it powers sprawling estate properties and light-commercial installations. Despite the power, it runs cool thanks to the oversized stainless steel enclosure.
Best for: Estate homes, HOA common areas, restaurants, and commercial landscapes with 80+ fixtures.
Transformer Comparison at a Glance
| Model | Wattage | Enclosure | Timer | Photocell | Best For |
|---|---|---|---|---|---|
| Pro-Trade TR2 100W | 100 W | Polycarbonate | Yes | Yes | Small / DIY |
| Sollos 100W | 100 W | Coated Steel | Yes | Yes | Value pick |
| Pro-Trade TR1 150W | 150 W | Stainless Steel | Add-on | Add-on | Mid-size residential |
| Pro-Trade TR1 300W | 300 W | Stainless Steel | Add-on | Add-on | Large residential |
| Pro-Trade TR1 600W | 600 W | Stainless Steel | Add-on | Add-on | Estate / commercial |
Installation and Placement Tips
- Mount near a GFCI outlet. The transformer must plug into a ground-fault protected outdoor receptacle.
- Keep it off the ground. Mount the transformer at least 12 inches above grade to protect it from standing water and irrigation spray.
- Allow ventilation. Do not enclose the transformer in a tight box — it generates heat and needs airflow.
- Use multi-tap terminals. For runs over 50 feet, connect to the 13V or 14V tap to offset voltage drop so the fixture still receives close to 12V.
- Pair with quality wire. Invest in direct-burial rated 12/2 wire or 10/2 wire for longer runs.
Frequently Asked Questions
What size transformer do I need for 10 LED path lights?
Most LED path lights draw 2 to 5 W. At an average of 3 W each, 10 fixtures total 30 W. Apply a 25 percent buffer (30 x 1.25 = 37.5 W) and a 100W transformer is the right choice.
Can I put a transformer inside my garage?
Yes, as long as it plugs into a GFCI-protected outlet and the low voltage wire exits through a proper wall penetration. Indoor mounting actually extends the transformer life by protecting it from weather.
Do I need a separate transformer for front and back yard?
Not necessarily. A single higher-wattage transformer with multi-tap terminals can feed multiple zones. However, if the total wire run from front to back exceeds 150 to 200 feet, two smaller transformers — one for each area — will deliver more consistent voltage.
How long do landscape lighting transformers last?
A quality stainless steel transformer typically lasts 15 to 20 years or more. Polycarbonate models average 8 to 12 years. In both cases, avoid running the transformer at more than 80 percent capacity to maximize lifespan.
Shop All Transformers
Browse our complete collection of low voltage landscape lighting transformers to find the perfect match for your project. Need help choosing? Check out our Low Voltage Landscape Lighting 101 guide for a full system overview, or browse our lighting kits that include a transformer, fixtures, and wire in one box.