Cool Led Landscape Lighting Wattage References. Furthermore, bulbs with 40 to 75 watts are ideal for outdoor fixtures,. Web again, if you want to connect twenty landscape lights to a low volt transformer, and the lights are pulling 4w / 7va / 35 watts of halogen power draw on the system, you would need a 300 watt transformer.
The bulbs also last much longer. An led bulb uses approximately 85% less energy than a halogen bulb. Roadway lighting may have a wattage of up to 400 watts.
