When planning outdoor lighting, you don't want lights that are too intense or too dim. Choose something too bright, and you'll suffer from glare and wind up with a front yard that resembles either a penitentiary or an opera house. If you select something too dim, you'll lose the convenience and security benefits of outdoor lighting. When selecting wattage, keep in mind the specific needs and dimensions of the area you will illuminate.
High Wattages (80 Watts and up)
If you're looking to flood your lawn with light, select lighting to accommodate bulbs with wattages of 80 or higher. According to the International DarkSky Association, an association devoted to fighting excessive light pollution, 100 watt and higher bulbs are appropriate for pedestrian areas, institutions, parking lots or roadways. Roadway lighting approved by the association may have a wattage of up to 400 watts. Such lighting is suspended high above the ground, features an opaque "night sky shield" cap and provides lighting for a broad area. For yards or gardens, the association's maximum recommended wattage is around 80 watts. Philips Lumec manufactures a number of 82 watt LED fixtures recommended for gardens or residences.
Mid-range Wattages (40 to 80 Watts)
To bathe a small yard or driveway in gentle to moderate light, select a lighting fixture that accommodates 40 to 80 watt bulbs. Many of the lighting devices approved by the International DarkSky Association comply with this general range. To extend this level of wattage over a broad area, select a model that mounts from a post, or mount it from an arm extending from a high wall. With this range of wattages, you'll still want to avoid mounting the lights directly adjacent to any home windows to avoid unpleasant nighttime glare.
Low Wattages (up to 40 Watts)
Using low wattage bulbs can reduce your energy consumption, minimize light pollution and target those areas you most want illuminated. In addition, while your solar lighting options are extremely limited at higher wattages, you can much more easily find a solar lamp at a low wattage. To illuminate a footpath or encircle an outdoor seating area, stagger a series of low wattage lights to provide several small, overlapping rings of light. For example, a series of 18 or 20 watt bulbs provides plenty of power to illuminate a footpath, shine light on a doorway or accent a flowerbed. As with any kind of light source, direct the light to take full advantage of its wattage. In the case of footpath lighting, as for overhead pole lighting, select a lamp with an opaque cap to direct all light downward and avoid any waste or glare.