Measuring Your Lighting Needs

The NEC calls for a minimum calculation for general lighting and receptacle loads of three watts per square foot of living space. This comes out to approximately one circuit every 575 square feet. That doesn’t amount to a lot, but remember, electrical codes only establish minimum standards. In reality, you’ll want lighting everywhere.
Consider the different areas of your house and their individual needs:

• Kitchen. Overhead lighting, natural light from windows and sliding doors, work light over counters, a light over the stove.
• Bathrooms. Primarily lights over the sink(s) and lights over the bathtub and toilet, depending on the size of the room.
• Dining room. A hanging light over the table, recessed ceiling lights, or possibly wall sconces. This room often has a dimmer switch to tone down the light.
• Bedrooms. Children’s rooms often get ceiling lights. Master bedrooms might depend more on reading lamps and switch-controlled receptacles, although large rooms can use recessed ceiling lighting as well.
• Hallway. You might want a long track light to highlight artwork on the walls.
• Garage. At least one light per bay over the hood of the cars. It’s even better to add one or two at the other end so the trunks are illuminated.
• Basement. Depends on whether the space is finished or unfinished. In either case, you want at least enough ceiling light to cover the entire area thoroughly, leaving no dark spots.
• Closets, storage rooms. At least one ceiling light.
• Outdoors. At a minimum, one light over each entry door and over the garage doors. It’s even better to consider lights to line walkways and illuminate gardens or security lighting for back and side yards.

Your use of a room obviously will determine your choice of lighting fixtures, their locations, and their number. A single fluorescent ceiling light will fulfill all the working requirements of most closets because the requirements are pretty basic: to shed enough light for you to identify and choose your clothes. A kitchen, on the other hand, requires all kinds of light for a modern homeowner. You need lights over counters for close work so you can chop, dice, and mince vegetables instead of your fingers. Overhead lights enable you to read the newspaper and get a better look at what’s hiding in the back of your pantry. A dimmer-controlled hanging light over the eating area lets you tone things down for a late-night meal. Anywhere you’ve got a wall, ceiling, or floor, you can install a light. It’s simply a matter of extending a circuit or running a new one and choosing your fixtures. The science of lighting is a little more complicated.