How much lighting should you plan for when you’re building or renovating a home? The best answer is that it depends on differing factors. Yes, there are a variety of formulas to help you determine how much lighting to install, but first, consider the following:
- How big is the room?
- How many windows does it have, and what is their orientation? Obviously, east- and west-facing windows will provide abundant sunlight.
- What size are the windows? A bright, open picture window will let in plenty of sunlight during the day, so will the room require bright lighting at night?
- How open is the home? Some homes have twists, turns and closed-up, tight spaces that may require extra lighting to eliminate gloomy pockets.
- Do you prefer brightly lit interiors or do you lean more to softer illumination?
- What’s the purpose of the room? For instance, you may need more lighting in the kitchen for epicurean paring, dicing, slicing and trimming, while you want a softer, more romantic lighting scheme in the bedroom.
Once you’ve considered all these questions, you’re ready to calculate the amount of light needed per room.
Calculating Lighting Needs
Lighting providers use different methods to calculate lighting needs. With the following method, you will need square footage, as well as a measurement for foot-candles and lumens.
First, determine the square footage of the room by multiplying length times width in feet. For example, a room that’s 20 feet by 15 feet is 300 square feet in area.
Now you need foot-candle measurements for each room. A foot-candle is how bright light is a foot away from the source. Foot-candle needs vary according to the use of the room. Bathrooms and kitchens usually need more foot-candles than living rooms or bedrooms. Consult a lighting expert for general foot-candle needs per each room.
Next, you’ll need to figure out how many lumens are needed per room. The lumen is a measurement that conveys how much light is reaching what you want to illuminate. Multiply square footage of the room by the foot-candle measurement. So, for a 300-square-foot living room, needing 10-20 foot-candles, you’d need 3000-6000 lumens.
When shopping for light fixtures, look on the label for the output of lumens they can provide.
Room-by-Room Lighting Tips
These room-by-room tips can help you assess your lighting needs more accurately.
Kitchen (5000-10,000 lumens). This multi-purpose room often presents challenges, as you light for different purposes, from food prep to breakfast to making out bills. Place recessed lights on the sides of the ceiling to reduce shadows. Install lights under the cabinet to illuminate tasks.
Bedrooms (2000-4000 lumens). Place table lamps for reading or mood lighting; install overhead fixtures for cleaning and other tasks.
Bathrooms (4000-8000 lumens). Tub/shower areas can be murky; install a light overhead. Installing lights along the sides of mirrors is better than ceiling fixtures for illuminating shaving or applying makeup.
Living room. Plan to use several different types of lighting: lamps for reading; accent lighting (spotlights and picture lights) for artwork; and ambient lighting, angled away from seating.
Dining room (3000-6000 lumens). Install adjustable recessed lights that you can angle to highlight table decorations. Avoid positioning lights over dining chairs to prevent casting shadows on diners.
Office (3000-6000 lumens). Use portable lamps for computer stations so you can angle them and avoid glare on the monitor. Angling recessed lighting toward walls makes the room look brighter.
Remember: the calculating formula is just a guideline. Talk to a lighting expert in depth about your home’s lighting needs before you put those holes in the drywall.