Planner
Cozy lighting layers planner
This is for anyone whose living room or bedroom feels flat or harsh after dark and who wants a number to aim for before buying lamps or bulbs. Tell it the size of the room and how bright you like the evening to feel. It returns a lumen target, a split across three layers of light and a minimum number of lamps. It updates as you type, and nothing leaves your device.
2,750 lumens in total
Worked example (shown when scripts are off): a 14 by 12 foot living room with medium walls and a balanced mood needs about 2,750 lumens in all, split into roughly 1,400 ambient, 850 task and 500 accent, from at least four lamps.
Before you decide
This is a starting point, not a lighting design. Put the main lamps on dimmers so you can lower the result, and keep wiring changes with a licensed electrician.
How the planner works
Lumens measure how much light a bulb gives off, and the number is printed on the bulb box. Lighting guides that summarize Illuminating Engineering Society recommendations give about 10 to 20 lumens per square foot for living rooms and bedrooms. The planner multiplies your floor area by 10 for a soft mood, 15 for balanced and 20 for brighter. It then multiplies by 1 for light walls, 1.1 for medium and 1.25 for dark, because dark surfaces absorb more light. Those wall multipliers are planning assumptions, not published standards. The result is rounded to the nearest 50 lumens, with a floor of 300.
The total is split across the three layers described in the warm lighting guide. Living rooms get 50 percent ambient, 30 percent task and 20 percent accent. Bedrooms get 45, 30 and 25. These splits are also assumptions, chosen to match how those rooms are usually used: bedrooms lean on soft accent and bedside light rather than overhead light.
The lamp count is the larger of three or one lamp for each 700 lumens of target. A cozy room is made of several moderate sources at different heights, not one bright one, which is why the planner never recommends fewer than three.
Worked example
A 14 by 12 foot living room is 168 square feet. With a balanced mood and medium walls the factor is 15 times 1.1, or 16.5 lumens per square foot, so the target is 168 times 16.5, about 2,750 lumens. That is 1,400 ambient, 850 task and 500 accent. At 700 lumens per lamp that means four lamps, for example a floor lamp that bounces light off a wall, a reading lamp beside the sofa, a table lamp on a side table and a small shelf lamp.
Warm-bulb rules to go with the number
- Choose bulbs labeled 2700K or lower for every lamp in the room. Amber 2200K to 2400K bulbs suit a few accent lamps. Do not mix them with 4000K or higher bulbs.
- Read lumens on the box rather than watts. A bedside lamp is usually comfortable at about 400 to 600 lumens, a table lamp at 400 to 800 and a shelf lamp at 100 to 300.
- Check that a bulb says dimmable, and use a dimmer that is rated for LEDs, or the bulb may flicker or buzz.
- Never exceed the maximum wattage printed on a lamp.
- Turn the overhead light off for the evening if you can. It flattens the room and casts shadows downward.
Limits
The planner ignores daylight because it is for evenings. It also ignores ceiling height, sloped ceilings and shade color, and a deep opaque shade can block a lot of light. Published lumen guidance differs between sources, so treat the number as a range to aim for within about 20 percent either way. This is general information, not professional lighting advice. Hire a licensed electrician for any change to house wiring or switches.
Where this comes from
We checked lighting guides that summarize the Illuminating Engineering Society's residential recommendation of 10 to 20 footcandles, which equals lumens per square foot, for living rooms and bedrooms. We did not read the original standard, so that figure is secondary. The bulb color, lumen ranges per lamp and the three layers come from the site's own warm lighting guide. The wall multipliers, layer splits and one lamp per 700 lumens are our assumptions.