Lighting Reference for Interior Designers
A quick reference for planning light: how bright each space should be, what colour of light suits it, and how to size and hang decorative fixtures over tables and islands.
Light levels by space
| Space | Footcandles | Lux | Notes |
|---|---|---|---|
| Living room | 10–20 | 110–220 | Ambient; add lamps for reading |
| Dining room | 10–20 | 110–220 | About 10 on the table for everyday dining, 20 for homework or work |
| Kitchen, general | 30–40 | 320–430 | Counters and sink 50 or more, usually from task lighting |
| Bedroom | 10–20 | 110–220 | About 30 for reading in bed |
| Bathroom | 20–50 | 220–540 | About 20 vertical at the face at a vanity |
| Home office | 20–50 | 220–540 | 30 for screen work and normal print |
| Hallway or entry | 5–20 | 50–220 | |
| Open office | 30–40 | 320–430 | 30 for screen work in IES task tables |
| Conference room | 30 | 320 | 30 on faces for video calls |
| Restaurant, casual | 10 | 110 | Fast food about 20 |
| Restaurant, fine dining | 3 | 30 | Low ambient with focused light on tables |
| Café or coffee shop | 10 | 110 | |
| Hotel lobby | 10 by day, 5 at night | 110 / 50 | Reception desk about 40 |
| Retail | 20–40 | 220–430 | Furniture stores about 20; accent displays 3–10 times ambient |
Commercial values follow the IES Lighting Handbook, 10th edition, as compiled by utility lighting programs. Residential ranges come from IES-based guidance (Penn State) and reported values from ANSI/IES RP-11. Newer IES recommended practices may differ. IES targets assume most occupants are 25–65: double them where most are over 65, and halve them where most are under 25. One footcandle is one lumen per square foot, about 10.8 lux.
From light levels to lumens
Multiply the floor area by the target footcandles to get the lumens that need to reach the work surface: a 12 × 14 ft dining room at 10–20 fc needs 1,680–3,360 lumens there. A common rule of thumb is that about half of a fixture’s lumens arrive, after losses to walls, ceiling, shades and ageing, so plan to install about twice that; the real share depends on the fixture and the room. Dark finishes, tall ceilings and deep shades need more. Our lighting calculator does this for you and counts fixtures.
Colour temperature
| Colour temperature | Looks like | Typical uses |
|---|---|---|
| 2200–2700 K | Warm, candle to incandescent | Restaurants, bars and lounges; dimmed evening light |
| 2700–3000 K | Warm white | Living rooms, bedrooms, dining and hospitality |
| 3500–4100 K | Neutral white | Kitchens, offices, retail and work areas |
| 5000–6500 K | Cool, bluish daylight | Task lamps, garages and spaces that need colour checking |
Ranges after ENERGY STAR; typical uses after Energy Trust of Oregon, which suggests about 2700 K for living rooms, 3500 K for kitchens and 5000 K for reading lamps. California’s Title 24 limits high-efficacy residential light sources to 4000 K or less.
Colour rendering
- CRI 80 is the usual minimum for general lighting.
- CRI 90 or more, with an R9 (saturated red) value of 50 or more, is the premium tier, and what California’s Title 24 (Joint Appendix 8) requires of high-efficacy residential sources. Use it wherever wood, fabric, food or skin tones matter.
- CRI predicts preference only loosely. The newer TM-30 metrics (fidelity Rf and gamut Rg) describe colour quality more fully.
Sizing decorative fixtures
| Rule of thumb | How to use it |
|---|---|
| Chandelier for a room | Room length + width in feet = diameter in inches. A 12 × 14 ft room takes about a 26" (66 cm) fixture. |
| Chandelier over a table | One-half to two-thirds of the table width, and at least 12" (30 cm) narrower than the table. |
| Height over a table | 30–36" (76–91 cm) from tabletop to the bottom of the fixture under an 8 ft ceiling; add about 3" (8 cm) for each extra foot of ceiling. |
| Pendants over an island or table | 30–36" (76–91 cm) above the surface, about 24–30" (61–76 cm) apart centre to centre for small shades. One pendant up to about 4 ft of length, two to about 7 ft, three beyond, adding one for about every 3 ft past 10 ft. Keep the outer pendants 12–20" (30–51 cm) in from the ends. |
| Fixtures over walkways | Designers keep the bottom of a fixture at about 7 ft (213 cm). The ADA requires at least 80" (2,030 mm) of headroom on circulation paths, and the BC Building Code 2,050 mm (81") in exits and access to exits. |
Fixture rules come from lighting manufacturers and retailers; no standards body publishes them, so treat them as starting points and check the scale on site.
