Chapter 15 Key Takeaways: Lighting

The LED Revolution Is Complete

Standard incandescent bulbs are no longer manufactured for general residential use. LED replacements use 85–90% less energy, last 15–25 years (vs. 1 year for incandescent), and have improved dramatically in light quality. A full LED conversion in a typical home pays back in months, not years. There is no reason to use anything other than LED for standard residential lighting.

Shop by Lumens, Not Watts

Watts measure energy consumption. Lumens measure light output. Use lumens when comparing bulbs — an 800-lumen LED and an 800-lumen incandescent produce the same amount of light, but the LED does it with 9 watts instead of 60.

Color Temperature and CRI Are Separate Qualities

• Color temperature (Kelvins): 2700K = warm/yellow. 3000K = soft white. 4000K = cool white. 5000K+ = daylight/blue. Use 2700K for bedrooms and living rooms; 3000K for kitchens and bathrooms.
• CRI (Color Rendering Index): 80–100 scale, how accurately the light reveals colors. Use 90+ CRI in kitchens and bathrooms. The difference between CRI 80 and CRI 95 is visible and significant in spaces where color accuracy matters.
• Keep color temperature consistent within each room — mismatched color temperatures create visual dissonance.

Non-IC Recessed Lights in Insulated Ceilings Are a Problem

Non-IC recessed fixtures in contact with attic insulation are a fire hazard and a major source of air leakage. The fix is LED retrofit kits — IC-rated, sealed inserts that snap into existing cans. Cost: $15–30 per fixture; installation is genuinely DIY, approximately 10 minutes each.

Dimmer Compatibility Is a Real Issue

LED bulbs require LED-compatible dimmers. Old TRIAC dimmers designed for incandescent loads will cause flickering, buzzing, limited range, and drop-out with LED bulbs. The fix: replace the dimmer with an LED-compatible model ($25–65). Look for dimmers labeled "CL," "LED/CFL compatible," or similar. Use the manufacturer's online compatibility tool to verify your specific bulb/dimmer combination.

Ceiling Fan Direction Matters by Season

• Summer (counterclockwise): Blades push air down. You feel a breeze. Makes the room feel cooler.
• Winter (clockwise): Blades pull air up, pushing warm ceiling air down the walls. Reduces heating costs in high-ceiling rooms.
• Change direction when seasons change. The switch is on the motor housing.

Outdoor Lighting Serves Safety and Security

Photocell controls provide dusk-to-dawn operation (best for consistently used entry points). Motion sensors activate on presence (best for security and infrequently used areas). Timer controls work well for landscape and aesthetic lighting. All outdoor fixtures must be rated for their exposure level: damp location for covered areas, wet location for exposed areas.

Troubleshooting Sequence

1. Try a new bulb
2. Check for a tripped breaker
3. Check for a tripped GFCI upstream on the circuit
4. Check connections at switch and fixture (power off)
5. If multiple rooms flicker simultaneously, call an electrician — possible main panel issue

DIY vs. Professional Boundaries

DIY: Bulb swaps, GFCI resets, dimmer replacement, LED retrofit kit installation, ceiling fan installation (where fan-rated box exists), fixture swaps at existing locations.

Professional: Adding circuits or fixtures requiring new wiring, any panel work, troubleshooting unknown wiring, running new circuits for ceiling fans without existing wiring.

Cost Reference