How to Read an LED Spec Sheet: Lumens, CRI, Wattage & More

LED spec sheets are packed with numbers that mean nothing to most buyers. But understanding five key specs will prevent you from buying the wrong product — and save you money. Here's a no-jargon guide.

The 5 Specs That Actually Matter

1. Lumens (lm) — How Bright It Is

Lumens measure total light output. Forget wattage for measuring brightness — that's an old incandescent habit. Two 10W LED fixtures can produce very different lumen levels depending on quality.

Lumen Range	Equivalent Feel
450 lm	40W incandescent
800 lm	60W incandescent
1,100 lm	75W incandescent
1,600 lm	100W incandescent

What to look for: Match lumens to your application. Under-cabinet strips need 300-500 lumens per metre. A 6-inch pot light should deliver 900-1,200 lumens. A high bay needs 15,000+ lumens.

2. Wattage (W) — How Much Energy It Uses

Wattage is energy consumption, not brightness. Lower wattage at the same lumen output = more efficient fixture.

Old Way	New Way
"I need a 60-watt bulb"	"I need 800 lumens"
"Brighter = more watts"	"Brighter = more lumens"

3. Efficacy (lm/W) — Efficiency Rating

Efficacy = lumens ÷ watts. This is the most important number for comparing LED products.

Efficacy	Rating
Below 80 lm/W	Poor (avoid)
80-100 lm/W	Acceptable
100-130 lm/W	Good
130-150 lm/W	Excellent
Above 150 lm/W	Premium

Our LED panels achieve 110+ lm/W, and our high bays reach 150 lm/W — both qualifying for DLC listing.

4. CRI (Colour Rendering Index) — Colour Accuracy

CRI measures how accurately colours appear under a light source, on a scale of 0-100. Natural sunlight is CRI 100.

CRI	Quality	Application
60-70	Poor	Avoid for any occupied space
70-80	Acceptable	Parking lots, storage, utility
80-90	Good	Offices, retail, residential
90-95	Excellent	Kitchens, bathrooms, galleries
95-100	Reference	Photography, medical, art

The practical impact: Under CRI 70, red apples look dull and skin tones appear grey. Under CRI 90+, colours look vivid and natural.

What to look for: Minimum CRI 80 for any residential or office application. CRI 90+ for kitchens, bathrooms, and retail.

5. CCT (Correlated Colour Temperature) — Warm vs Cool

Measured in Kelvin (K). Not related to brightness.

CCT	Appearance	Best For
2700K	Warm amber	Bedrooms, restaurants
3000K	Warm white	Living rooms, hospitality
3500K	Neutral warm	Transitional spaces
4000K	Neutral white	Kitchens, offices, retail
5000K	Daylight	Garages, workshops, industrial
6500K	Cool blue-white	Rarely recommended

Read our full colour temperature guide →

Secondary Specs Worth Checking

Beam Angle

How wide the light spreads from the fixture.

• Narrow (15-30°): Spotlights, accent lighting
• Medium (40-60°): Track lights, display
• Wide (90-120°): General illumination (pot lights, panels)

IP Rating

Ingress Protection against dust and water.

• IP20: Indoor dry only
• IP65: Splash resistant (kitchen, covered outdoor)
• IP67: Temporary submersion (exposed outdoor)

Dimming Compatibility

• Phase dimming (TRIAC): Common residential dimmers
• 0-10V dimming: Commercial/industrial standard
• Non-dimmable: No dimming possible (avoid for residential)

Lifespan (L70)

Rated in hours to L70, meaning the point where output has declined to 70% of initial lumens.

• 30,000 hours: Budget products
• 50,000 hours: Standard quality (our panels and pot lights)
• 100,000 hours: Premium commercial

Certifications

• ETL / cUL: Required for legal installation in Canada
• DLC: Required for utility rebates (commercial)
• ENERGY STAR: Efficient residential products
• IC Rated: Safe for insulation contact

Red Flags on Spec Sheets

🚩 No ETL or UL marking — Illegal to sell or install in Canada 🚩 CRI not listed — Probably below 70 🚩 Lumens way higher than similar products — Likely measured at initial turn-on, not stabilized 🚩 No warranty information — Manufacturer doesn't stand behind the product 🚩 "Equivalent to" wattage claims — Meaningless without lumen data

Our Products — Key Specs

Product	Lumens	Watts	Efficacy	CRI	CCT
4" Pot Light	750 lm	9W	83 lm/W	80+	3000-5000K
6" Pot Light	1,050 lm	12W	87.5 lm/W	80+	3000-5000K
2x4 Panel	5,500 lm	50W	110 lm/W	80+	4000-5000K
UFO High Bay 150W	22,500 lm	150W	150 lm/W	80+	5000K

All specs verified and available at saferlighting.ca.

FAQ

Is higher CRI always better? For visual comfort and colour accuracy, yes. But CRI 90+ fixtures tend to cost more and may be slightly less energy-efficient. CRI 80+ is the sweet spot for most applications.

Why do some LEDs look different at the same Kelvin rating? Manufacturing tolerance. Cheaper LEDs have wider CCT bins (variation). Quality manufacturers like ours maintain tight binning so fixtures match closely when installed side by side.

What's the difference between lumens and lux? Lumens measure total light output from a fixture. Lux measures light intensity at a surface (lumens per square metre). You need both — lumens tells you what you're buying, lux tells you if the room is bright enough.

Should I care about power factor? For residential, no. For commercial with many fixtures, power factor affects your electricity bill. Look for power factor above 0.9 for commercial installations.