Lights Out Kirkwood

Choosing the Right Bulb: a Kelvin Guide

The number that matters most on a bulb box isn’t watts or lumens — it’s the color temperature, measured in Kelvin (K). Lower is warmer, amber, and gentler on the night. Higher is colder, bluer, and worse for skyglow, sleep, and wildlife.

What to buy for outdoors

Kelvin	Looks like	Verdict for outdoor use
1800–2200K	Candle / amber	Ideal. Almost no blue light. Best near parks, streams, and bedrooms.
2700–3000K	Warm white	Recommended maximum. Comfortable, good visibility, limited skyglow.
3500–4000K	Neutral / cool white	Use caution. Noticeably bluer — more glare and skyglow. Avoid outdoors.
5000K+	“Daylight,” blue-white	Avoid outdoors. Harsh and blue-rich — worst for sky, sleep, and wildlife.

DarkSky recommends 3000K or lower for all outdoor lighting, and 2200K or warmer near parks, streams, and wildlife.

How to read a bulb box in 10 seconds

Find the Kelvin number or the words “soft white” / “warm white” (good) vs. “daylight” / “bright white” (too blue outdoors).
Aim for 2700K at home; go 2200K for a porch near trees or a garden.
Watts measure energy, lumens measure brightness — a warm bulb can be plenty bright. You rarely need more than 400–800 lumens outdoors.
Pair a warm bulb with a shielded, downward fixture and a motion sensor for the full effect.

A note on your streetlights

Most area streetlights are owned by Ameren (some by the City of Kirkwood). Ameren’s LED roadway standard is around 3000K, and they will fit shields on lights that trespass into a home. To report a glaring or broken streetlight, use Ameren’s form or KirkwoodKonnect — see lightsoutkirkwood.org.

More at lightsoutkirkwood.org — including a live slider that shows exactly how each Kelvin value looks. Guidance: DarkSky International.