There have been significant changes in lighting in recent years due to the introduction of energy-efficient CFL (compact fluorescent) and LED (light-emitting diode) bulbs. Familiar old incandescent bulbs are becoming obsolete as their energy-hogging habits and wattage ratings are replaced by high-efficiency bulbs with more accurate lumens ratings.
Here’s a guide to understanding the differences between watts and lumens and navigating the lighting changes.
Watts Vs. Lumens
To start, what is the difference between a watt and a lumen?
Watts measures electricity usage. They show how much power a bulb draws but not its brightness.
With incandescents, wattage correlates with brightness. A 100-watt bulb produces about 100 lumens per watt or 1,000 lumens, giving consumers a general sense of brightness.
However, wattage ratings are now less applicable. CFLs and LEDs use fewer watts for the same light. Each type has different lumens-per-watt efficiency, so wattage alone does not show brightness. The goal is bulbs that use fewer watts to produce more light.
Lumens measure a bulb’s visible light output. Lumens show brightness regardless of the light source.
One lumen is roughly the light of one candle shining on a one-foot square from one foot away. A 60-watt incandescent bulb produces around 800 lumens. Bulbs between 1,000 and 2,000 lumens are good for task lighting.
Since lumens show perceivable brightness, they allow direct brightness comparisons between bulb types. Lumens give a more accurate way to shop for bulbs.
Lumens Per Watt
The lumens-per-watt rating shows a bulb’s light efficiency. It measures lumens produced per watt of electricity used. The higher the lumens-per-watt, the more efficient the bulb.
Incandescents produce around 10 to 20 lumens per watt. CFLs range from 50 to 70. LEDs now achieve 60 to 100-plus.
When shopping for bulbs, look at lumens-per-watt to find the most efficient for your needs. The rating is an average, as efficiency decreases over time.
The Phase-Out of Incandescents
Due to low efficiency, old incandescent bulbs are being phased out under new standards. Most will disappear from shelves over the next few years.
Energy-efficient LED and CFL bulbs will become the norm for home lighting. LEDs last 25 times longer than incandescents while using less energy. CFL bulbs have a number of benefits that make them a bright idea for going green in many homes.
ENERGY STAR Qualification
The ENERGY STAR rating is an easy way to find efficient bulbs. To qualify, bulbs must meet strict lumens-per-watt requirements from the U.S. Environmental Protection Agency.
Below are the minimum criteria for ENERGY STAR bulbs:
ENERGY STAR bulbs meet efficiency standards, so wattage indicates approximate brightness. ENERGY STAR makes it easy to find efficient CFL and LED replacement bulbs.
While lumens show brightness, they don’t describe light quality and color. These are other factors to consider when choosing bulbs:
- Beam Spread: Indicates the light distribution shape. Narrow angles concentrate light, while wide beams spread illumination.
- Color Rendering Index (CRI): Measures accurate color display on a 1–100 scale. Incandescents rate 100. Above 80 gives good color rendering.
- Color Temperature: Measures warmness or coolness on the Kelvin (K) scale. Lower numbers, around 2,700K, are warm yellow. Around 5,000K is cool daylight.
For task or accent lighting, choose bulbs suited to your needs. Evaluate color, spread, and CRI along with lumens. You can learn more about bulb brightness from ENERGY STAR.
Many LED and CFL bulbs now work with smart systems. Features like wireless controls, voice activation, scheduling, dimming, and automatic color temperature adjustment are available.
Smart bulbs cost $15 to $60, depending on features. Basic smart bulbs connect to WiFi and can be controlled from phones. More advanced options add voice control, brightness settings, automation based on time or activity, and integration with other smart devices.
So, Is Understanding Watts vs Lumens Important?
Yes, understanding watts vs. lumens is very important for choosing the best light bulbs. Watts show power use rather than brightness. Don’t rely on watts alone when buying bulbs. Lumens measure perceivable output. Use lumens to shop for the necessary brightness. Lumens per watt measure efficiency. Check this specification to find the most efficient bulbs. Use ENERGY STAR to find efficient CFL and LED replacement bulbs. Knowing the difference makes easy work of shopping for bulbs that maximize efficiency and suit your needs.
FAQs About Watts and Lumens
Are lumens the same as watts?
No. Lumens measure output, and watts measure power consumption. Lumens show brightness — watts alone do not.
Do all LED bulbs have high lumens per watt?
No. Early LEDs were inefficient, but the technology has improved. Check ratings to confirm efficiency. Quality LEDs achieve 80 to 100-plus lumens per watt.
Can I use any LED or CFL in a fixture made for incandescents?
Sometimes. Check for compatible bulb shapes and bases, and if necessary, make sure the bulb is rated for enclosed fixtures. Buy bulbs designed as direct replacements.
Why are my CFL bulbs burning out quickly?
CFLs last the longest when left on for over 15 minutes. Frequent on/off cycling dramatically shortens life. Make sure bulbs suit the usage. Also, choose name-brand bulbs for better longevity.
Why do my LED bulbs flicker?
LEDs are sensitive to voltage fluctuations that can cause flickering. This issue is common with dimmers not made for LEDs. Use compatible dimmers or install LED bulbs on circuits without dimmers.