Lumens, typically abbreviated as lm, are units of measurement specifying the total quantity of visible light emitted by a lamp or light source. Essentially, this metric indicates how bright a light source is.
A greater lumen count means that the light is brighter, while a lower lumen count signifies that the light is dull. The number of lumens you need has a lot to do with how the light is used.
When purchasing a flashlight, a suitable bulb for your living room or even a camera, you should consider lumens.
Table of Contents
- What is a Lumen?
- How Many Lumens Do You Need?
- How to Read a Light Bulb Label
- How to Choose Energy-Efficient Light Bulbs
What is a Lumen?
A lumen is the International Unit of luminous flux. It is the quantity of light emitted per second by a source of one candela (candlepower) in a unit solid angle of one steradian.
In layman’s terms, it is a unit of brightness. Traditionally, we measured the brightness of a light by its wattage.
However, this unit was inaccurate since wattage is simply a measurement of the energy a bulb consumes when switched on at any given time.
Lumens vs. Watts
Lumens and watts do not measure the same thing. Watts are units of measurement for how much energy a light bulb uses to produce light, whereas lumens are units of measurement for how bright a light bulb is.
With many light bulbs available today, evaluating brightness using wattage is difficult. Instead, lumens more accurately define a light bulb’s output than watts.
In the past, the number of watts indicated the brightness of an incandescent bulb. A 100W bulb would be regarded as brighter than a 60W light.
Light bulbs using watts are being phased out due to the increase in more energy-efficient technologies. Modern gadgets are being developed to produce the same lumens while using less power.
How Many Lumens Do You Need?
When it comes to how many lumens you should use if you want to replace a light bulb, the chart below shows how many lumens your specific bulb produces.
Keep in mind that it’s not always as black and white as simply converting from watts to lumens. You’ll also want to consider how you plan to use your light in order to determine exactly how many lumens would be ideal for your space and needs.
How to Read a Light Bulb Label
As of January 2012, the Federal Trade Commission implemented a mandate for all manufacturers to include lighting facts labels on all bulbs.
Just like a label listing nutritional facts helps you pick the right food for you, manufacturers place a label on the bulb package to assist you in selecting the appropriate light for your application.
The label indicates the brightness, appearance, energy consumption, longevity and annual use cost of the bulb.
Lighting Facts Label of an LED Bulb, equivalent to a 60 W incandescent bulb
Brightness is an indicator of how much light a bulb produces. In this case, the brightness is measured in lumens. The more lumens a light bulb has, the brighter it is.
Estimated Yearly Cost
This is how much it will cost you to use a bulb every year. The dollar count estimates how much you will spend based on three hours of daily use and a rate of $0.11 per kWh (kilowatt per hour).
However, this figure may vary based on three variables.
- Electricity rates
If your bulb has a higher wattage, it consumes more energy to produce electricity. In turn, this costs you more money.
Plus, if you leave the bulb on for more than three hours daily, the cost will also increase.
Additionally, electricity rates vary by area. Make sure to check with your power supplier to see how much per kWh they charge.
Every bulb has a set lifespan. Manufacturers include this on the bulb packaging.
The label specifies the bulb’s lifespan in years or hours. This number represents how long one bulb will last if you just use it for three hours per day.
Depending on how much or how little you use the bulb, its lifespan could vary from what is on the label.
It’s important to note that LED bulbs do not burn out like incandescent bulbs. Instead, they start to dim. An LED bulb is still functional until it loses 30% of its brightness.
Light appearance is the color of light. It does not represent brightness but rather its hue.
In Kelvin (K), color temperature is frequently used to determine light color. Warm yellowish bulbs have a color temperature of 2,700 K to 3,000 K.
These produce light similar to incandescent bulbs. As the color temperature rises, the color becomes cool and whiter. If the scale pointer is between 3,500 K and 4,100 K, the bulb should give off a cool white light.
Color temperatures of 5,000 K and above have a bluish hue that resembles daylight.
When selecting a bulb, you should take color temperature into account, depending on the intended purpose and the mood you’d like to create.
As much as we’re using lumens to identify brightness now, we still need watts to show a bulb’s electricity consumption. A bulb’s wattage has a direct impact on monthly electricity bills.
If you know how many watts your incandescent bulb uses, compare an LED with the same lumens using the chart interpretation. As you will notice, the wattage on the latter will be much smaller.
The lower the wattage, the cheaper your electricity bill will be.
How to Choose Energy-Efficient Light Bulbs
Switching to energy-efficient bulbs saves money in two ways. This includes monthly utility bills and replacement costs.
The U.S. Department of Energy estimates that lighting accounts for 15% of the average home’s electricity use. It also reports that LED lighting saves the average household $225 in energy costs each year.
Energy-efficient lighting can provide the same amount of light for less money. In terms of energy efficiency, LEDs are superior.
However, LEDs are also the most expensive type of light. Compact Fluorescent Lamps (CFLs) and halogens are less expensive options.
Look for an ENERGY STAR® Label
The word “energy-saving” can be overly broad and vague. Not all energy-saving products meet the exact requirements to be an ENERGY STAR® product.
You’ve probably seen this label while shopping for electronics, appliances or light bulbs. It’s a blue label printed in white with a star on it.
To receive the ENERGY STAR® certification, a product’s energy usage and performance are evaluated and certified in a laboratory. Both CFLs and LEDs can qualify for this label.
Certified bulbs use two-thirds less energy and last 25 times longer than incandescent equivalents. Besides being energy efficient, bulbs must also meet the needs of consumers.
ENERGY STAR® bulbs are available in various shapes and sizes, including pendant lights, track lighting, integrated downlights and more.
An ENERGY STAR® bulb might cost more initially, but it will save you money in the long run.
Consider LED lights when shopping for a new light bulb for your home. You’ll save money on your energy bills and cut your carbon footprint.
The Department of Energy established new guidelines under Biden’s administration that will lead to the phase-out of incandescent bulbs and the adoption of energy-efficient alternatives.
Under the new requirements, any bulb must output at least 45 lumens for every watt of power used. Traditional bulbs are unlikely to meet this demand, as 60-watt bulbs only produce 14 lumens per watt.
Incandescents are inefficient because only a tiny percentage of the electricity is used for lighting, with the rest being lost as heat. While incandescent bulbs are still accessible in retailers, they are no longer manufactured or imported into the United States.
Traditional light bulbs will be replaced by LED and CFL bulbs over time. By July 2023, there will be no more incandescent bulbs in use.
Check the Color Temperature
New energy-saving lights display color temperature as a scale. Temperature is expressed in Kelvins (K). When buyers turn it on, it displays the appearance of the bulb inside. Color temperatures in ‘cool’ colors are higher and lower in ‘warm’ colors.
People are sometimes hesitant to switch to energy-saving bulbs because they are concerned about the difference in color temperature between these lights and standard incandescent bulbs.
CFLs and LEDs are now available in various colors ranging from warm white to cool white to daylight. Choose an equivalent LED that ranges from 2,700K to 3,000K if you want a warm golden tint like traditional bulbs.
Color is frequently used in living rooms and bedrooms to create a relaxing atmosphere. A colder white hue has a color temperature between 3,100K and 4,500K.
This series is frequently used in task areas to create a focused environment. People also use them to improve their kitchen or bathroom vision.
Bulbs with a color temperature of 5,000K or higher have a bluish hue, similar to daylight. These bulbs emit a lot of light and are frequently used for outdoor lighting.
You can change the color temperature of your light using a smartphone app with smart LED bulbs.
Evaluate Lumens, Not Watts
Lumens are a precise measurement of the brightness of a light source. Watts are only used to calculate how much energy is consumed. With energy-saving bulbs, wattage no longer equates to brightness.
As LED lighting becomes the norm, it’s critical to understand how many lumens your space requires. Although wattage is still important from cost-savings and eco-friendly perspectives, LEDs are designed to use as little as possible. As a result, wattage is becoming obsolete.
It is more important to understand how many lumens you require so that you do not end up with a bulb that is either too bright or too dim. Since LEDs produce more lumens than incandescent lights, they may reduce the number of light sources required in a room.
A lumen is a unit of light output that can be directly measured, regardless of whether it is produced by an incandescent, halogen or LED bulb.
One lighting manufacturer may develop a 12-watt LED bulb to replace a 60-watt incandescent. Another manufacturer may release a nine-watt LED with the same number of lumens.
As a result, it is preferable to consider light bulbs in terms of lumens.
Look at the Color Rendering Index (CRI)
The Color Rendering Index (CRI) measures how a light source illuminates an object. It is evaluated by comparing it with a reference light source. Natural light (daylight) with a CRI of 100 is frequently used as the reference source.
We need an object to appear as it would in natural light when using an artificial light source. The index ranges from 0 to 100, with 100 indicating that colors appear as they would in natural light.
The CRI of good light sources ranges from 80 to 90. A CRI above that is suited for areas where color accuracy is critical.
Incandescent and halogen lamps have color rendering indices close to 100, while LEDs and fluorescents have values between 60 and 90.
Lumens are the most precise measure of brightness available today and are an excellent way to determine how many light fixtures you’ll need for your home. The use of watts as a measure of brightness is no longer accurate.
Remember that the lower the wattage, the more efficient the light bulb.
Low-energy light bulbs are quickly taking over the market. Picking the best energy-efficient bulb for your needs should be a breeze now that you’re familiar with the terms on a light bulb label.
Best of all, there are no restrictions when it comes to selecting the ideal bulb. It all comes down to personal preference and the space you’re trying to illuminate.