Lighting candles can be aesthetically pleasing. But when it comes to relying on them as a light source, you might be disappointed.
The average candle generates a little over 12 lumens. This is not much considering how a standard light bulb produces 450 lumens. You’d need over three dozen candles to produce as much light.
Keep reading to learn more about what you can expect from a candle’s light power and the best times to use the gentler light they produce.
What’s a Lumen and How Does it Affect Me?
A lumen is modern terminology used to describe a unit in the international system of measurement used to calculate artificial light. It represents the amount of light that angles out into space from one point.
Understanding Light Quality
Light quality is a highly involved topic, and I won’t pretend to be an expert. I didn’t fully consider the impact that light quality has in our day-to-day life until I came across the Illuminating Engineering Society (IES).
They created a light quality Venn diagram that illustrates intersection between:
- Human needs
- Architectural/site-related issues
- Economics, energy-efficiency, and the environment
For humans, proper lighting affects visibility, safety, ability to carry out tasks, mood, communication, visual comfort, and more. How structures are built help determine the amount of natural light we’re exposed to, the style of lighting we encounter indoors, how we can safely use artificial lighting with the proper codes in place, and so forth. Correct installation and maintenance along with efficient energy use are additional overlapping factors.
So how does candle light fit into all of this? Well candlelight creates a certain mood of rest and relaxation. It’s less intense than other forms of light, and there might be more safety precautions to consider.
As IES indicates, all lighting requires safety but electrical lighting, for instance, is safer to use because we aren’t exposed to the light filament the way that we can come in direct contact with a candle flame. Electrical lighting also has to meet local, state, and federal safety codes when installed in a building or other structure, like a house.
Light quality has a huge impact on your daily life. So it can help to understand how light intensity that’s produced by a candle might change your mood, safety, behaviors, or ability to carry out certain activities.
Sometimes we rely on candles to help us navigate through the house after a power outage. In this way, the light helps keep us safe because we can avoid tripping over objects we wouldn’t be able to see if it were completely dark.
How Many Lumens Does a Candle Produce?
Although candles can help us to see and engage in daily life activities if we lose access to other forms of light, it’s important to keep their usefulness in perspective.
Candlepower is an outdated term that describes “luminous intensity expressed in candelas.” One candela is one lumen per steradian (lm/sr). A steradian is also called a square radian. It’s used in three-dimensional geometry and describes the distance from the center of a sphere extended out to twice as much as its radius.
Imagine your lit candle floating inside a bubble. The amount of light that shines from the flame to the edge of the bubble is its radius. But the space that that light covers extends beyond that one point on the bubble’s surface. And the way that a portion of the light spreads out kinda looks like a slice of pie.
So you can think of the candle flame as the sharp point of a slice of pie. And then the wider angle that the pie forms can represent a portion of light generated by the flame. This is the steradian (square radian, r²). This space usually comes to about one square foot away from the candle.
I made a (scientifically inaccurate) diagram to help illustrate what happens.
Keep in mind that one steradian is just one “slice of the pie” so to speak. It’s only one portion of the amount of light generated by the flame. As IES explains, one steradian equals one lumen. The area inside our little bubble is 12.57 times the radius. That would be the same as 12.57 lumens. So one candle generates 12.57 lumens of power.
According to IES, “Light quality encompasses the appropriate use of light and darkness for human needs, achieving the optimum balance of practical and aesthetic issues of the built environment.”Illuminating Engineering Society
Do Candle Lumens Provide Enough Light Power?
When it comes to significant light output, candles don’t measure up. They provide us with some light for a short period of time, but they don’t produce enough light power to completely replace a lightbulb.
A standard lamp or light fixture requires at least a 40 watt light bulb. This wattage relates to a regular incandescent lightbulb. If using a halogen light bulb, its 40 watt equivalent would be 29 watts. An LED bulb equivalent would be 6 watts. All three of these bulbs – 40, 29, or 6 watts – have a brightness of 450 lumens.
If one candle generates brightness of about 12.57 lumens, then you would need more than 35 candles to generate enough light to replace a low wattage light bulb.
Lighting candles in an emergency situation can be helpful. You’ll be able to see at least one foot (12 inches) ahead of you. But candles are not a sustainable light source when considering the number of lumens they generate.
How Can I Best Use Candle Lumens?
Candles are not an ideal option for lighting large areas. Referring back to the IES definition of light quality, the most appropriate use of candle light seems to largely be reserved for aesthetic reasons in small to medium spaces.
The best places to use low lighting is usually the bathroom or bedroom. Warm lighting from a candle can create a spa experience in the bathroom. Depending on the size of your bathroom and the amount of light you’ll feel comfortable having, you might only need to light two or three candles.
In cases such as this, candles are in their element – especially of you’re using scented candles. Lighting candles in the bathroom can go beyond generating low light ambiance. Depending on the candle, you can create a relaxing aromatherapy treatment. They also provide some warmth, which can extend your bath time.
In bedrooms, it might be necessary to use candles as supplementary light. Otherwise, you’d probably need to light a dozen or so. This may or may not be appealing to you. Again, it depends on the size of the room and what you’re trying to achieve.
Lighting candles in the bedroom can be equally relaxing. You can read a book under warm blankets or have a night in with your partner. Just be sure to have a plan in place to avoid falling asleep with the candles lit.
If you’re creating a low key atmosphere throughout the home, feel free to light candles in the living room or kitchen as well. There really aren’t any hard core restrictions to using candles as a light source. (But please don’t core apples or peel carrots by candlelight. Ouch!)
More modern homes have open floor plans, so I’m sure you’ll make the best lighting choice based on the layout of your home.
Just be sure to never leave any lit candles unattended. Depending on how you’ll be using the light, sometimes it’s safer to turn on a low watt light bulb in order to support the subtle glow given off by candles.