Lumens is a measurement of light that a device produces. LED light bulbs can produce the same amount of lumens as incandescent light bulbs but with fewer watts. For example, a 9 watt LED light bulb can produce 800 lumens whereas an incandescent light bulb will need 60 watts to produce the same amount of lumens. As manufacturing standards have improved it is much easier to find LED light bulbs with higher lumen counts without spending a fortune.
Illuminance or LUX is the total amount of light that shines on a surface. Although similar, the difference between Lux and Lumens is that lumens measures the total amount of light emitted in all directions and lux measures the total amount of light that is concentrated on an area. For example, a light bulb that produces 1000 lumens over one square meter would mean that we have an illuminance of 1000 lux. However if the same 1000 lumens were spread out over 10 square meters we would only have an illuminance of 100 lux, therefore requiring the need for additional light bulbs to shine light on the desired area.
Another important factor in selecting LED light bulbs is to consider a light sources CRI or color rendering index. The Color Rendering Index (CRI) measures the ability of a light source to bring out the true colors of an object. Without a high CRI, objects can appear dull, faded, or washed-out. CRI is measured on a scale from 0 to 100 and the closer to 100 the better. A CRI rating of 85 or higher should be considered when purchasing any LED product.