Why do you need cooling?
Removing the heat from the LEDs extends the life of the product. Think of an LED light installed inside a cooler or freezer area. The ambient air is cold. The entire air source of the cooler area acts as a heat sink, keeping the LEDs performing extremely well and efficient for years. And while it is impractical to only install LEDs inside a cool environment, having a heat sink to remove this heat is the next best thing.Removing Heat: Active Cooling
So what is active cooling? Typically, this means fan. This type of cooling has been used for decades on other types of electronics: computers, laptops, TV's and amplifiers. Fan's blow a steady stream of air onto a a heat sink and transfers the air away. If inside an enclosed fixture, this hot air is then moved to the fixture itself, thus acting as a secondary larger heat sink. It creates airflow inside the enclosed fixture, creating turbulence over the face of the LED's, removing any static heat that might built up that might build up without the present airflow.
Within the LED industry, there had been a debate on whether fans are good or not. Some who think they are bad claim they are a point of failure. And over the years, we have heard these types of arguments as well. However, the truth of the matter are fans are extremely robust and rarely fails. MyLEDLightingGuide has sold 1000's of active fan retrofit kits over the past 10 years, and have maybe seen 2 failures. In both cases, water intrusion into the fixture caused the fans to fail.
The benefit to an active fan solution is the physical size of the heat sink required is significantly smaller. So retrofitting an existing fixture, replacing the bulb and ballast with a LED Conversion and Replacement Kit, makes sense. Without the active fan, the heat sink would be too large to fit into the existing fixture.
Removing Heat: Passive Cooling
So why not use a fan all the time? Well, you don't need to. Lighting designers can integrate the heat-sink as the fixture housing, combining both form with function. Take our LED UFO High Bays. The UFO part of the fixture is the heat sink. It is significantly large enough to absorb the heat produced by the LEDs, and radiate the heat away from the fixture. These types of fixtures are typically not installed inside other fixtures, so it can utilize what ever available air flow is available to help remove air that is available. Outdoors, there are available breezes that can effectively remove heat. So creating a stylish fixture that radiates heat away is practical and economical. Engineers can easily design the right size heat sink to accommodate the removal of heat for the fixture they are designing.
So What Better?
Neither. They are both good. Both are perfect for the solution they were designed to solve. Fans are extremely robust. So you should not let the fan, if a retrofit is your best option, be the deciding factor on moving forward with either an active cooling or passive cooling solution.