Commercial reach-in coolers and freezers are usually fitted with door heaters to reduce fogging and condensation and allow products to be more visible to customers. When the glass doors become fogged, it becomes difficult for customers to see the products, so they'll open the door for longer periods to clear the fog. This can lead to increased air infiltration and subsequent energy wastage. Electric door heaters prevent the formation of fog and condensation.
How do electric door heaters work?
Fog and condensation are formed when the temperature outside the coolers is lower than the dew point of the air inside. The electric door heaters dry the air in and around the reach-in coolers and freezers enough so that the moisture does not condense. When the air is dry, there is no need to apply more heat; however, this is usually not the case in most commercial settings. Heat is continuously applied, even when it's not necessary.
There are a few measures you can take to save energy by ensuring that your reach-in coolers and freezers' door heaters remain turned on only when needed. They include the following:
- Install a humidistat on the door
A humidistat can be wired to the reach-in cooler or freezer to measure the relative humidity inside the store. The humidistat can be manually adjusted so that when the humidity level in the air reaches a certain level, the door heater is automatically turned off. When the humidity in the air rises above this user setting, the heater turns back on. You will find that the heater will most likely be turned off during most of the time, and this increases energy savings.
- Install an electric controller
Electric controllers are more efficient than humidistats in saving energy. They measure not only the relative humidity but also the temperature and dew point of the air. This function allows the controllers to release the exact amount of heat needed, unlike humidistats which turn on heaters on a standard setting. The heater can be on for short or long pulses depending on the amount of heat required to prevent condensation at a particular time.
- Invest in zero-energy doors
Zero energy reach-in cooler doors are fitted with layers of insulating film and thermal breaks in the frame so that they do not require any heaters to prevent condensation. Although they need upfront investment, they can significantly reduce the amount of energy used in preventing condensation.
Reducing the energy consumption of reach-in coolers and freezers can help in reducing the overall energy costs in your store. By following these tips, you can save money by ensuring that door heaters run only when heat is required to prevent fog and condensation.