Open refrigerated display cases are a staple of grocery retail. They encourage impulse buying, improve product visibility, and support fast shopper access. However, this openness comes with a trade-off. Without a physical barrier, these cases rely almost entirely on air curtains to separate cold internal air from the warmer store environment.

When air curtains are poorly optimized, warm air infiltration increases, temperatures fluctuate, and food quality suffers. Adjusting air curtain parameters can improve temperature stability, reduce energy use, and help extend product shelf life, directly helping retailers reduce food waste in open display cases. Maintaining the right humidity levels also plays an important role in preserving freshness, especially for produce and other moisture-sensitive products.

How Air Infiltration Drives Cooling Load

Air infiltration occurs when warm ambient store air enters the open face of a refrigerated display case and displaces the conditioned cold air inside. Because open cases do not have doors, they rely on air curtains in open refrigerated cases to create a protective barrier between the chilled cabinet environment and the surrounding store air.

When this barrier is disrupted, warmer air mixes with the cold air inside the case. The refrigeration system must then remove this extra heat to maintain the correct temperature, increasing the cooling load.

Several factors influence infiltration rates:

• Air curtain jet velocity and discharge angle, which determine how effectively the airflow forms a stable protective barrier
• Turbulence caused by shopper movement, which can disturb the air curtain and allow warm air to enter the case
• Store ambient temperature and humidity levels, which increase the heat and moisture load entering the display
• Case geometry and shelf configuration, which influence airflow patterns and how the air curtain behaves

The diagram below illustrates how ambient air enters the open case and interacts with the protective air curtain.

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Infiltration is one of the largest contributors to cooling load in open refrigerated cases, often exceeding losses from conduction through cabinet walls. As infiltration increases, refrigeration systems work harder, energy costs rise, and products experience temperature swings that quietly shorten shelf life.

Research Results on Energy Use in Open Refrigerated Cases

Optimizing airflow performance of air curtains in open refrigerated cases can lead to measurable reductions in energy consumption. Because open display cases continuously interact with the surrounding store environment, even small improvements in airflow stability can significantly influence refrigeration efficiency.

Research findings highlight that:

• Improved air curtain sealing reduces warm air entrainment, helping maintain a more stable barrier between ambient store air and refrigerated air inside the case.
• Lower infiltration translates directly into reduced compressor runtime, allowing refrigeration systems to operate more efficiently.
• Even modest airflow adjustments can reduce infiltration and improve overall refrigeration efficiency.

For example, a study examining airflow behavior in open refrigerated display cases found that optimized air curtains significantly reduced cooling demand by limiting the mixing between ambient air and refrigerated air.

Similarly, national laboratory research evaluating supermarket refrigeration systems concluded that airflow management strategies, including air curtain optimization, are among the most cost-effective energy-reduction measures available for open display cases.

Impact on Temperature Uniformity Across Display Shelves

Beyond energy use, airflow behavior inside display cases strongly affects temperature uniformity.

Uneven air distribution can create:

• Warm zones near the case opening
• Cold spots near the evaporator outlet
• Vertical temperature gradients across shelves

Computational and experimental studies show that poorly performing air curtains allow turbulence to penetrate deeper into the case, disrupting internal circulation. Optimized air curtains, by contrast, help maintain a more stable cold air envelope, improving temperature consistency from top to bottom shelf levels.

Links Between Temperature Stability, Food Safety, and Shelf Life

Temperature fluctuations are one of the hidden drivers of food spoilage in open display cases. Even short periods of exposure to warmer air can accelerate product degradation. Warmer temperatures accelerate respiration and moisture loss in fresh produce and promote microbial growth in packaged foods.

Because air curtains in open refrigerated cases help maintain a consistent cold environment, improving airflow stability plays an important role in protecting product quality.

Better temperature control helps support:

• Slower dehydration and moisture loss, helping fresh produce retain weight, texture, and freshness
• Lower microbial growth risk, as stable refrigeration conditions reduce repeated warming cycles
• Better visual appearance and texture retention, keeping products more appealing to shoppers

When temperature stability improves, retailers often experience lower shrinkage, fewer markdowns, and less product waste. In this way, air curtain optimization functions as both a food-quality intervention and an energy-efficiency measure.

Integration With Night Covers for Maximum Impact

Air curtains are most effective when combined with complementary strategies. One of the most widely used solutions is the addition of night covers, which provide a physical barrier over open refrigerated cases during non-operating hours. By covering the open case, night covers significantly reduce heat gain and moisture exchange from the surrounding store environment.

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Not all night covers are equal in quality. Prodew offers night covers that:

• Are aluminum coated for better insulation and won’t chip or fray
• Have a slow-rise mechanism with no oil
• Offer an easy screw or magnetic installation
• Include a unique, rounded, unbreakable handle
• Are composed of a perforated fabric that prevents condensation
• Come in a range of lengths and cassette options

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Laboratory evaluations show that when night covers are deployed, infiltration is almost entirely eliminated. As a result, refrigeration systems cycle less frequently overnight while product temperatures remain within safe ranges for longer periods. When paired with properly optimized air curtains, night covers enhance both energy savings and food preservation, creating a compounding effect that improves operational efficiency while helping retailers reduce product waste.

From Airflow Control to Fresher Displays With Prodew

Open refrigerated cases will remain a central feature of food retail, but their efficiency and effectiveness depend heavily on airflow performance. By fine-tuning air curtain parameters and integrating night covers, retailers can address food waste at its source while preserving product quality and lowering operational costs.

Properly functioning air curtains in open refrigerated cases also help carry humidity evenly throughout the case, supporting a more consistent environment for fresh products. Together, these improvements make air curtain optimization a practical step for improving both sustainability and profitability in refrigerated retail environments.

Retailers looking to strengthen freshness and reduce shrinkage in open refrigerated cases can learn how Prodew’s humidity and misting solutions support product quality and help protect perishables in airflow-exposed displays.

Contact us to learn more about how Prodew’s solutions can support freshness and efficiency in your refrigerated displays.

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