When ambient store air enters open refrigerated cases—especially during non-operating hours—it introduces warm, moist air into a cold environment, driving up energy use and accelerating product degradation.
But can you quantify that infiltration loss in kilowatt-hours (kWh)? And more importantly, can night covers act as a simple yet effective passive solution?
What Is Air Infiltration?
Air infiltration occurs when warmer, more humid air from the store environment enters open refrigerated display cases. This can happen continuously throughout the day—but it’s especially problematic at night when:
- No shopping activity is happening.
- No product is being accessed.
- Energy should be conserved—not wasted.
Key issue:-
Even when a case is “off-limits,” cold air is still spilling out, and warm air is moving in, forcing compressors to work harder to maintain temperature setpoints.
Can It Be Measured in kWh?
Yes—and it has been.
According to research published by Lawrence Berkeley National Laboratory (LBNL), infiltration can account for 50% or more of total energy consumption in open refrigerated cases.
In controlled studies, night covers have been shown to reduce this infiltration significantly.
Energy Impact Findings:
Open multi-deck cases: Lose up to 1.3–1.8 kWh per foot per night due to infiltration alone.
Adding night covers: Can reduce that loss by up to 75%, saving 0.9–1.4 kWh per foot per night depending on conditions.
Let’s translate this:
> A typical 12-foot open dairy case without covers could lose up to 20 kWh every night. At $0.12 per kWh, that’s $2.40 per night, or nearly $900 per year—per case!
Night Covers as Passive Thermal Barriers
Night covers, like those from Econofrost, serve as a passive, non-mechanical thermal barrier. They reduce energy loss without requiring any power, installation overhaul, or operational training.
How They Work:
- Aluminum fabric reflects heat and blocks radiant energy.
- Tight sealing prevents warm ambient air from entering the refrigerated air curtain.
- Condensation is minimized, reducing defrost cycles and microbial risks.
Unlike sliding doors or automated systems, night covers require no electricity and introduce no mechanical noise, complexity, or maintenance.
Thermal Benefits Backed by Science
Research from the University of Wisconsin’s energy management lab and U.S. DOE case studies found that night covers reduced case infiltration rates by 60–80%, depending on humidity and store design.
Key Findings:
- Lower average case temperatures overnight.
- Fewer compressor cycles.
- Improved temperature recovery in the morning.
Retailers also reported fewer temperature alarms and better product condition in the morning, especially for sensitive items like dairy, leafy greens, and pre-cut produce.
Energy, Cost & Sustainability Impact
Adding night covers to existing open cases is one of the fastest-return energy efficiency upgrades available to food retailers.
Typical Savings:
| Case Type | kWh Saved per Year (per 12-ft) | Annual Savings (@ $0.12/kWh) |
|---|---|---|
| Dairy Case | 3,500 – 4,800 kWh | $420 – $576 |
| Produce | 4,000 – 5,600 kWh | $480 – $672 |
| Meat/Seafood Case | 5,200 – 6,800 kWh | $624 – $816 |
These savings multiply across dozens—or hundreds—of cases per store, making night covers not just an efficiency tool but a sustainability asset.
Integration and ROI
Econofrost night covers can be retrofitted into most open multi-deck cases without complex modification.
Installation Highlights:
- Tool-free or low-tool setup.
- Available in manual or motorized (auto-retractable) models.
- Compact housing and low visual impact.
- Durable woven aluminum or blackout fabric options.
Return on investment is typically under 2 years—and often less than 1 year with utility rebates.
What Retailers Are Saying
“We used thermal imaging to compare cases with and without covers. The temperature retention difference was immediate—and our compressors weren’t cycling as frequently.”
- Refrigeration Manager, Western U.S. Grocery Chain
- “Econofrost covers paid for themselves in under 9 months. They’ve become a standard part of all new store builds.”
- Sustainability Officer, National Retailer
Footnotes and References
- Lawrence Berkeley National Laboratory (LBNL): Studies on infiltration losses and refrigeration system efficiency in open refrigerated cases.
- U.S. Department of Energy (DOE): Refrigeration energy efficiency guide—night covers and infiltration mitigation.
- University of Wisconsin-Madison Energy Center: Thermal impact testing on infiltration barriers for open refrigerated cases.
- Econofrost Product Data & Case Studies: Field results from multi-store rollout of night covers, compiled in Promolux/Econofrost technical archive (2023).
Final Thoughts
Air infiltration may be invisible—but its energy cost isn’t. If you’re looking to reduce refrigeration load, stabilize case temperatures, and hit your energy efficiency goals, night covers are a simple, powerful tool.
- Easy to install
- Proven to reduce infiltration loss
- Pays for itself in under 2 years
- Improves product quality and case performance
Learn more about integrating night covers into your store’s energy strategy: www.energy-savings-refrigeration.com
