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Energy Efficiency and Night Blinds

Published: July 1, 2021

Many retailers of fresh food and drinks understand that the use of a night blind will reduce energy consumption on an open front refrigerated cabinet left running during non-retail hours.

Intuitively that sounds right. But how significant are the energy savings? Our Mechanical Engineer, Steffan Morrison wanted to know.

Steffan asked our refrigeration engineer for test data for the FPG Visair Slimline refrigerated open front cabinet, comparing energy usage with the night-blind down, and with the night blind up1.

Photo 1: FPG Visair Slimline cabinet in testing with night curtain up. Photo 2: FPG Visair Slimline cabinet in testing with night curtain down.

Table One provides a summary.

Table One: FPG Visair Slimline 1800 Energy Consumption: Night Blind Down versus Night Blind Up

– Night Blind DownNight Blind UpDifference
Average Energy Usage [kWh/h]1.551462.447860.8964
24 Hr Energy Usage [kWh/24h]37.235158.748721.5136
Max Amps [Amps]13.89513.941

The energy savings are significant. If we assume the night blind is used 12 hours per 24 hours, it amounts to more than 3,900 kWh per year per cabinet. Calculate that over an appliance fleet and you are talking big numbers. A great outcome for reducing demand for energy, especially in the scenario where that energy is generated from fossil fuel sources.

There are financial benefits too. Steffan applied the following assumptions:

  • Over 24 hours, the blind is up 12 hours and then down 12 hours
  • Power rates vary significantly around the world. Steffan used a New Zealand rate of 29.11c per kWh

Table Two: Financial Impact (NZD) of using a Night Blind

– Night Blind DownNight Blind UpDifference
12 Hr Energy Usage [kWh/24h]18.6175229.3743210.7568
Cost for 12 hours$5.42$8.55$3.13

Calculate the saving of $3.13 over 365 days and that’s a savings of $1,142 per cabinet per year.

If you operate a fleet of cabinets, that certainly adds up to a significant amount per annum and over the life of the cabinets.

It’s also worth noting that the principle applies to cabinets with integral refrigeration as well as cabinets connected to remote refrigeration.

If your business wants the benefit of increased revenue from open front refrigerated cabinets and needs to run the cabinets out of open hours, then it makes sense to request a night blind. The small act of pulling it down at store closing is not only good for the environment, it also makes good business sense.

FPG now designs many of its open front cabinets to accommodate a night blind so that they can be easily retrofitted while in situ. However, we recommend that you request it when ordering the cabinet and establish operational best practice from day one.


1Energy consumption required to deliver +2° – +4°C average core product temperature for climate class 3 using R449A integral refrigeration.

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