Q: I own a convenience store, so a lot of my electric bill is for my coolers. I’ve been hearing that there’s a way to bring outside air into a cooler during the winter to use less electricity. What can you tell me about this? How much can this save me? Any and all information appreciated. - GL, Lamoille County
A:
Paul: What you’ve been hearing about is called an outside-air economizer, for walk-in coolers. It’s worth investigating for a store like yours, or for any business that relies on a walk-in cooler, such as a restaurant, grocery store, or beverage center. This equipment automatically brings outside air into a walk-in when outdoor temperatures fall below the cooler’s required temperature. Using the colder outside air instead of the walk-in’s compressor, condensing unit, and evaporator fans saves energy and money.
Dan: Economizers are best in coolers where you store closed or packaged products, such as beverages, because the outdoor air could make exposed food dry. This technology can be particularly useful in a climate like ours. Vermont temperatures are cool enough for about 120 days per year to allow us to make good use of economizers. Savings can be in the $275 to $770 range each year, depending on factors like your cooler size and your store’s operating hours. You can save even more if you have an evaporator fan motor control installed with the economizer, because it will shut down some of the evaporator fans when the compressor isn’t running.
Paul:Typically, for an economizer to be cost effective, the volume of a walk-in cooler needs to be at least 1,000 cubic feet (that’s volume ─ not square footage). However, other factors must be considered to optimize your investment, so it’s best to talk to a contractor who installs this equipment to determine if this is a good financial move for you. Economizer manufacturers will either do the installation or refer you to a list of qualified contractors in your area. If you need help finding manufacturers working with Vermont businesses, give Efficiency Vermont a call, toll-free: 888-921-5990.
Dan: To install an economizer, a trained contractor will mount air-intake and exhaust equipment through the walk-in cooler room’s exterior wall as well as a control unit and efficient circulation fan(s), which will operate when evaporator fans are off. Typically, manufacturer-approved installers can also maintain and repair these systems.
Paul: Efficiency Vermont offers financial incentives for economizers used in walk-in coolers with a volume of 1,000 cubic feet or more. Rebates are also available for other energy-saving refrigeration equipment and for efficient boilers, furnaces, ventilation, air conditioning, and lighting. You can download easy-to-use, mail-in rebate forms at EfficiencyVermont.com. Additional rebates may be available for custom projects, so contact Efficiency Vermont if you don’t see certain equipment listed.