Small Box Retail: Think Outside the Energy Box

Overview

This opinion column by Martin Flusberg, chief executive of controls maker Powerhouse Dynamics, appeared on Energy Manager Today on April 16, 2014. It asks why energy management systems (EMS), standard in big-box stores, had barely reached small-box retail, defined here as stores under 10,000 square feet, and what had begun to change. The piece is short, about three printed pages, and written for retail facilities and energy managers rather than engineers.

Key Findings

• Three structural reasons kept small stores out of the EMS market: their energy spend is small, so absolute savings look modest; many sit in malls or strip centers where the landlord owns the HVAC and bills by square footage; and a small box was assumed to be too simple to optimize.
• Early EMS offerings for small retail were scaled-down versions of expensive big-box systems, so the payback rarely worked.
• Flusberg's "EMS 2.0" combines internet-connected thermostats, cloud software, low-cost wireless sensors, and equipment diagnostics, cutting deployment cost enough to make multi-site small-format chains viable.
• In a typical store the two dominant loads are HVAC (mostly cooling) and lighting, and lighting can reach 40% of total energy. Lights left on after closing, or exterior lights burning in daytime, are the low-hanging fruit.
• Even simple sites can do demand limiting by cycling rooftop units; the author says it works with as few as three RTUs, which is easier than in restaurants with mixed kitchen and dining loads.
• Citing an Ecova report, retailers as a sector had cut energy use 12% since 2008, more than any other vertical, and big-box chains such as Best Buy and Walmart were opening much smaller stores that would need cheaper controls.

Why It Matters for Daylighting

If lighting is up to 40% of a small store's load, the cheapest kilowatt-hour is the one daylight replaces. Single-story strip-center and freestanding retail is well suited to prismatic skylights, which spread diffuse light across the sales floor without the hot spots and glare of clear domes, and the daylight-responsive dimming they call for is exactly the kind of low-cost, cloud-connected control this column describes. Pairing toplighting with an EMS 2.0 platform lets a chain verify the savings remotely, benchmark stores against one another, and catch a failed sensor before it costs a month of savings.

The column also flags the landlord problem: where the tenant does not own the roof or the HVAC, skylights and controls have to be negotiated into the lease or the base building. Retailers building new small-format stores, however, control the design and can bring the lighting load down before the meter is ever set.

About the Source

Energy Manager Today was a daily trade site for corporate energy and facilities managers, later merged into Environment + Energy Leader. The column was written by Martin Flusberg, CEO of Powerhouse Dynamics, and published April 16, 2014; the library copy runs three pages. Energy Manager Today's original page is no longer online, but the author's company republished the column in full on its own blog a few days later, and that version is linked here.