Spotlight: Retail HVAC Fans

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Retail HVAC supply air fan fault

SiteSage discovered that the brand new Roof-Top Units (RTUs) at this retail store arrived with a manufacturers’ defect

A common source of HVAC energy waste is blower /supply fans running 24/7/365, including unoccupied and overnight periods where the supply air is definitely not required. SiteSage internet-connected thermostats allow you to set fan mode in AUTO or ON by time block, thus ensuring that fans only run when needed and capturing the associated savings. SiteSage data for HVAC units also helps identify a common but wasteful “trick” of HVAC techs: installing a mechanical “jumper” on the HVAC unit control board, which essentially overrides any fan commands from the thermostat and forces the fan to run 24/7.

SiteSage data alerted one of our retail customers to multiple Rooftop Units (RTUs) that had their fans running 24/7, and we all expected to find a series of jumpers installed. In fact, the problem was deeper than that. Due to a glitch or miscommunication at the factory, all of our customer’s newest RTUs came straight from the factory programmed to run fans 24/7! The chart here shows the day that one of these RTUs was fixed. Before 11am the fan runs constantly at 4000W (shown by the green line of energy usage), even at 2am when the store was closed! In the afternoon after the repair, then fan cycles off when not required to run. Assuming the fan ran 10 hours per day when it wasn’t needed, bringing it to normal operation saved over $1,400 per year for this unit alone. Across the entire fleet of newly purchased RTUs, that would have really added up to a lot of waste!

Learn more about saving energy costs in small-box retail stores: