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Cooling For (Nearly) Free?! It’s Possible with an Economizer

Wednesday, February 25, 2015
Rooftop Unit

Free cooling in your facility sounds too good to be true, right?  Well, economizing may not be free, but it is certainly less expensive than mechanical cooling.  During what are referred to as the “shoulder months” for cooling, when energy demands are the lowest – March, April, May, September, and October -- a commercial building with a properly operating economizer feature installed on its RTUs (Roof Top Units) can stay cool without running any mechanical air conditioners. 

How does it work?  
Think of the economizer on your system as the equivalent of opening a window in your home and sticking a box fan in front of it. An HVAC system with an economizer will open an outside air damper and run the system fan, while simultaneously reducing the amount of return air by exhausting it out of the RTU.  A fully functioning economizer has a control board that is dialed in and programmed to actuate based on outside air temperature and the need for cooling inside of the building.  Depending on the capabilities of your control system, the economizer can be programmed to bring in “free cooling” at outdoor temperatures as high as 58 degrees.  If it is 74 degrees in your work space, the thermostat is set to 71, and the outdoor temperature is under 58, your system’s economizer should open and provide cool outside air.  In addition to saving energy, economizers also reduce potentially harmful wear and tear on compressors that comes from running during low outside air temperatures. 

Translating economizer use to dollars and cents 
A typical 30,000 square-foot office building costs an average of $8.50 per hour to condition the entire space. Cooling the same building using economizers costs, on average, only $1.85 per hour!

Maintenance is key
Economizers are mechanical in nature and should be inspected and maintained regularly.  Linkages often require lubrication and motors should be inspected to ensure they are functioning.  Washable filters over the economizers should be cleaned annually to allow for necessary air flow.  Your Ahern service technicians take care of these needs for you during their diagnostic inspections and maintenance with a planned maintenance agreement (PMA). 

If you are currently not using Ahern for your HVAC service provider and you are interested in having your heating and cooling system inspected for proper operations, please contact us! A local sales representative will be happy to discuss our HVAC service as well as other offerings we provide.

Other articles that might interest you:

Exhausting Your Energy Savings

A Plug on Filters

HVAC: If It Isn’t Broken…Fix It?

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