Energy Savings

Save money with an HVAC economizer

If you have a large home, business or other large space that you have to cool you may want to consider getting an HVAC economizer.

Dry, cool weather is most optimal for these devices -preferably hot during the day and cool at night. Here in Illinois we get a little bit of all the seasons, so while an economizer can be effective here there are times where the air conditioner will have to work harder to cool.

However, in the right climate these devices can save big bucks with a process known as ‘free cooling’.

What is Free Cooling?

Free cooling is act of pulling cooler outdoor air inside without relying on the an air conditioner to cool the air.
The unit pulls in air that is below the desired temperature with a lower humidity by using logic controllers and outdoor sensors -so if the air outside is ‘better’ it knows to whether or not and how much air to pull in using the dampers. On the other hand, if the air outside is hot enough that it’s not beneficial to the system then the system is closed off and switches to mechanical cooling.  These systems measure these conditions using enthalpy, which is kind of like a measurement in thermodynamics that determines the total heat content along with pressure and volume.

Comparison of the different types of hvac economizers

  • Dry Bulb: These are cheaper to install and maintain but aren’t necessarily the best option as they only detect temperature.
  • Wet Bulb: Also known as a single enthalpy, detects the energy in the air to determine how humid and hot the air is outside.
  • Differential Economizer: Differential enthalpy makes use of an outdoor sensor and one on the return air to determine the difference.


Overall this process puts less strain on the the air conditioning. This also shortens the duration it needs to run to meet the set temperature / humidity level.

As you can imagine this can really cool large spaces down at significant savings.

How significant are the savings?

Reduce Mechanical cooling by as much as 75%

These systems even may come built into rooftop cooling systems as they are known to have such a strong effect of pulling in cool air while minimizing the use of actual air conditioning significantly.

If you are unsure of your system, are interested in improving your hvac system, or just feel like there is room for improvement in efficiency don’t hesitate to call our hvac experts!