Use a “night purge” to cool your building at night


Almost 10% of building electricity use is for air conditioning.  Setting your ventillation system to bring in cool night air, and pre-cool the building overnight can greatly reduce the need for air conditoning.


In the cooling season, set your ventillation fans to run for about two hours prior to staff arriving in the morning.  This should take advantage of the cool early morning air, and be enough time to cool the building.  If you have a building management system, you can install an enthalpy sensor so that the night purge doesn’t happen when the air is too humid.  (Your air conditioner has to work harder to cool humid air).  If you don’t have a building management system, you can watch the weather, and turn off the night purge when humidity is high.  Remember to turn it back on when the humidity drops.  Normally in Saskatchewan, we have few enough humid nights that leaving your night purge system on is better than leaving it off.