Why Warehouses Overheat Even With Air Conditioning Installed
A Common Frustration With a Fixable Cause
It is one of the most frequent complaints in UK warehousing: a cooling system has been installed, the equipment appears to be functioning correctly, but the shop floor is still uncomfortably hot. Staff are uncomfortable, productivity suffers, and the system that was supposed to solve the problem appears to be doing very little.
In almost every case, the root cause is not equipment failure. It is a fundamental design error an approach to warehouse cooling that ignores the specific physics of large, high-bay spaces.
Understanding Stratification in High-Bay Spaces
The primary culprit in warehouse overheating is stratification. In any large space with significant ceiling height, warm air naturally rises and accumulates in a dense layer near the roof. This layer of trapped hot air acts as an insulating blanket, making the upper structure of the building retain heat and preventing the cooled air produced at lower levels from having any meaningful effect on the overall temperature experienced by people working below.
In a warehouse with a ten or fifteen metre ceiling, the temperature difference between floor level and roof level can be ten degrees or more. A standard air conditioning system installed without accounting for this will cool the air at the point of discharge and then watch that cooled air immediately mix with the hot stratified layer above, limiting its effectiveness at floor level where it is actually needed.
The Role of Destratification Fans
The solution to stratification is not more cooling capacity it is airflow management. Destratification fans are designed specifically to address this problem. Mounted at high level, they drive the hot stratified air back down and circulate it through the space, breaking up the thermal gradient and ensuring that the conditioned air produced by the cooling system reaches the people and processes at floor level.
When destratification fans are combined with a properly designed evaporative cooling or mechanical ventilation system, the result is consistent temperature throughout the entire height of the building not just at ceiling level where the air conditioning discharge happens to be.
Other Design Mistakes That Cause Overheating
Beyond stratification, several other common design errors contribute to warehouse overheating even where air conditioning is present. These include undersizing the cooling system for the actual heat load which includes not just outdoor temperature but also heat generated by lighting, machinery, vehicles, and people failing to account for solar gain through rooflights, and positioning cooling equipment where it serves part of the building effectively while leaving dead zones elsewhere.
Loading bay doors present a particular challenge. When large doors are frequently opened, significant volumes of warm external air enter the building, overwhelming a system that was designed for a sealed environment. Effective warehouse cooling design must account for this reality rather than assume doors will remain closed.
Solving the Root Cause, Not the Symptom
Celsius Design focuses on identifying and resolving the underlying causes of warehouse overheating, rather than simply adding more cooling capacity to an already misdesigned system. Our approach begins with a thorough assessment of the building, its heat load, and its airflow characteristics before any equipment is specified.
A free site survey is the starting point for every project. Contact Celsius Design to arrange an assessment of your warehouse cooling performance and discuss the changes needed to achieve consistent, effective temperature control.
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