Dehumidification Strategies for Commercial Properties This Summer
For commercial property managers and building owners, summer humidity control is not just a comfort issue — it is a building science and risk management imperative. Relative humidity above 60% sustained over weeks and months drives mold amplification, accelerates material deterioration, creates liability exposure from tenant and occupant complaints, and can result in costly remediation projects that dwarf the cost of prevention. This summer, implementing the right commercial dehumidification strategies is one of the most effective ways to protect your investment and avoid costly remediation.
Understanding the Sources of Indoor Humidity in Commercial Buildings
Commercial buildings face humidity loads from multiple simultaneous sources. Outdoor air infiltration through the building envelope brings in warm, humid summer air. HVAC fresh-air ventilation requirements — which in commercial buildings are typically higher than in residential applications — introduce significant latent load that must be treated before conditioned air is delivered to occupied spaces. Occupant density generates both sensible and latent heat. And moisture sources within the building itself — kitchens, restrooms, cooling towers, and process equipment — contribute to total humidity load.
Effective dehumidification strategy begins with identifying which of these sources is dominant in a given building. A building with high occupant density and significant fresh-air ventilation requirements needs a different solution than a large storage or light industrial facility with few occupants but significant infiltration through a leaky building envelope.
HVAC-Based Dehumidification
The primary dehumidification tool in most commercial buildings is the central HVAC system. Properly sized and maintained cooling equipment with adequate airflow across clean evaporator coils provides latent as well as sensible capacity. However, there are circumstances in which standard HVAC systems cannot maintain acceptable humidity levels even when operating normally. These include buildings with high fresh-air ventilation rates, buildings with high internal latent loads, and shoulder-season conditions where outdoor temperatures are mild enough that cooling demand is low — but humidity remains elevated.
For buildings with persistent humidity challenges, dedicated outdoor air systems (DOAS) with energy recovery ventilators (ERV) can treat fresh-air ventilation loads independently of space conditioning. This separates the latent and sensible loads, allowing the primary HVAC system to focus on space temperature control while the DOAS handles incoming humidity. Buildings that have undergone significant air-sealing or envelope improvements without corresponding HVAC modifications are often good candidates for this approach.
Standalone and Supplemental Dehumidification
In areas of a commercial building that are not served by central HVAC — or where HVAC cannot maintain adequate humidity control — standalone desiccant or refrigerant-based dehumidifiers provide supplemental capacity. These units are particularly valuable in crawl spaces, basement mechanical rooms, storage areas, server rooms, and spaces with frequent envelope penetrations that allow humid air infiltration.
Commercial-grade dehumidifiers are rated by pints-per-day removal capacity at standard test conditions. Selection should be based on the actual humidity load of the space at summer design conditions, not on unit size or price. Undersized units will run continuously without achieving target humidity setpoints, increasing energy consumption without solving the problem. A qualified mechanical engineer or building scientist can calculate design dehumidification loads and specify appropriate equipment.
Building Envelope as the First Line of Defense
Mechanical dehumidification is more effective — and less expensive to operate — when the building envelope limits humidity infiltration. Air sealing of common infiltration pathways — wall penetrations, electrical conduit entries, window perimeter gaps, roof-to-wall transitions, and foundation penetrations — reduces the outdoor humid air that mechanical systems must treat. Vapor retarders in wall and roof assemblies limit moisture diffusion through building components. Properly functioning exhaust systems prevent pressure imbalances that would otherwise draw outside air in through the envelope.
A blower door test or tracer gas pressurization test can quantify a building’s air leakage rate and identify major infiltration pathways. For commercial buildings with significant humidity issues, this diagnostic step is often revealing — identifying air sealing opportunities that are far less expensive to address than the ongoing energy and maintenance costs of running oversized dehumidification equipment to compensate for envelope deficiencies.
Monitoring and Documentation
Regardless of the dehumidification strategy employed, humidity monitoring is essential to verify performance. Low-cost data loggers that record temperature and relative humidity at configurable intervals can be placed in problem areas — crawl spaces, storage rooms, server areas, and building perimeter zones — to generate a continuous record of conditions. This data serves two functions: it confirms that the dehumidification strategy is achieving target conditions, and it provides documentation in the event that mold or moisture damage is later discovered and becomes the subject of an insurance claim or legal dispute.
EES Group’s engineers and industrial hygienists can assist commercial property owners with humidity load assessments, dehumidification system evaluations, building envelope diagnostics, and cause-and-origin investigations when moisture damage has already occurred. Proactive engagement before damage develops is always the most cost-effective path — but when damage does occur, accurate forensic documentation is essential to a fair outcome.









