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Commercial HVAC, Preventive Maintenance Agreements

Your HVAC System Could be the Cause of Your Smelly Building

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Last Updated on April 30, 2019


Few complaints drive customers away faster than unpleasant odors from food, mold, or restrooms. Lingering odors in your restaurant, health club or store could spell disaster for your business.

Psychologists studying the effects of odors have documented that people quickly become conditioned to slight odors. This means that while you and your employees stop noticing an odor very quickly, your customers notice as soon as they walk in the door, and they will be walking out the door in a hurry.

Odor problems can be surprisingly difficult to solve, and the causes are not always immediately apparent. If you’ve noticed an unpleasant odor, you’ve probably already tried the obvious remedies like cleaning and deodorizers. If these haven’t helped, then the culprit may be your HVAC system. Poorly designed or maintained ventilation, heating and air conditioning systems can push air in the wrong direction, spreading nasty odors that can hurt your business.

Controlling odor is all about regulating air flow

HVAC systems move air through buildings. Exhaust fans, clothes dryers, built-in vacuum systems, dust collection systems, and range hoods all remove air from a space. Some ventilation systems, air conditioners and heating systems push air in. When there is more air mechanically expelled from an area than air supplied, negative pressure causes air to be drawn in from outside the room, resulting in negative air flow. Conversely, when more air is pushed into your space than removed by exhaust, positive air flow is created. Generally a positive air flow is ideal for comfort, however there are some circumstances where a negative airflow is not only beneficial, but necessary.

Negative air pressure can be used to move odors in a desired direction; that is, away from your customers. A negative air flow is created by ensuring that the amount of air exhausted out of the zone is greater than the replacement air, also called makeup air, entering the zone from your clean air delivery system.

In addition to controlling odors, there are many other situations where you want to prevent air from flowing from one area to another in your building. The use of negative air pressure can prevent not only the spread of nasty odors, but also airborne illnesses and other contaminants.

  • Commercial kitchen ventilation systems should be designed to create a negative air pressure in the kitchen, where those strong odors are lurking, so that conditioned air is pulled from the dining room toward the kitchen. This scenario prevents odor from traveling from the kitchen toward the dining room where customers are enjoying a meal. Kitchens also need to be designed for worker health and safety as well as odor control. Negative air flow in the kitchen reduces hazards from smoke and fire, and it also removes air pollutants generated by cooking appliances that can cause breathing difficulties for your employees.
  • Restrooms require negative air flow so that clean air flows in, and smelly air is drawn out through an exhaust fan. Without negative air flow in the bathroom, those offensive smells can drift out into unwanted areas where they will offend your customers.
  • Hospitals keep people with communicable diseases in negative pressure isolation rooms. Negative pressure causes air to flow into the room and prevents air, and airborne viruses and bacteria from exiting the room into other parts of the hospital. Air is drawn out of the room only through filtration systems that capture the contaminants.
  • Laboratories and manufacturing facilities working with hazardous materials need to create work areas with negative air flow, to ensure that people throughout the building are not exposed to chemical fumes and harmful airborne contaminants.
  • Health Clubs with musty, moldy locker rooms will not only lose customers, but can even make them sick. Proper air flow in a health club moves air from the fitness areas toward the dry section of the locker room, and then toward the wet shower area, where it is finally expelled from the building by a powerful exhaust system. This design not only prevents odors, but also controls dangerous mold growth.
  • Wastewater treatment facilities and chemical plants can have odor situations on a much larger scale, and need specially-designed odor control devices to reduce odors in the surrounding neighborhood. However, these devices may not work as designed unless the facility’s ventilation system uses negative air flow to prevent odors from escaping before they are captured by the odor control devices.

Proper inspection and maintenance by an HVAC expert can help

If you have an odor problem, it’s time to bring in an expert to take a look at the design and condition of your HVAC system. Every day that you wait, hoping that scented candles and deodorizers will do the trick, you will be losing business. Your customers will be posting negative reviews on Yelp complaining about how the nasty smell in your restaurant made them lose their appetites.

Start with an inspection and evaluation of all your heating, cooling, and ventilation equipment by certified professionals. The inspection may reveal that design changes are needed in order to create negative air flow conditions in specific areas to move air in the right direction. In this case, you’ll need a contractor with the skills and experience to implement an effective solution.

Sometimes, inadequate maintenance of exhaust systems, clogged vents or air filters, or even open windows in the wrong places can disrupt the air flow and spread odors throughout your building.

In order to appropriately diagnose and manage the problem, it’s best to establish a relationship with an industry leader. A quality HVAC Contractor will visit your property and perform an assessment in order to effectively diagnose your problem. Once you’ve successfully addressed your immediate needs, consider a preventative maintenance agreement to keep your system running up to par.

To learn more about establishing a good vendor relationship and choosing a preventative maintenance contract, download our guide to HVAC Preventative Maintenance Contracts: How to Choose The Best One for Your Infrastructure.


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