In 2007 I was the facility asset manager for a facility in South Padre, Texas. I received a call to investigate a severe mold issue they had at one of their buildings. When I inspected the property, I noticed that they had a brand new 10 ton HVAC unit. Upon close review of the original design drawings, it showed a 7.5 tons HVAC unit, so I asked the person in charge why was this unit replaced by a 10 tons unit. The technician in charge answered me that he was told by the contractor that they had a 10 ton unit in stock of a better quality, a better price and bigger in size than the required 7.5 tons. So he assumed that bigger was better and thought that he was getting a bargain. Indeed he saved around $4,000 for the unit, however, since mold is such a big deal in Texas, the agency ended up having to pay $350K in remediation, disposal and replacement of all drywall and carpeting of the spaces occupied and of top of that they had to replace the HVAC unit again for a 7.5 tons as specified by the original drawings. The moral of the story is to follow the original design when replacing an HVAC unit or consult an experienced mechanical engineer if replacing an HVAC and the space has significantly changed the occupancy load or has been remodeled since the original design.

 About the Author: Mr. Ivan R. Meneses, PE, CEM, EBCP is a professional engineer with a Master’s degree in Construction & Facilities Management and 20 years of experience in indoor humidity issues in government and commercial facilities. His Master Thesis from GA Tech involved a Case Study to solve Indoor Humidity issues at a federal government housing complex. Mr. Meneses is also a certified energy manager and certified Existing Building Commissioning Professional. Mr. Meneses can be reached at