Christmas shopping could have been livelier but with everything going on in the world we were grateful that we could even go shopping. The first stop was at the mall since that is where most of the stores were. As we were going in, I noticed a commercial HVAC provider truck they were likely here to do HVAC system maintenance. During our many stops in the mall, we came across a certain store and the first thing I noticed was that it was under renovation or something related because there was so much exposed ductwork. I assumed that they were doing duct cleaning. My curiosity drove me to ask the cooling expert what was wrong with the HVAC unit and he told me that they were fixing a leak in the air duct in that particular store. He even showed me the HEPA filter that they would use in air purification to help create a more conducive environment improving air quality. I was very impressed by how well they worked. It was strange that they actually scheduled maintenance during a peak season but I guessed it must have been an emergency that had to be attended to immediately. As I was leaving, I remembered something and went back to ask the professional how often was one required to clean a washable filter. He told me every three months was adequate and also advised me to have residential HVAC professionals check and clean the furnace in case I was not sure not to go about it so as not to cause any irreplaceable damages. He promised to take better care of the unit.