Why can’t I have an all-beach house air cleaner installed?

He asked if I had ever thought about purchasing a portable air cleaner

I have an older Heating, Ventilation plus A/C system plus I wanted to have an all-beach house air cleaner installed. When the Heating, Ventilation plus A/C serviceman arrived to inspect our Heating, Ventilation plus A/C system, he told me he didn’t guess it would work. I needed to use HEPA air filters with the air cleaner, plus our Heating, Ventilation plus A/C system wasn’t made to use HEPA air filters. I tried to understand what he was telling me, although I was have a mind block. I couldn’t wrap our mind around what he was trying to explain to me. He brought a HEPA air filter in from his repair van plus shoed me the difference between our air filter plus the HEPA air filter. He said they also had UV lights in the air cleaner. I could have the air cleaner if all I wanted was the UV light system, although I couldn’t use the HEPA air filter. Some people chose to use just the HEPA air filter plus not the UV light, although I didn’t have that choice. He told me that if I wanted a whole beach house air cleaner with a HEPA air filter, i would need to get a newer Heating, Ventilation plus A/C system. I couldn’t afford to get a new Heating, Ventilation plus A/C system, plus I told him so. He asked if I had ever thought about purchasing a portable air cleaner. They worked just as well, although I would need to have 1 for each room, or switch the portable air cleaner from room to room. I didn’t care about the inconvenience of this either, so I gave up on the idea.
air conditioning company