When will the HVAC system need replaced?

I have lived in our home for the last twenty years, and I often ponder when we will need to have the HVAC system replaced.

We have our annual cleanings for the AC unit done, on a regular basis.

We know that our HVAC system was in the house when we moved in. We didn’t think it was new, but even if it was, it was twenty years old now. Either way, it was coming time when we would need a new HVAC system. The saving grace was that we had a boiler system in our home. Our HVAC tech told us that a boiler could possibly last forty years instead of twenty. There is very little maintenance needed for a boiler and there aren’t any air filters to change. Our maintenance has only been done on the air conditioning, except for the new igniter switch we needed for the boiler. My husband takes good care of all of our HVAC equipment, so we don’t really see our actual HVAC technician very often, unless he is there for a meal. I forgot to tell you that our HVAC technician is also our son. A couple months ago, he was at our home and he heard an odd sound coming from the air conditioning. He told us that our fears were about to be founded. When he looked at the AC unit, he said it was about to die on us. Installing a new air conditioner was minor to needing to install the entire HVAC system. He said that when we got the next AC unit, we could consider putting in a new boiler. That will be another twenty years from now.
Heating equipment