My mom's heating system may be oversized

I asked them why and they told me that they are known for not putting in the right size Heating, Ventilation and A/C system.

My parents have a condo that is pretty old. They still live in the same condo that I was born and raised in. The condo is about 45 years outdated however it is still in great condition. My parents are much older now and the things that they could do ten years ago they can’t do now. My dad used to be so strong and could carry heavy things around the house. He was legitimately handy and did a lot of the landscaping and reconstruction of their home, now that he’s much older he doesn’t keep up with the landscaping. I’ll go over to my parent’s condo just about every weekend to do the landscaping and help them, and recently they called me up about their current Heating, Ventilation and A/C system. They had an Heating, Ventilation and A/C system put in last yearby an Heating, Ventilation and A/C specialist. The other afternoon when I was talking to my friends they told me that I should have went with the Heating, Ventilation and A/C specialist that I did for my parents. I asked them why and they told me that they are known for not putting in the right size Heating, Ventilation and A/C system. Therefore when my parents called me the other afternoon about how loud their Heating, Ventilation and A/C system was sounding I figured that they must of had the wrong size system in their house. My parents told me that the fan was set to the lowest setting and they couldn’t even hear themselves think. I’m going to call another Heating, Ventilation and A/C provider to take measurements and see if the Heating, Ventilation and A/C system is oversized.

new hvac