Every time the heating and A/C started running, I would hear a strange noise, then it sounded like tiny balls rolling on a surface, especially if one was in the sunroom. I searched the entire home but could not find where the noise originated. I eventually gave in and called for home services, but the first thing was for the heating and A/C professional to find out if the noise was indeed in the conduits, as I suspected and also to replace it with a smart heating and A/C system. When he came, he said that the best cause of action was to do a duct cleaning because then we could unfasten everything in the ducts! After inspecting the heating and A/C equipment, he said all needed for the replacement was service and a smart temperature control. The rest, such as the smart vent, could follow later on since I was on a limited budget. That was a relief because I thought I would have to replace the entire system or the better part! She also showed me all the dirt plus dust that the air filter had trapped plus told me to increase the frequency at which I replaced it. She also encouraged me to buy a whole-home air cleaner since the air purification helped in the heating and A/C was not enough to maintain the indoor air quality. The air cleaner would ensure that the air quality in the home was high. When the heating and A/C worker finished with all matters concerning air purification in my home, we finally found out what was causing the strange noise. After the cleaning, he discovered 3 marbles in the conduit leading to the sunroom. I had no idea when or how the marbles ended up in the duct, but I was glad to be rid of the noise plus the dirt.