Last winter we told them several times there was a strange smell coming from the vents with the heat on. Multiple techs AND a manager came out to "address the issue" by gaslighting us and telling us there was nothing wrong. Finally this season we called a different company and the tech walked around the house and found the issue within seconds. He was appalled Charles hadn't noticed it. The intake and exhaust vents were inches apart facing down in the same direction so that when the wind blew slightly the exhaust was sucked back into the house. We had been breathing in harmful exhaust for AN ENTIRE WINTER. It wasn't an ideal fix but we added some PVC pipe to the intake to move the intake further away from the exhaust. No more smell. Problem fixed. It only took another company giving enough of a shit to walk around the house.
Previously they flooded our basement with a disconnected condensate tube, missed gas leaks despite checking, and straight up refused to check the flue cap on the roof to see why the flue pipe was rusty (water was getting in cause the cap was in fact messed up). We spent thousands purchasing a water heater and furnace from them and all it took was less than $200 with the other company to fix everything they missed.
Please for the love of god do not give these people your money this winter, avoid the big names and find a smaller company that cares about keeping your business.