Hartz Heating & Cooling Inc. has been responsible for all of the repair and maintenance of our HVAC units for years. Our most recent maintenance seems to have gone well although we aren't sure how to confirm that any work was actually completed. However, they have been consistently reliable for us and we haven't used any other company. Hartz Heating & Cooling Inc. are always on time and communicative. It is this consistency in quality and courtesy that makes us continue to use them time and again.