To repair or replace that is the question. When it comes to HVAC, you need to service it a lot. If the HVAC is left dirty, worn and rusted, it will just shut down. Then comes the question of paying for that huge HVAC repair or just getting all new HVAC entirely. Most HVAC businesses push for the new HVAC install. It gives them a higher commission rate. They hit you with the HVAC device, HVAC installation and their time and labor. A huge bill for you and a nice little bonus for them. Repairing the HVAC is a lot of work and messing around for them. Also, there is no guarantee the hefty HVAC repair will work. It is a safer bet for the HVAC expert to push for a new unit. But, you can tell when the HVAC is able to be revived and when it is not. For example, a furnace has a lot of parts that can go wrong. A fan can be damaged, the motor belt is worn or the furnace filter is just dirty. These are low to moderate heater repairs. The HVAC technician can get it done in a day. Not a fun day for you, but the heater is back to business. But, if the furnace has a broken heat exchanger, it is time for a new furnace. A new heat exchanger is basically the same cost as buying another furnace. Also, taking out the heat exchanger is sort of dangerous. It releases carbon monoxide into the home. In this case, don’t make the HVAC contractor do this.