If the furnace or boiler was manufactured earlier than 1986, it is just waiting to fail. Dirt, hard work and time have decreased the efficiency. Would you have much confidence in driving a 1986 car to California in the middle of winter? Your heating unit will be working as hard as driving that car back and forth to California two to three times this winter.
 

How much money do you want to put into the existing unit if you have an emergency breakdown? Everyone wants to think their heating system will only break down when temperatures are mild and they will have plenty of time to consider choices. The reality is that most break downs occur when temperatures are cold. The system is starting and stopping frequently, just like in a traffic jam. Often, you have to make a quick decision to get the heat back on or face freezing water pipes.
 

If the heating system was manufactured before 1993, it is time to start thinking about a planned replacement. Start thinking about how long you will be staying in your current home. That will help determine how efficient you will want your new furnace to be. However, town homes or condo owners often are very limited to the type and efficiency of the new heating system. Boilers also have limitations. If your system has been cleaned each year and you change filters every three months – that is great! You should be able to add at least 5 more years before you need to worry about replacement.