At a certain point, the cost of maintaining and repairing a boiler can exceed the price of replacing it with either a new boiler or a different system altogether. Here are a few reasons your boiler might need to be replaced. 

• Energy Bills: Older systems run less efficiently and heat your home less effectively. If you notice that your energy bills have been steadily rising, you might want to consider an upgrade.  
• Age: On average, a boiler is designed to last 10 to 15 years. When it comes to the classic question of repair or replace, you need to weigh the cost of either against how long the system can last. While repairs might be cheaper in the short term, once a boiler is 15 years old, you will start to need repairs so frequently that their collective cost is higher than the cost of replacement. 
• Noise/Leaking: There are a variety of common boiler problems to be aware of. Banging, gurgling, or whistling can all be signs that you either need repairs or a replacement. Likewise, leaking is a serious sign that you need a contractor to take a look. Another thing to be on the lookout for is the color of the pilot flame. The flame should be blue; if it is yellow, that is a sign that something is wrong.