Here’s a question we see homeowners asking a lot, “When should I replace my furnace?

It’s a tough question for a homeowner to answer objectively because it’s so darn expensive to replace a furnace. But you know you need to say goodbye at some point. So when is the best time to do that?

Here are 3 signs that it’s time to replace your furnace.

Furnaces live an average of 18-20 years, depending on if you had it professionally maintained or not.

Age isn’t everything, though. The cost to keep the furnace running will give you more concrete reasons to replace or not.

Like an old car, an old furnace that starts to have costly breakdowns is signaling that it’s near the end of its usable life and needs to be replaced soon (within the next 2 years or so).

The question then becomes, “How expensive does a furnace repair need to be before it’s not worth it?”

It depends on how old your furnace is and the cost to get a new furnace. A good rule of thumb is, no matter the age of the furnace, if the cost to repair is 50% of the cost of a new furnace, you should replace it.

But for less expensive repairs, you should be less resistant to replacing the furnace the older it is. So if the furnace is 20 years old, and the cost to repair the furnace is only 10% of the cost of a new furnace, you should probably replace it (because it’s more likely to break down again soon).

For example: You have an old furnace that’s 20 years old and the repair would costs you $150, and the cost of a new furnace would be $1,500, then you should look at getting it replaced rather than repairing it.

Ask one of our experts to get a more detailed assessment about the cost vs. benefit of replacing your furnace based on your situation.

Even if your furnace has a few years left in it, it may not be cost efficient to keep it if your energy bills during the heating season are high due to the furnace’s horrible efficiency.

With that in mind, you need to assess how much it’s costing you just to keep the current furnace you have versus how much you’ll save with a new furnace.

AFUE is a gas furnace’s efficiency rating, represented in a percentage. It stands for how much of the gas it uses to heat your home. So an 80% AFUE furnace uses 80% of the fuel to heat your home, the rest goes up the flue pipe—wasted. That means for every dollar you use to heat your home, 20 cents is wasted.

This chart will show you how much you’ll save for every $100 you normally spend on heating by upgrading to a higher efficiency furnace.

So if you’re upgrading from a 60% AFUE furnace to a super efficient 90% AFUE furnace, you’re saving $33.33 for every $100 you normally spend on heating. Find your last year’s heating bills and do the math. It’ll be crystal see how much you’ll save each year.

The savings from a higher energy efficiency furnace may motivate you to replace your current furnace earlier than you expect.

As you can see, none of these factors (age, cost to repair, energy efficiency) alone can tell you if you need to replace your furnace. They should be weighed together to replace furnace.

To help you make the best choice possible, we encourage you to contact a trusted heating company for help assessing if you should replace your furnace or not.