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Should You Replace Your Air Conditioner and Your Furnace at the Same Time?


Some people are hesitant to replace their air conditioner and furnace at the same time, due to the cost. Or, maybe their air conditioner needs replaced, but they’re not sure whether their furnace really needs a replacement! Today, we’re here to tell you when you should replace your whole HVAC system, and when you shouldn’t.

A/C vs. furnace

It’s true that furnaces have a longer lifespan than air conditioners. Air conditioners last around 12 years, to 20 at maximum … whereas furnaces tend to last 15 to 20, and sometimes even longer!

However, despite this apparent mismatch in lifespan, we’ll explain one reason why it’s important to have what’s called a “matched system,” which is another term for replacing your whole system at the same time:

What is a matched system?

Basically, the fan in your system is used by the furnace (in winter) and air conditioner (in summer).

But the fan is connected to the furnace, not to the air conditioner.

That means, if you get a new A/C system, but you don’t get a new furnace, then you have your new A/C using an old fan from your old furnace! This makes your new air conditioner operate much less efficiently than advertised.

Just to give you an example, let’s say you just bought a super high-efficiency A/C that has a high SEER rating. (That’s Seasonal Energy Efficiency Ratio — basically dividing the cool air produced by the energy used to produce it.)

Still, if your furnace is old and has an old fan motor, then your air conditioner won’t be operating at its high SEER rating. You paid good money for your air conditioner, and now you won’t see the results!

But, do you have to replace your air conditioner and your furnace at the same time?

As you can see, if you don’t replace your furnace at the same time as your air conditioner, the older furnace also hampers the efficiency of the new air conditioner.

But what if you aren’t buying a variable speed or two-speed air conditioner, that needs a new furnace to keep up with it?

Well, if your furnace is only 8 to 10 years old, or newer, it may be worth holding off on the replacement. It’s true that it’s not recommended to mix and match, with an old heating system and new cooling system or vice versa.

But in some situations, if your furnace is not that old and your air conditioner is not so high-efficiency that replacing both at the same time is a big deal … you may opt not to replace your furnace and air conditioner at the same time.

Most of the time, customers are in a situation where it would make the most sense, in terms of the lifespans of both systems, to replace at the same time!

The real key is doing business with a company and a tech you trust here in the Yakima, Ellensburg, and surrounding area. We’ll tell you whether it makes the most sense to replace your furnace and air conditioner at the same time.

Here at ThermAll, we pride ourselves on our ability to assess your system and to help you make the best final decision for your home. Give us a call at (509) 248-8368 or contact us online today!