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Should I Replace the Furnace When Replacing the Air Conditioner?

HVAC systems require regular maintenances to prevent them from breaking down abruptly. This is because they are such an essential component in your home that offers comfort throughout the year. However, maintenances and repairs are, to some extent, not sufficient.

Replacing old and damaged systems goes a long way in solving substantial repair bills, frequent malfunctions, and accidents. The HVAC system comprises an AC and a furnace, which work in sync to cool indoor air in your home. After some time, it’s always recommended to replace the AC due to several reasons. This then begs the question, should this replacement be done on the furnace too? Let’s try to break it down.

What Can Cause A Furnace To Stop Working?

Functions of the Furnace in the HVAC System

You need to understand how the furnace works in case of an emergency so that you can quickly troubleshoot problems. The furnace is usually installed inside your house and attached to the condensing unit and thermostat.

This process is a continuous cycle that ensures that you have a regulated environment inside your home, even when the outdoor weather conditions are unbearable.

Here are the steps that it takes for the furnace to heat indoor air.

  • The thermostat in your home detects temperature changes and signals both the furnace and the blower fan in the AC,
  • Outdoor air blows into the furnace, and your furnace’s gas or fuel source starts heating the air.
  • The temperature of the air rises, and warm air is pushed through the ductwork,
  • After the air temperature reaches the desired level, the thermostat sends a signal that shuts the furnace and the blower motor.

However, these machines can’t practically provide service forever, even when taken good care of. Thus, there comes a time when you have to consider replacing a unit or the whole. To help us determine what needs to be changed, let’s see how long they can work.

Average Lifespans of AC units and Furnaces

Air Conditioner or Condensing Unit

Ideally, a well-maintained AC can last upwards of 15 years. It depends on how well the system is maintained and how often you run your air conditioning unit.


The furnace, on the other hand, lasts a little longer. Furnaces have an average lifespan of 15-30 years. However, this depends on factors such as usability, maintenance, and model.

Replacing HVAC Systems – What to Consider

Since both AC and furnaces are highly dependent on each other, ensuring that they are working efficiently together is crucial. This is done by repairing and making sure all parts are working correctly.

Provided that the furnace and the AC have deferring lifespans, it becomes a little challenging to decide if to replace both or one at a time. But here is the kicker, the lifespan of the furnace is almost double that of the AC. This means that you can use one furnace with two AC units.

Therefore, should you replace the furnace and AC at the same time? Yes, if the furnace is twice older than the AC or is completely broken. And no, if the furnace was installed at the same time as the AC or condenser unit.

Experience You Can Trust

Are you experiencing HVAC or air conditioning problems in your home or office?

You have found the right solution to all your heating and air conditioning issues. At Absolute Airflow, we have a culture we live by where we assure you of no hidden charges, up-front flat-rate pricing, and no overtime charges or surprises.

For Quick Emergency Help – Please Call (833) 482-2626 Immediately

Our state-licensed and certified HVAC technicians are always available to help you.

Absolute Airflow is a 24 Hour Emergency HVAC Service Contractor

Customer Reviews

Claudia M.

Scott, along with his associate, Gabe, did a great job. They were both professional and friendly. Scott explained in enough detail to help me understand how my a/c unit works-he’s very informative. Have was a great help, cutting the time it took to clean and install the HVAC equipment. I liked that they were both pet friendly, that’s also important for me. I’ve been a customer of absolute Airflow for a couple of years and they are a great company …

Ty S.

Have had nothing but amazing experiences with Absolute Airflow from the beginning. We have had a few issues here and there but Absolute has always sent someone out quickly and stood behind their work. Most recently they sent out Spencer and he was the best technician we’ve ever had! He was extremely respectful and polite, he also took the time to thoroughly talk me through and help me understand the genesis of our various issues we were encountering. Definitely hope …

Ian S.

My requested service was set up by Marcus who came to my home to evaluate and was prepared with options and great prices for my water heater replacement. Was able to get an appointment within 3 days as there was no emergency. My install tech James was amazing, He was very respectful and maintained a clean and organized work area as the installation was in the home. The removal, prep, and installation of new water, gas, and venting took approximately …

Richard S.

I can’t express enough how impressed I am with this company and especially Anthony Belt. Anthony was so thorough and patient with my wife and me. The impressive part was he was able not only to identify all the problems with my heating and ac but went above and beyond to fix all of them! My electrical bills were over $500 a month during the ac months and now they are less than $200! Not only am I saving a …

Patrick K.

I haven’t posted any reviews in a long while but here I am thanks to SCOTT with Absolute Airflow. The warmer Cali weather is around the corner and as a responsible homeowner, I decided to get my HVAC system checked out and tuned up before the summer heat. Scott provided us with the full red carpet experience. His knowledge, quality and care put into his work, and professionalism were all outstanding. Replaced fan motor due to oil leak (a normal …

Liem H.

Outstanding experience from the start. I’ve been a member of Absolute Airflow for almost 2 years now. Since then, I’ve had my system maintained twice a year. Every service has been very thorough and professional. Each time, everything was explained to me in terms that I would understand, coupled with plenty of photo documentation. Which I appreciate so much. Knowing that I would have to replace my aging system. I dreaded the coming expense and experience. But my fears were …