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Should You Replace Air Conditioner And Furnace Together?


Wondering if you need to replace Air Conditioner, furnace or both? Replacing an air conditioner can be costly. Combine this with the cost of replacing a furnace, and you may just be wondering if it’s really necessary to replace the two of them at all.

The truth of the matter is, in most instances, replacing your furnace at the same time as your air conditioner is one of the best ways to guarantee that you’re receiving top-quality performance and efficiency. This can also save you money in the long-run. 

There are a couple of ways in which we can determine whether or not the pair should be replaced together. 

When You Should Replace Your Air Conditioner and Furnace Together

Air conditioners typically live to be 15-20 years old, while furnaces tend to have a longer lifespan of around 15-30 years. Despite this, we often suggest that homeowners replace both their air conditioner and their furnace at the same time. In order to understand why, let’s take a look at the different components and what they do.

Air Conditioners

An air conditioner can either come as a split system (with an indoor and outdoor unit) or a packaged system (the unit is in one place). It distributes air throughout the home and ensures airflow. 


Furnaces provide your home with heat and work directly alongside the air conditioner, which distributes the warm (and cooler) air throughout the property. The fan, also known as the blower, is relied upon for airflow. 

While it’s not technically required to replace the two together, in the majority of cases, we’d highly recommend it. This is due to the fact that air conditioners rely on furnace fans (the blower motor) for airflow. In order to ensure that your new air conditioner is working as efficiently as it can be, it’s a good idea to replace both as brand new. 

If you opt-out of replacing the pair together, you could end up with an inefficient system. This usually happens when your new air conditioning unit has increased efficiency with a SEER rating of over 16. If your furnace is more than 10 years old, it likely has an outdated blower motor and won’t be able to contribute to the overall efficiency of the new HVAC system. This will end up as an extremely costly and ineffective expense to you. 

While the system will still function, you won’t be able to use it to the best of its ability and it could result in premature failure. The increase of power from your air conditioner can also cause damage to an older furnace, as it may not be able to handle the stronger capacity. Balance is important, and we wouldn’t suggest doing this. 

It’s also a good idea to consider the cost of replacing your units. When replacing your air conditioner, the addition of a furnace to the process often costs far less than replacing a furnace on its own. This can save you anywhere from $1,000 to $4,000. 

If your furnace and/or air conditioning unit is located in an area that is extremely difficult to access or work in, we’d also recommend having both replaced at the same time. When a contractor is required to squeeze into a tiny crawl space or work in uncomfortable conditions, this could be potentially hazardous. The difficulty of an installation can significantly hike up the price of a replacement, and you won’t want to be paying for this twice. 

Replacing the two at the same time can also save you money down the line. You’re much more likely to get an extended lease of life out of an entirely new system than when half of it is already entering old age. Maintenance costs and repairs can build up, and you may find that mid-way through, you have to replace the furnace anyway. 

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When You Shouldn’t Replace Your Air Conditioner and Furnace Together

As we mentioned earlier, furnaces tend to have a far longer lifespan than air conditioners. There are only three cases in which we’d suggest waiting on a furnace replacement: 

10 years or less: If your furnace is less than 10 years old, it may just be able to last until the next time you go to replace your air conditioning unit. 

Maintenance: If your furnace is less than 10 years and you feel that any possible maintenance or repair costs during the next 10-15 year period will be low or worth the cost — then you may want to consider holding off on replacement. 

SEER rating: If you choose a more traditional air conditioning unit with a SEER rating of 14 or less, your furnace should be able to function efficiently alongside it. 

It’s also important to note that you should never replace your air conditioner and furnace together based solely on the fact that a salesperson is telling you to. It’s important to take your own personal situation into account. 

Making a Decision

We believe that a well-matched air conditioner and furnace generally makes for a more efficient and cost-effective solution, but when it comes to making the decision on whether or not to replace them at the same time, the decision is ultimately in your hands. Nevertheless, we’d highly suggest speaking with a professional to go through your options with you. 

Cooper’s Plumbing and Air can provide you with a consultation and talk you through your options so that you’re sure you’re making the right decision for your home. To find out how much a full replacement would cost, book your service, or to enquire further — give us a call today!

To see how much it would cost to just replace the air conditioner versus replacing the entire heating and cooling system, contact Cooper's Plumbing and Air for your no obligation, FREE estimate.