When your furnace or air conditioner needs to be replaced, it is often tempting to just replace one of them because of the upfront costs.

As it turns out, replacing both the furnace and AC together may actually end up saving you money in the long run – even more depending on what time of the year you replace your HVAC system.

In this article, we will discuss the advantages of replacing both your systems at the same time, and when it is best to do so.

Matched Technology

One of the biggest advantages of replacing your systems at the same time is that they will have matching components and technology. This will ensure that you get the maximum energy efficiency from them, saving you money.

Since the furnace and air conditioner shares several components, including the air handler and blower, if you mix old and new technology, you may not be able to utilize the newer technology that makes modern systems better. 


Installation Costs

Replacing the systems together will save on overall installation costs because it will be easier for the technician to replace them, and you will not have to pay for the second installation when you would have had to replace the other system.

The installation process itself will be less complicated because they will not have to detach and reattach parts from the older system. 

You also want to make sure you don’t have an oversized heater and AC. You’ll be less comfortable, and your new system will break down years before it should.


If you combine a new system with an older system, many manufacturers are not required to honor their warranties on the new system.

While this might not always be the case, it is something to consider when making the decision.

And remember: getting an annual heater tune-up in the fall and AC tune-up in the spring keeps your warranties valid (along with providing other benefits)

High Efficiency Systems

Depending on the efficiency rating of the new system, sometimes it is highly recommended or even required to replace both systems. The furnace contains the blower motor that runs your air conditioning.

If your existing furnace does not have a variable-speed motor, your high efficiency AC (16+ SEER rating) will not be able to meet its potential energy savings.

When to Replace Both Systems

  • If your furnace is over 15 years old. Modern furnaces last 20-30 years, while central air systems typically only last 12-15 years. That means that your air conditioning will likely need to be replaced nearly twice as often as your furnace. If you are over halfway through the life of your furnace, it might make financial sense to replace both. You should not replace a furnace that is less than 10 years old because it will probably last until you need to replace your AC again.
  • If you want a high efficiency AC model. Anytime you want the full benefits of a high efficiency AC, you should consider replacing the pair. If you only want to install a typical AC unit with a SEER rating of around 14, it will likely not suffer as much from keeping the old furnace.
  • If your HVAC system is difficult to access. Sometimes it makes sense to replace both systems if installation is going to be particularly difficult and expensive. This could be because you live far away or because the system itself is difficult to reach due to placement. In these types of scenarios, discuss costs with the installer to see if it makes sense to replace both to save on future installation costs.

Meridian, ID Furnace Installation

Snowflake Air is your source for all of your heating and cooling needs, including furnace installation, in Meridian, ID and across Boise Metro.. We offer excellent customer service, same day visits, and competitive pricing.