Should I replace my furnace and air conditioner at the same time?

It happened. Your air conditioner just bit the dust. Now it needs to be replaced. Should you replace the furnace while you’re at it? Is it best to stagger these replacements, or install both new systems at the same time?

In most instances we recommend you replace them both at the same time. However, there are occasions when just replacing one unit is the better way to go.

As a general rule, your furnace will outlive your air conditioner. The average lifespan of a furnace is 15 to 25 years, while the average lifespan of an air conditioner is 10 to 15 years. If you have a gas furnace, then you can replace just your air conditioner. If your furnace will outlive your air conditioner, why should you replace them at the same time?

There are some key benefits to replacing both your air conditioner and furnace at the same time.

While your furnace and air conditioning systems operate independently, there are several common components to both systems. Serving as the control center, the thermostat monitors the indoor temperature and activates both the furnace and the air conditioning system to maintain your desired temperature. Both the furnace and the air conditioner depend upon the same furnace blower to move cool or warm air through the ducts. The vents and ducts in your house are used to move both the warm air from the furnace and the cool air from the air conditioner.

Once your air conditioner or furnace reach 10 years of age, they are generally no longer under warranty. If both your air conditioner and furnace are more than 10 years old, we normally recommend replacing them both at the same time.

If you replace one unit but not the other, your system is considered mismatched. If you invest in a new air conditioning system, but don’t install a new furnace, the energy savings you achieve will be limited because the system is using an older blower. When new equipment is appropriately matched, your whole system runs more efficiently. The improved efficiency can result in greater energy savings that will help offset its higher upfront cost.

Equipment compatibility can become a concern if you upgrade to a variable-capacity or two-stage air conditioner. A variable-capacity air conditioner can adjust its output to better maintain the temperature in your home. This can cut down on energy costs, temperature spikes, and hot and cold spots. If you don’t have a variable-speed blower motor on the furnace, a variable-capacity air conditioner won’t be able to reach its full potential due to incompatibility.

Many of the highest-efficiency air conditioning systems available today do not work with older systems or other brands. The most efficient air conditioners with a rating over 17 SEER2 are only compatible with the same brand of new furnace. Most of the newer high-tech equipment requires seamless communication across the thermostat, furnace and air conditioner.

When replacing both systems at the same time, we can ensure that the new furnace and air conditioner are designed to work together, optimizing their performance.

Labor is always going to be a sizable portion of the price you pay to replace an air conditioning system. If you’re already having a crew coming to your house to replace the air conditioning system, then it often makes sense to replace the furnace at the same time.

Occasionally, we encounter a job where it’s impossible to replace just the air conditioning without removing the entire system. When that’s the case, you could save a significant amount by having both systems replaced at the same time.

One example is if you have a downflow furnace that is sitting on top of your air conditioner evaporator coil. In order to change the evaporator coil, we must completely remove the existing furnace, change the coil, then re-install the furnace. In this case, it may make sense to also replace your furnace as it is already completely removed.

Another situation is when you have a small mechanical room and the water heater needs to be removed in order to perform the air conditioner replacement. Paying a crew to remove and reinstall the water heater today for your air conditioner replacement and then having them come back a couple years later to remove and reinstall the water heater again for your furnace replacement will cost quite a bit more than just performing the entire job now.

Perhaps you’ve renovated your living space but decided to keep the same furnace and air conditioning system. Even if there’s nothing wrong with your units, you’ll want to be sure they can still heat and cool the new space adequately. Not having the correct sized equipment forces your HVAC system to work harder, wasting energy, shortening its life span, and causing frequent issues.

When does it make sense to replace them separately?

Even though there are many reasons to replace your air conditioning system and furnace at the same time there are situations when replacing just one system may be the better choice.

If your air conditioning unit is old and failing, but your gas furnace is newer, then replacing just the air conditioning system may be the right choice! The age of your heating system and cooling system is one of the most important things to consider when making your overall decision.

You might have a 14-year-old air conditioning system needing expensive repairs, but your furnace is only 7 years old and still under warranty. In this case, it may make sense to just replace the air conditioner and get more life out of your existing furnace.

The main reason people are not eager to replace both their furnace and air conditioning system at the same time is that they simply don’t have the money to replace both systems right now.  In many cases it is possible to just replace the one system that urgently needs it. While replacing your air conditioning and furnace separately will cost more, sometimes, this is the decision that must be made.

Are you getting ready to sell your home? If you’re preparing to sell your home in the next year or so, then it may not make sense to replace both your air conditioner and furnace unless they absolutely need it. As long as both units are less than 10 years old and both still function adequately, that may be good enough to get the home sold.

If you are still unsure whether you need to replace both your furnace and air conditioner at the same time, contact us to schedule an in-home consultation. We’ll take a look at your current equipment and give you our opinion to help you with your decision.