Can I Replace the AC Unit Without Replacing the Furnace?

It’s one of the most common questions we get in the HVAC world and we hear it phrased in a lot of different ways. Basically, the question is, “Can I replace my outdoor unit without having to replace my indoor unit?”

No matter how you phrase it, the simple answer is… YES! If you have a gas furnace, then you can replace just your air conditioner. However, there are some key benefits to replacing both your AC and furnace at the same time.

Transparency and honesty are our entire mission at Watkins Heating & Cooling, so our service technicians will NEVER recommend replacement of your equipment unless it’s the best option for you.

Nearly everyone would prefer to replace just the one unit, because let’s face it, nobody wants to spend more money! Of course there are pros and cons to doing this. Below we explain when you should replace both units and when you should replace just one unit.

It’s important to note that this article only applies to those with a furnace that runs on natural gas, propane, or fuel oil. Gas furnaces make up the majority of households in our service area of Dayton and Cincinnati Ohio. If you have an electric furnace (electric air handler) and need to replace the AC/heat pump, then you will almost certainly need to do a full system replacement.

When to Replace Just the AC Unit

1. Your Furnace is Newer and Under Warranty

Our HVAC team sees it all the time where someone has an old outdoor unit on its last leg, but their indoor unit was just bought in the last few years. If your air conditioning unit is old and failing, but your gas furnace is newer, then replacing just the AC 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. Most technicians in the HVAC industry classify a “newer” unit as less than 5 years old, while units less than 10 years old are generally viewed as viable. 10 years is also the typical warranty period, so even if your newer unit is having issues, you can just get the individual parts fixed through the warranty and only have to pay for the labor and dispatch.

For instance, let’s say you have a 13-year-old AC unit with serious issues, but your furnace is only 7 years old and under warranty. In this case, it may make sense to only replace the air conditioner and get more life out of your existing furnace.

2. You Don’t Currently Have the Money

The main reason people are not eager to replace both their indoor unit and outdoor unit at the same time is that they simply don’t have the money for both expenses. If you’re on a strict budget or simply can’t afford replacing both units right now, it’s perfectly fine to just replace the one that urgently needs it. While replacing your AC and furnace separately will cost more in the long run, sometimes you have to make tough choices.

3. You’re Preparing to Sell Your Home

Are you getting ready to sell your home? If you’re preparing to sell your home in the next year or so, then it usually doesn’t make sense to replace both your AC and furnace unless they truly need it. As long as both units are less than 10 years old and still functioning well, that should be adequate enough for most homeowners to sell. Realtors and home buyers don’t typically place much more value on a 1-year-old air conditioning system over a 4-year-old air conditioning system, for example. Each of these still qualify as “newer.”

When to Replace Both the Air Conditioner and Furnace

1. Both Your Air Conditioner and Furnace Are Old

Air conditioners and furnaces over 10 years old are generally what the HVAC industry would classify as “older.” This is also when most indoor and outdoor units stop being under warranty. If both your AC and furnace are more than 10 years old, we would recommend replacing them both at the same time. Once your system hits that 10 year mark and is out of warranty, you will start to see repairs needed more and more frequently. By the time it reaches the 15-year mark, repairs become needed almost every year, and we definitely recommend looking into replacement.

2. To Save Money Doing Both

Labor is always going to be a sizable part of the price for replacing your outdoor unit and indoor unit. If you’re already planning on paying for a crew to come to your house and put in the work to replace the AC, then it often makes sense to just replace the furnace too. Replacing both units at once instead of doing them years apart is more cost effective, because you’re essentially paying for the labor and dispatch once instead of twice. This will save you hundreds of dollars in the long run.

3. Your HVAC System Setup Requires Removal

Sometimes our HVAC technicians encounter a job where it’s impossible to replace just the air conditioning without removing the entire system altogether. When that’s the case, you could save a lot of money in labor by having the workers replace both units while they’re already taken out.

The most common obstacle that requires full removal is your evaporator coil location. For example, in areas like our headquarters of Dayton, Ohio and Cincinnati, Ohio, we see a lot of concrete slab homes, where downflow furnaces sit on top of the evaporator coil. In order to change the evaporator coil, our crews must completely remove the existing furnace, change the coil, then re-install the furnace. In these cases, it may make sense to replace your furnace as well since most of the labor needed for that job is already done.

Another obstacle we see in some jobs is when your HVAC setup requires your water heater be removed in order to do the AC replacement. This setup can lead to time-consuming labor and a high-cost job, so if you have an older system, we would encourage replacing both units at this time. Paying a crew to remove the water heater today for your AC replacement and then having them come back a couple years later to remove the water heater for your furnace replacement will be at least hundreds of extra dollars.

4. For the Tax Credit

A lot of homeowners are hoping for money back from Uncle Sam when they get a new, energy efficient HVAC system. If you purchase a heating and cooling system that has a SEER2 (Seasonal Energy Efficiency Ratio) rating of 16 or higher (and 12 EER2), then you can earn up to $1,200 in tax credits. However, the only way you can get that full tax credit for your new system is if you get both a new air conditioner and furnace together. You could replace just your furnace for an energy efficient model and get up to a $600 tax rebate, but you will not be eligible for any tax credit if you only replace the air conditioner. The reason for this is that it’s impossible to give an accurate energy efficiency certification for a system with a new air conditioning unit and an older furnace.

5. You Want New, High-Efficiency Technology

If you are one of those people looking for the top technology or the best energy efficiency, you may need to look into a whole new system. Many of the new, highest-efficiency AC units do not work with other brands. Basically, getting one unit individually limits the quality of system you can buy. The most efficient air conditioners with a rating over 17 SEER2 are only compatible with the same brand of new furnace. This high-tech equipment requires seamless communication across the thermostat, furnace and air conditioner.

The benefit of moving to this kind of high-performance system is both the cutting edge technology and the savings on your energy bill. Let’s say you currently have an outdated furnace with a SEER rating below 10, for example. This old unit is likely causing you expensive energy bills and exchanging it for one of those new, high-efficiency systems will save you money down the road.

6. To Avoid the Cycle of Frequent Replacements

One frustration we see when people don’t replace both units at once is getting stuck in a cycle of replacing half the system every few years. Let’s say your furnace is 14 years old and needs replaced but you have a 7-year-old AC. You don’t want to replace the AC because it still has 3 years left on the warranty, so you just do the furnace. 7 years later, your AC is 14 and needs replacing. This time you decide to only replace the outside unit because the indoor unit still has 3 years left on the warranty. This is a prime example of how you can get stuck in a cycle of swapping out half the system every 7 years, instead of swapping out the whole system every 14.

How Much Will It Cost to Replace Both the Air Conditioner and Furnace?

Obviously the price of new furnaces and air conditioners are going to vary greatly depending on whether you purchase a new, high-efficiency model or older base model and factors like the difficulty of the installation job. But below are price estimates for outdoor units and indoor units to help you better make your decision:

How Much to Replace Just the Air Conditioner

The cost of just replacing just your air conditioner is around $4,000 – $7,000.

How Much to Replace Just the Furnace

The cost of just replacing just your furnace is around $3,500 – $6,500. Very similar to the cost of an air conditioner.

How Much to Replace Both Units Separately

The cost of replacing both your air conditioner and furnace separately is around $7,500 – $13,500.

How Much to Replace Both Units at the Same Time

The cost of replacing both your air conditioner and furnace at the same time is around $6,500 – $12,500. You will save about $750 – $1,000 by replacing them both together, rather than doing them separately. This is because you are essentially paying for the work crew dispatch and labor once instead of twice.

Note that the price estimates above could be slightly higher if you opt for the new, highest-efficiency models which are only available if you replace the whole system.

Your Final Decision

We’re here to help you make your final decision about whether to replace just your outdoor unit or to replace your indoor unit as well. There is one simple answer to the big question, “Can I replace just my air conditioner without replacing my furnace?” Yes, you absolutely can replace just your AC. But there are some major benefits to replacing your furnace at the same time. Here is a quick guide to help you make that choice –

When You Should Replace Just Your Outdoor AC Unit:

• If your furnace is newer (less than 5 or even 10 years old)
• If you simply don’t have the funds to pay for both units
• If you are preparing to sell your home

When You Should Replace Both Your Outdoor and Indoor Units:

• If your AC and furnace are both older (more than 10 years old)
• If you want to save money doing both
• If your system setup requires removal
• If you want the tax credit
• If you want new, high-efficiency technology
• If you want to avoid frequent replacements

The first step in your journey forward is to have an HVAC contractor like Watkins Heating & Cooling conduct a consultation of your HVAC system and determine the right solution for you, because everyone’s equipment and setup is different!

Then we send out a qualified HVAC technician to do a full service assessment of your heating system and cooling system and pinpoint exactly what is happening, what each of your options are, and the pros and cons of your different choices.

As we stated earlier, transparency is our number one goal at Watkins, so we will only ever recommend replacing your system if it’s the absolute best choice in your situation.

If you live in the Dayton, Ohio or Cincinnati, Ohio area, and want to figure out if you should replace your air conditioner or furnace or if you just need a simple repair, reach out to our transparent team of experts below. We’re always here for you.

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