The short answer is yes, both indoor and outdoor units must be replaced at the same time. Of course, you can replace the outdoor unit and keep the indoor air handler or vice versa, but is it practical to do so? No, it isn’t. Any professional HVAC technician worth his salt will advise you to replace both so you can reap the benefits of a new system. That includes efficiency, savings, comfortable and quality indoor air.
Some homeowners don’t want to replace both indoor or outdoor units unless they are both not working. We get it―why fix what is not broken, right?
Well, we all want to save where we can, but when it comes to your heating and cooling system at home, you have to be smart about your decisions or suffer terrible consequences sooner or later. By “consequences” we mean insufficient cool airflow and spending more than you intend to in the long run.
Imagine replacing the outdoor unit first only to replace the indoor unit in a couple of months. You’re looking at two installation fees right there, not really the cost-effective approach you want. Or what if your AC will break down in the middle of summer and there’s no HVAC technician to service your unit? That’s a total inconvenience, especially if you live anywhere in Arizona.
Here are more reasons to consider when replacing your outdoor and indoor unit at the same time:
1. Older AC systems are not compatible with modern ones.
Newer air conditioning systems are fitted with the latest technology so they are often incompatible with older systems. It doesn’t make sense to modify an old unit to make it work with a new one. Sometimes, modifications are impossible at all or they cost more effort and money.
For instance, since 2016, the minimum Seasonal Energy Efficiency Ratio (SEER) is 14. Older air conditioning models that do not meet that rating are not compatible with anything sold in the market today.
There’s no workaround to fix AC SEER incompatibility. The same goes when refrigerants are incompatible. Since 2010, Freon or R22 has been forbidden by environmental standards due to its harmful ozone effects.
If your air conditioner runs on R22, Freon is still available and technicians can service your unit in case of refrigerant leaks. However, when you buy a new air conditioning unit, you can’t purchase one that works on Freon. Nowadays, refrigerants run on R-410A or Puron, a trademark of Carrier.
2. Matched systems are more efficient.
Outdoor and indoor units are designed to match to generate the best heating or air conditioning performance. So while replacing one and keeping another will work, the system won’t operate the way it was designed to and won’t deliver the same results.
Imagine changing the outdoor unit but keeping a leaky duct system. It doesn’t make sense at all. In fact, the older system will eventually cause the new system undue stress and wear it out faster.
3. Matched systems make the most of technology
Advances in HVAC technology have been mind-blowing over the last couple of decades. Variable-speed blower motors are now the range while single-speed ones have taken a backseat.
Thermostats are now smarter than ever, so much so that, aside from controlling indoor temperatures, you can integrate them with many smart home functions that operate on voice commands, like Amazon Alexa and Apple HomeKit.
These are just two examples of the new technology that you can take advantage of when upgrading your HVAC system. An older system will not be compatible with most new developments, at least its performance won’t be as efficient.
4. Mismatched units void manufacturers warranty.
A manufacturer’s warranty is provided under the assumption that both indoor and outdoor units are new. After all, manufacturers and HVAC professionals are well aware that a system is compromised and prone to damages when one unit is older.
A manufacturer will not honor the warranty of the newly installed outdoor unit. That’s a major disadvantage to you because, without a warranty, labor costs and parts will be heavier on your pocket. In essence, all that “saving money where you can” goes out the window the moment you lose the warranty.
5. Professional HVAC technicians don’t service mismatched units.
No HVAC professional will touch a mismatched system because doing so means a liability to them. They know no amount of fixing will ever get a mismatched system to work efficiently. Eventually, it will break down and the pro wouldn’t want to be held liable.
This leaves you no option but to hire a neighborhood repairman or, worse, a fly-by-night contractor. Unfortunately, those options don’t give customers a warranty. In fact, you may have a hard time contacting them again should you need a follow-up service. That means you need to get another person to fix a problem you already paid for.
6. Mismatched systems have shorter lifespans.
The outdoor and indoor units are designed to work together seamlessly. They complement each other to give you the heating or cooling you need to make your home safe and comfortable.
When only one unit is replaced, the other has to work harder to keep up with the new installation. Conversely, the new unit will not reach its peak performance and expected lifespan. The old unit will pull its efficiency down, and the additional pressure will stress the new unit so that it consumes more electrical energy and increases utility bills.
7. Mismatched systems reduce real estate value.
When a house is listed on the market, a home inspection is performed to help protect potential buyers. One of the major highlights of every home inspection is the quality of the HVAC system in the house.
Essentially, a mismatched indoor and outdoor unit is more of a liability, not an asset or a benefit to the potential homeowner, and will be identified as such by the home inspector.
Unfortunately, if it were your house, the mismatched system will affect its value and may even turn off potential buyers.