Different Brands Of Indoor & Outdoor AC Units (Will This Work?)

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Everyone is aware of the two primary types of air conditioners on the market: split systems and single packaged units. Split system air conditioners currently account for about 70% of the market, as people prefer them to single packaged units. But when they inevitably break, can you fit another model or brand’s components to fix it, or will this not work? 

It is OK to replace components from different brands in Single Packaged units and economy-line split systems as long as they match. However, higher tier Split Systems do require most parts to brand match. Mismatch systems may be incompatible, lead to efficiency problems, and void your warranty. 

For almost ten years now, R-22 refrigerant has been banned because it is hazardous to the ozone. As a result, it is no longer manufactured or imported and has been replaced by 410A. However, many systems still use R-22 and are incompatible with 410A systems. For this and other reasons, mismatching brands could lead to issues. 

The Variance Between A Split System & Single Packaged Unit

Their design is the fundamental distinction between a packaged unit and a split system air conditioner. AC units in packaged and split systems work the same way. They extract heat from inside the building while expelling the heat extracted to the outside air.

There are six essential parts to the AC system:

  1. Condenser
  2. Compressor
  3. Evaporator coil
  4. Air handler/ furnace
  5. Copper tubing with refrigerant
  6. Thermostat

Single Packaged AC Units

The Single package type combines all of its components into a single unit, including the evaporator, condenser, thermostat, and compressor housed in a single metallic or plastic cabinet. There is generally a hole in the wall where this box resides, or the window units fit inside the window. They are loud and not very efficient compared to split systems. 

In most cases, using different brands’ components to fix these has no significant detrimental effects on single-packed units. The important part is to size the unit correctly and ensure that the coils, blower, and wiring are compatible.

Split System Type AC Unit

Someone installing an AC wall unit
Someone installing an AC wall unit

The split system type AC unit works differently from the single package type and comprises two distinct sections: an inside and outside unit. You will find the condenser unit mounted on the roof, outside wall, or ground. Fixed to an inside wall, you will find the air handler, also called the furnace. The air handler and the condenser units function separately, but pipes with refrigerant link them. 

Most manufacturers now offer Inverter technology in their split systems, making the air conditioning units more energy-efficient and extremely quiet. In addition, unlike packaged units, inverter split AC’s can handle voltage or current changes.

Ensured Effectiveness Through SEER

The Seasonal Energy Efficiency Ratio of a central air conditioner determines its efficiency (SEER). The air conditioner’s cooling output divided by the total energy consumption during an average year’s usage makes up the SEER rating. The higher the SEER rating of a central cooling system, the more efficient it is. All manufactured central air conditioners must have a minimum SEER of 13 as of 2006.

Warranties, Rebates, And Compatibility

Every year, the AC, Heating, and Refrigeration Institute (AHRI) tests thousands of indoor and outdoor systems to ensure they appropriately match. To see if a specific outdoor/indoor combination is compatible, ask the contractor who installs your AC for an AHRI Certificate of Certified Product Performance.

Alternatively, you can request an AC system’s Certified Reference Number and look it up in AHRI’s database online.

A utility rebate for installing a high-efficiency system in your house is another reason to ensure an AHRI Performance Certified matching system. Check with your local utility provider for refund restrictions; however, many will ask you to supply your system’s ARI Reference Number to receive a rebate.

However, because manufacturers (Brands) build their components to operate optimally together, there is the possibility of some efficiency loss when mixing and matching. Also, when replacing only one of the parts on a split system, keep in mind that you are also integrating parts of varying ages.

The level of wear in older systems will affect the new system. In addition, some manufacturers will not fulfill a warranty if only one system component gets replaced.

The Brands Of AC Units And Their Tier Levels 

Several large air conditioning (AC) units
Several large air conditioning (AC) units

There is a lot to consider in an HVAC (Heating, Ventilation, and Air Conditioning) system, like each brand’s quality and price. Is it a single package, duct, or ductless split unit? Single-stage, two-stage, variable speed, and even inverter-type systems have different SEER Values. 

Some brands have a higher quality tier level than others. They fall into three categories top tier (premium brands), mid-tier, and economy. There are also a few ductless brands that compete for market share. Let’s look into the different brands from each tier:

The Premium Lines

  • Lennox
  • Carrier (Carrier and Bryant, built and assembled in the same factory)
  • Trane (American Standard, also constructed and made in the same factory)

Mid-Tier Units

  • Bosch
  • Amana 
  • Day & Night
  • Heil
  • Rheem
  • Ruud

The Economy Lines

  • York
  • Coleman 
  • Goodman
  • Payne
  • Daikin
  • RunTru
  • Tempstar

There Are Also Other Ductless Mini-Split Systems

  • Midea
  • Mitsubishi
  • Gree
  • Fujitsu

Repair and Installation Standards

The same factory builds and assembles Trane and American Standard, just like Carrier and Bryant, where Rheem and Ruud are also called sister companies. Therefore the components of these units that come from the same factory should be interchangeable.

So, for example, the same high voltage contactor and furnace inducer motor found in a Carrier air conditioner should fit a Bryant air conditioner. 

The same must be valid for Trane and American Standard and Rheem and Ruud. Any AC system comes fully functional and assembled from the factory, ready to work; however, you should know that you require an experienced technician to install and modify it according to the manufacturer’s guidelines.    

Your system may last 5-20 years or more, but it comes down to the difference between a DIYer and someone specializing in installing these systems. The following is a list of things that need special care while installing to meet the safety code:

  • Water drainage
  • Thermostats
  • Blower settings
  • Gas piping
  • Gas pressures
  • A precision refrigerant charge and airflow
  • Static air pressures 
  • Intake air
  • Exhaust system
  • High and low voltage wiring 
  • Fuse sizes

Single-Stage Split Systems

The Single-Stage is the entry-level heating and cooling option for most brands. Almost every component of these single-stage systems is repairable with universal parts. Single-stage motors, compressors, control boards, pressure switches, and gas regulators are all parts of a single-stage unit, and most of these are interchangeable between brands. There is, therefore, no need for a distributor’s brand part.

Single-stage AC units are the most cost-effective solution but have the lowest quality and value. Running at 100% capacity when active, these systems also have the most vulnerabilities and are more prone to failure. However, as mentioned earlier, fixing these is easier to replace parts from almost any brand if it’s compatible and doesn’t leak.  

Two-Stage Split Systems

The technology in Two-Stage systems is superior. They are more efficient and control the temperature in your home with less fluctuation. The primary characteristic of a two-stage approach is that it usually operates at roughly 70% capacity in the first stage and 100% capacity in the second stage. These systems will mainly run in the first stage when zoned correctly, saving you money.

Two-stage unit parts are of higher quality, and there aren’t many universal parts for the two-stage systems. Capacitors, contactors, and a few other components are interchangeable. However, higher-end equipment has safety features such as special pressure switches to prevent the furnace or air conditioner from internal harm 

Any two-stage system will outperform a one-stage system. If the two-stage motors and compressors fail, you will order them from the manufacturer or warehouse. You should only order these components from the same or sister brand manufacturer.

Variable Speed Systems

An AC compressor unit
An AC compressor unit

A Variable Speed unit is the most efficient option. Variable speed systems can alter their capacity levels from around 25% to 100% in small increments at a time. They keep the temperature swings in the house even lower. These systems can keep your home within a half-degree of the desired temperature.

It is not advisable to fix these types with other brand components. Only their unique parts will be able to fit these variable speed devices. With such complex equipment comes a more significant learning curve for those who can repair for you. Trane, Lennox, Carrier, and other companies with variable speed lines like Bosch will sell these parts only to reputable dealers. 

There are also inverter-type systems, and handling inverter-type repairs and installations necessitate even more advanced skills on a different level compared to standard run-of-the-mill skills. 


Simply replacing one of your cooling system’s units may provide the lowest price, but it will not offer the best value. At best, the system will continue to function, but it will not meet the claimed energy efficiency levels or give you the amount of comfort cooling you anticipate. In the worst-case scenario, improperly matched indoor and outdoor units might put undue strain on your cooling system, leading to an avoidable, premature failure.

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About Charlie D Paige

Charlie is a massive DIY fan, with dozens of DIY projects under his belt - ranging from tiling to electrics, and concrete pads to walls. Charlie loves tinkering, seeing how things works, the outdoors and playing with power tools... so is it any wonder that he's completed so many DIY jobs over the years?

Charlie loves spreading his hard-won DIY experience with the world via this blog.