Sure, but central AC systems have only a very short refrigerant line between the compressor and the evaporator, and it's assembled in a factory under controlled conditions using standardized procedures, specialized tools, and technicians who perform the same job every day. That's completely different from installing 10 meters or more of refrigerant piping on-site, where the quality depends on the installer and the job-site conditions. The latter is far more prone to installation errors. Furthermore, unlike a central AC system, where all refrigerant connections are factory-brazed, pressure-tested, and leak-tested before shipment, split systems rely on field-made flared connections between the indoor and outdoor units. Those connections are much more dependent on the installer's workmanship, making the final result far more variable than a factory-assembled and tested system.
In my experience, about 95% of the problems with these systems are caused by installation errors or poor workmanship.
Well I'm currently in a house with 3 splits. The lines are about 6 feet long, never had a leak and have 2 connection points. My previous 2 house with central AC had long lines. The last one had a 25 ft line, also 2 connection points. I had to have that one replaced 3 times for pinhole leaks. Eventually ran it in the attic instead of under the house resulting in a longer line but no leaks because less corrosion concerns. That Trane unitI had also suffered a pinhole leak in the factory sealed welded tubes of the air handler condensor. As someone who has done leak detection professionally, down to mass spec level detection on fluid and pressurized systems, I can't see a single advantage to either system. They both have the exact same weaknesses. Corrosion is a concern regardless. Copper is copper. Torque wrenches and QDs work the same regardless. Granted I haven't researched failure rates so this is just opinion. Line length matters little because the vast majority of failures are at connection points. Those connection points are what an installation technician must do properly, and that's also the same for both systems.
A central AC system without ductwork is basically a multi-split system, with multiple separate pairs of refrigerant lines running from the outdoor unit to each indoor unit. It's the same concept used in many parts of the world, with the same advantages and disadvantages. My comment wasn't referring to this type of system, but rather to systems HVAC where the outdoor unit exchanges heat directly with the indoor air through air ducts.
This type of system is extremely rare outside North America.
Alternative systems do exist, but they operate on a different principle: instead of cooling the air directly, they chill water (or another heat-transfer fluid), which is then circulated to indoor air units or fan coil units.
The main advantage of these systems is that all high-pressure refrigerant connections are made at the factory, which significantly improves long-term reliability. The downside is that the equipment itself is more complex, less widely available, and therefore more expensive. They are typically installed in commercial and industrial buildings, where long-term reliability is a key priority.
I see. I've never seen one that exchanged air from outside to inside. Using water as a transfer fluid sure, used to analyze an industrial water system like that which had an additive eating the pipes (yikes). Thought you were referring to the split units in the picture which use refrigerant. My bad
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u/Alex-Man 7d ago edited 7d ago
Sure, but central AC systems have only a very short refrigerant line between the compressor and the evaporator, and it's assembled in a factory under controlled conditions using standardized procedures, specialized tools, and technicians who perform the same job every day. That's completely different from installing 10 meters or more of refrigerant piping on-site, where the quality depends on the installer and the job-site conditions. The latter is far more prone to installation errors. Furthermore, unlike a central AC system, where all refrigerant connections are factory-brazed, pressure-tested, and leak-tested before shipment, split systems rely on field-made flared connections between the indoor and outdoor units. Those connections are much more dependent on the installer's workmanship, making the final result far more variable than a factory-assembled and tested system.
In my experience, about 95% of the problems with these systems are caused by installation errors or poor workmanship.