New and improved

These units are surprisingly reliable. This, too, is designed into the units, because many of these outdoor units are placed on a wall many stories higher than the longest ladder.

Size and noise design considerations, though, are hardly new. Introduced to the U.S. market not 20 years ago, mini-split technology has not stopped advancing.

A few years back, many manufacturers started to put the metering device in the condensing unit housing. This boosted efficiency and maintained performance.

Although this design also eliminated the need for more than 50% of the standard refrigerant charge in the system, it is not without constraints.

Typically, line set length and elevation differences are shortened. For the rest of the world, this has not posed any difficulty because most of the time, the indoor and outdoor units are close together.

Instead of locating the outdoor unit on a four-story roof for a first-floor installation, the quiet outdoor unit is conveniently hung on the outside wall, near the indoor unit.

Heat exchangers have also continued to improve. Mini-splits have applied larger-than-typical heat exchangers for years. Not only does that equate to improved efficiency, but also to quiet operation.

Samsung specifics

Samsung employs several features that further enhance its heat exchangers.

All of its lanced fin-and-tube coils have rifled interior tube walls. When matched with the dense fin arrangement, the ambient air quickly changes temperature.

The indoor coil with this design extracts moisture quite efficiently, allowing the consumer to adjust the temperature setting at a higher level while enjoying the comfort of drier air.

Another innovation incorporated into these heat exchangers is in the fin coating. These coatings are actually films that adhere to the flat surface of the aluminum sheeting. Although they add considerable life to the heat exchanger, the purpose of the film is to aid in heat transfer.

The blue-tinged outside film reacts to moisture in the air. This transudation allows improved heat transfer.

The indoor heat exchanger film also includes an antibacterial formula that prevents fungi, molds, and bacteria from adhering to the coil. This feature helps keep the coil cleaner and minimizes odors.

Additional improvements have been made in the construction:

Exterior cabinets are sturdy, with each cabinet section having sharp creases to remain rigid and tight fitting.

A thick, poly-resin coating resists scratching and rust over the treated steel.

Rubber “socks” on the legs stabilize the unit.

Every compressor is wrapped with sound insulation and mounted on rubber bushings.

And, the condenser fan motor operates at a slow speed to quietly move the air through the large heat exchanger.

As I said before, the hvac industry constantly requires product innovations. So, even though the unit improvements listed here will take us into the 21st century, expect still more enhancements in years to come.