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Ductless Mini Splits: 4 Things You Should Know About

Ductless mini splits are receiving well deserved attention for providing versatile and energy efficient heating and cooling solutions for a multitude of applications. What you may not know are the four technological advantages, and advances, that are driving ductless systems'  efficiency, quality air conditioning and widespread popularity.

Ductless Mini Splits Basics

Ductless mini splits are manufactured to conform to a myriad of design specifications for remodels, space conversions and existing spaces (zones) in the home. Utilizing versatile and compact components, ductless systems are point-of-use heat pumps and cooling units that operate by the same refrigeration principles as central heat pumps and A/Cs, but do not require air ducts for distributing heating and cooling.

Instead, ductless mini splits are refrigerant distribution systems, made possible by a thin and flexible conduit that houses refrigerant and power lines extending from the outdoor cabinet to small point-of-use air handling-units (AHUs). 

Custom Comfort Solutions

Central systems employ one large heat-exchange coil that heats and cools airflow to extreme temperatures to compensate for heat energy losses as it flows through the air ducts. Since ductless mini splits are point-of-use systems, and don’t need to compensate for energy losses, the indoor AHU is much more compact and versatile, allowing for multiple mounting options that are practically custom-designed to interior spaces.

These are the primary mounting options of the indoor AHUs:

  • High wall mounting is a popular and straightforward installation that mounts the AHU high on an interior wall. The components housed inside the stylish cabinet are easily accessible for cleaning.
  • Low wall mounting is another mounting option that leaves space for vacuuming beneath the cabinet. It may be more suitable in some interior designs than high wall mounting, since it may blend in with furniture and not draw attention.
  • Ceiling mounted AHUs are sleek and out of the way of foot traffic. Airflow enhancements provide nice room conditioning for more even heating and cooling. (High wall, low wall and ceiling mounted installations are also referred to as universal mounting options.)
  • Concealed mini duct installation hides the AHU in the ceiling, wall or floor completely out of sight. A short duct run connects the AHU to air supply and return grilles. A concealed mini duct installation has the same look and feel of a conventional installation, but without the noisy air ducts. The mini duct delivers quiet and smooth airflow.
  • Ceiling suspended AHUs are concealed above the ceiling panel of a drop ceiling. These are excellent mounting options for office and commercial applications.

The outdoor cabinet houses the compressor, a second heat exchange coil and fan. The footprint of the cabinet is significantly smaller than a conventional system, requiring only a small concrete slab for mounting. You may also use mounting brackets to attach the cabinet to the exterior wall of the home. The cabinet may be veiled by landscaping for better aesthetics and inconspicuous installation. 

Keep these tips in mind when designing the mounting option:

  • Allow for no less than four feet of unobstructed space to the sides and top of the cabinet. This permits free airflow to the heat exchange coil, which is essential for refrigeration systems.
  • A shaded location is better than a sunny location.
  • If snow accumulation is a concern around the cabinet, consider the exterior wall mounting option.
  • The cabinet should be more than six feet away from venting of other combustion home appliances, such as furnace sidewall venting or a gas dryer. While the venting has no effect on the mini split's components, you don't want to disrupt venting with the cabinet’s fan.
  • You may install a protective covering above the cabinet to help protect it from ice and freezing rain. However, there should still be three or four feet of clearance between the cabinet and covering.

The thin conduit that connects the outdoor cabinet to the indoor AHUs only requires a 3-inch hole through the home’s exterior wall. It’s important that your HVAC professional knows how to handle the conduit for safe installation. The conduit provides insulation and protection for the refrigerant lines, condensate line and power cable. If it's damaged, water could leak inside your home.

Zoned Temperature Control

Ductless mini splits offer great versatility for a host of heating and cooling possibilities because that’s the purpose for which they were designed in Japan in the 1970s. A premium was, and still is, placed on home and office square footage, and bulky air ducts took up too much valuable space without being efficient. Window units were noisy and disruptive to home serenity and workplace activities, were inefficient, and blocked sunlight.

Ductless systems combined, and improved upon, the easy installation of window and portable units with the more powerful heating and cooling capabilities of conventional systems. Utilizing refrigerant distribution heating and cooling, ductless mini splits opened up a plethora of design options for conditioning one zone, multiple zones and entire homes and offices. These are the choices for zoned temperature control:

  • Single-zoned are the original ductless mini splits, consisting of one AHU for spot or room heating and cooling. Mini splits are ideal for converted spaces, new additions and supplemental conditioning.
  • Multiple-zoned ductless systems utilize an outside condensing/compressor unit that's designed to link to two or more indoor air handling unit. Each AHU offers independent temperature control for a genuine zoning system. For instance, you could install one AHU in a converted attic space bedroom, add another AHU to a downstairs home office to heat and cool independently (rather than the entire home), and connect both AHUs to one outside cabinet.
  • Modular-zoned ductless systems link multiple outdoor cabinets to several indoor AHUs for whole-home heating and cooling solution. These are excellent for new home design, whole system replacements, and for older homes that were not constructed with air ducts.

Super-Heating, Super-Cooling, Super Savings

One of the most productive and valuable technological innovations in ductless mini splits is the implementation of inverter-driven compressors. This technology delivers variable-speed output for preparing and delivering precise amounts of refrigerant required to meet real-time heating and cooling demand at each indoor AHU. 

Inverter-driven compressors use substantially less electricity than conventional single-stage (one speed) compressors. They also offer much quieter operation than their larger counterparts – producing only about half the noise of the quietest high-efficiency heat pumps and A/Cs.

Moreover, high-efficiency ductless mini splits (and multi splits) utilize ozone-safe refrigerant (Puron), which operates under much higher pressures than the old R-22 (Freon). The delivers super-heating and super-cooling capabilities unmatched by systems past.

These are the benefits to homeowners of ductless technology combining inverter-driven compressors and high-capacity refrigerant:

  • Continuous comfort is maintained by maintaining output at the thermostat setting,  with none of the quick cycling of large conventional systems. Instead, ductless mini splits deliver smooth, quiet, efficient and comfortable heating and cooling.
  • Initial startup at low speeds uses less energy than conventional systems powering on at full throttle.
  • Inverter-driven compressors quickly ramp up, if needed, for quick and powerful heating and cooling. Once the desired temperature is reached, the variable-speed and output ramp down for continuous comfort (and continuous savings).

Featuring Convenience, Air Quality and Efficiency

Ductless mini splits can be easily misunderstood. Though they are small in size, installation and energy consumption, they are powerful point-of-use systems that deliver precise heating and cooling wherever and whenever needed.

Another advantage of a point-of-use heating and cooling system is that the indoor AHUs are sized specifically to the zone to be heated and cooled. This saves money on system cost (many conventional systems are over-sized, which increases initial investment costs), operation, and maintenance and repairs. Plus, you will enjoy quiet comfort that is friendly to your pocketbook.

More benefits for convenience, quality and efficiency include:

  • The AHU offers advanced air purification and filtration components. Airborne contaminants, such as viruses, allergens and mold spores, and odors of all sorts are removed from the zone. The filters are easily removed from the cabinet, and are washable and reusable.
  • Wireless hand-held comfort controls are standard. Use 24-hour timers and programming for convenience and energy savings.
  • Ductless maintenance is simple, requiring professional service by a reputable HVAC contractor once a year (the same as conventional systems); easy do-it-yourself filter cleaning; and clearing obstructions and debris to maintain free airflow at the outdoor cabinet. Keep an eye on snow and ice accumulation during the heating months, and leaves, grass clippings and other debris during the other seasons.
  • The indoor heat exchange coil is generally accessible on most units. It may be wiped on occasion to remove any debris that hinders heat exchange. Or save this task for your HVAC pro, who also will treat the drainage system to prevent algae, bacteria and other contaminants from growing.

For more information about ductless mini splits, please contact us at Comfort24-7.com to speak with a certified HVAC contractor who's experienced with ductless systems, near your home in Chicagoland, northwest Indiana or southwest Michigan.

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