Residential & Commercial Service and Repair


Ductless Mini Split Heat Pump F.A.Q

Harmonic is your local Oswego ductless mini split expert. Ductless mini splits are highly efficient comfort systems that are great at both cooling and heating your home here in the Naperville and St. Charles area. We offer ductless mini split systems from Mitsubishi for new residential and commercial installations. If you need mini split repair, installation, or maintenance get in touch today!

Ductless Service

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What is a ductless mini split heat pump?


A ductless mini split is a highly efficient zoned refrigerant based heating and cooling system that does not require a central duct system. Most of our customers take advantage of these systems for their highly efficient cooling capacities. A ductless mini split heat pump has an outdoor unit and one or more indoor units with a refrigerant lineset and wiring harness connection between them. The indoor units are most commonly very compact and are mounted 6 - 8' above the floor of an indoor space, and deliver heated or cooled air directly to the conditioned space in which it is located.


How does a ductless mini split heat pump work?


Ductless heat pumps are a refrigerant based HVAC solution. They utilize electricity and a compressor based system to move thermal energy from outdoor air into you home in the winter, and extract heat from indoor air and expel it outdoors in the summer. These systems are fantastic at cooling zones within your needed space during the high summer heat here in the Oswego, IL area. All modern ductless heat pumps utilize variable speed technology which makes them more efficient and more comfortable to live with.


What are the common components of a ductless heat pump system?


Outdoor unit:

  • Inverter Compressor: Traditional HVAC compressors are on or off. The compressor is off or its running at 100 percent. Inverter compressor always running in the background, adjusting the compressor speed in real time. By ramping up and down as needed an inverter provides a more accurate, on-demand approach to temperature control. The variable speed DC current drive operates much more efficiently than a traditional AC compressor.
  • Condensing fan motor: Fan motors move air across the outdoor coil to facilitate thermal transfer. Mini split heat pumps utilize efficient variable speed fan motors that improve performance through a wide ambient operating temperature range.
  • Reversing valve: A ductless heat pump reverses its refrigerant flow from summer to winter. Modern reversing systems and smooth and reliable.
  • System defrost: During heating mode a defrost system may be initiated when the outdoor coil temperature falls below 32°F and the moisture in the air starts to freeze on the outdoor unit’s heat exchanger. Sensors in the outdoor unit detect that frost or ice has started forming. The indoor and outdoor fans will stop, and the compressor keeps running to melt accumulated ice.

Indoor Units: Each indoor unit comprises an HVAC zone that can be controlled independently.

  • With our primary line Mitsubishi, there can be from one to eight indoor units for a given outdoor unit. Traditional ductless indoor units unit are high wall, typically between 7.0 and 36.0 MBtuH, and are mounted about seven from from floor level. Other indoor units can be floor mounted, ceiling mounted, or are air handlers designed to be used with very short duct systems.
  • Indoor fan motors: Mini splits have ultra quiet DC drive variable speed motors for air flow flexibility and comfort.
  • Indoor controls: Traditionally ductless systems include a hand-held remote to control the operation of the indoor unit. There is also the option of wall mounted controls similar to traditional thermostats, or App based control via an Apple or Android mobile devices.
  • Lineset(s): Between the outdoor and indoor unit(s), a lineset is installed that contains two insulated copper tubes, along with a power / communication cable, and a condensation drain. This lineset is very compact and only requires a 3" diameter access-way.

  • How long will a ductless heat pump system last?


    With proper installation, and consistent maintenance, you heat pump system should last for 20 years or more.


    Do I still need my old cooling system, or a back-up system for hot weather?


    Our offered Mitsubishi ductless mini split heat pumps are highly efficient at cooling your needed space. Many of our residential customers already have central AC when they decide to install a ductless mini split, but often we hear that these systems are working so well at cooling the central AC's hardly have to be used! Sometimes our customers even see their electric bills go down after ductless heat pump installation because their central AC is not being used as much as before!


    What are the primary advantages of a ductless heat pump system?


    • Energy savings in both heating and cooling: with SEER ratings as high as 33.0, and heating HSPF to 12.5, ductless systems are much less expensive to operate than electric, oil, or LP gas systems. They are also the most efficient cooling system available in most applications.
    • Flexibility: With a broad range of sizes and configurations, you application can be configured to exactly meet your needs.
    • Space saving: There is no indoor mechanical space require for ductless systems, so that space typically devoted to a furnace or boiler, and ductwork, is not necessary.
    • Easy to install: ductless systems can be installed quickly. They do not require ductwork, and our 3" linesets can be typically run with a minimum amount of disruption.
    • System zoning: With ductless, zoning is simple. You can have accurate temperature control in you application for any zone you set-up.
    • Seasonal REBATES available at $500 from your utility company throughout specific months of the year
    ask us about available rebates

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