Mini Splits/Ductless Systems: How Do They Work?

Young woman switching on air conditioner while sitting in armchair at home.

There are a lot of applications for which a ductless system can be used in Carbon Valley. Mini split systems can be used for alleviating a hot or cold spot, helping heat and cool a renovation or new construction, and even providing comfort for light commercial use.

With many types of installation options available, there aren’t many situations that a ductless system can’t help with.

Ductless mini splits are a great option when you are remodeling or planning to add an addition to your Longmont home. Give Carbon Valley Heating and Air a call today for a free consultation on how a ductless system can enhance your comfort.

What Is a Ductless System?

Mini split systems have two main components: an outdoor condensing unit and an indoor air handling unit. The link between the two units is called the conduit; it houses the power cable, refrigerant tubing, suction tubing, and condensate drain.

Ductless systems are available where no ductwork is needed, while ducted mini splits can use little ductwork in the ceiling or below the floor. The unit or units will operate to reach the temperature set on either the thermostat or remote control. Some models can be controlled via a smart device as well.

Mini Split Models

With many different application types and installation options, there are a lot of options available:

Outdoor Units

Single-Zoned Cooling Only: designed to provide a high comfort level to a single room for cooling purposes only while being energy efficient (up to 24.6 SEER) and very quiet (as low as 48 dB).

Single-Zoned Cooling and Heating (Heat Pump): designed to provide a high comfort level to a single room for cooling and heating purposes year-round. Some models are designed to provide outstanding heating performance even in extreme cold. Models can be energy efficient (up to 42 SEER & 15 HSPF), quiet (as low as 47 dB).

Multi-Zoned Cooling and Heating (Heat Pump): designed for whole building comfort for cooling and heating purposes.  One outdoor unit can support up to 5 indoor units, and each zone can be individually controlled to meet personal comfort needs. Units can be energy efficient (up to 23.8 SEER & 12 HSPF) and quiet (as low as 49 dB).

Indoor Units

Wall Mounted: designed to provide cooling and heating to an individual room while monitoring room conditions and self-adjusting the fan for ideal personal comfort. Units can be very energy efficient (up to 33.1 SEER & 13.5 HSPF), quiet (as low as 19 dB), cooling only, and available in 3-speed or 5-speed fan speeds.

Horizontal Ducted: designed to use ductwork that can be concealed in the ceiling or below the floor. Ideal for new construction or renovations. Units can be energy efficient (up to 19.6 SEER and 12.1 HSPF), quiet (as low as 23 dB), and 3 fan speeds.

Ceiling Cassette: designed to fit between standard 16-inch joists to provide cooling and heating to one area.  Great option for renovations, new construction, and light commercial. Units can be energy efficient with SEER Ratings up to 19.6 and HSPF up to 12.1 while being quiet with Db levels as low as 24 and 3 fan speeds.

Floor Mounted: designed to fit in rooms with little vertical wall height where a wall unit or ceiling unit will not fit to provide a room with cooling and heating.  Units can be energy efficient with up to 28.2 SEER and up to 13.6 HSPF while being quiet with a dB rating as low as 21 and 5 fan speeds.

Ducted Air Handler: designed to accommodate new construction, renovations, replacements, and light commercial to provide heating and cooling through ductwork. It can be installed vertically or horizontally.  It can be broken down to fit through tight access points and reassembled.  Units can be energy efficient with SEER ratings up to 21.4 and HSPF up to 10.4 while being quiet with dB levels as low as 27 and 3 fan speeds.


Mini split systems are designed to offer cooling and heating to rooms or areas to provide comfort to occupants. Designed to be energy efficient, easy to install, quiet, and easily adjustable to provide year-round comfort to make your living space comfortable and what you want it to be.


Indoor Air Quality (IAQ): ductless mini splits are designed to treat the air in the area in which it is installed. Filters are installed on all indoor units, and some models can capture and remove allergens, odors, and other contaminants to make your air clean and keep you healthy.

Extreme Low-Temperature Heating: some models are designed to provide comfortable indoor temperatures even during the coldest days (as low as -13 degrees Fahrenheit).

Quiet: without ductwork or with little ductwork, mini split systems are designed to deliver cooling and heating directly to the rooms they are intended to serve, which means there is no need for fans, keeping the noise down, outdoor units as low as 48 dB and indoor units as low as 19 dB.

SEER2 (Seasonal Energy Efficiency Rating 2)

SEER2 is a ratio of the amount of cooling produced (BTU) divided by the amount of electricity (watts) used. The difference between SEER2 and EER is that SEER2 accounts for changes in outside temperature instead of just one temperature. EER should be used as a comparison when the outside temperature is consistently over 95 degrees Fahrenheit.

The higher the SEER2, the greater the heat pump’s efficiency could be. Generally, most single-stage heat pumps rate from 14 to 16 SEER2. Two-stage units rate from 17 to 19. Variable speed units rate from 18 to 21.

HSPF (High Seasonal Performance Factor)

Represents the total heating output of a heat pump (including supplementary electric heat) during the normal heating season (in Btu) as compared to the total electricity consumed (in watt-hours) during the same period.


With normal maintenance and care, mini split systems can last over 20 years. Make sure to keep the filters and coils clean. Make sure the outdoor unit is free from obstruction, and the unit is free of debris. Check the drain pan to ensure it stays clear of moisture. Inspect the refrigerant lines, visually confirming the lines are insulated and not damaged.

Quality HVAC Services in the Carbon Valley

Our experienced technicians can help you maintain the service life of the ductless mini split by performing an HCPP check on your mini split.

Some checks the technician will perform are refrigerant levels, ensuring the coils are clean, checking the drain pan, checking the entire outdoor unit, inspecting the refrigerant lines, and ensuring the units are set to the manufacturer’s specifications.

Learn More Heating and Cooling Tips for Your Home

Schedule a free consultation with Carbon Valley Heating and Air to find out more about ductless mini splits and other comfort features for your Longmont, CA, home. Call us today at 720-383-7911 or request service online.

Need HVAC Service?

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Call us at 303-833-4466!