How Do Ductless Mini-Splits Work?

A ductless mini-split moves heat instead of making it. An outdoor heat pump connects to one or more indoor units through a small line set.

In summer it carries heat out of your home. In winter it pulls heat from the outdoor air and brings it inside. No ductwork is needed.

How a Ductless Mini-Split Works

A mini-split uses heat transfer: it moves thermal energy from one place to another. Refrigerant runs in a closed loop between the outdoor unit and the indoor units. Each indoor unit draws in room air, warms or cools it, and sends it back out at the temperature you set.

How a Mini-Split Heats and Cools Your Home

Heating

Even on a cold day there is some heat in the outdoor air. The cold refrigerant in the outdoor unit absorbs it, the compressor concentrates it, and the refrigerant carries that heat indoors to the indoor unit. Mitsubishi Hyper-Heat (H2i) models are rated to heat in outdoor temperatures as low as −13°F.

Cooling

In summer the process runs in reverse. The indoor unit absorbs heat from your room, and the refrigerant carries it outside, where the outdoor unit releases it. Read more: How Do Ductless Mini-Splits Dehumidify in the Summer?

The Parts of a Mini-Split

A mini-split is "split" between outdoor and indoor equipment.

Outdoor Unit (Heat Pump)

The outdoor unit handles the heat transfer. It looks like a central air conditioner condenser but is usually slimmer, with the fan on the side rather than the top.

Line Set

The line set connects the outdoor unit to each indoor unit through a small opening in the wall, about 3 inches. It bundles the refrigerant tubing, the power cable and the condensate drain inside a protective cover, so the outside of your home stays neat.

Indoor Unit (Air Handler)

Each indoor unit circulates the air in its room and has its own control, so you can set each room separately.

Types of Indoor Units

• High-wall units: slim units mounted high on the wall. They are good when you want the system out of the way or have a lot of furniture.
• Floor-mounted (low-wall) units: sit low on the wall near the floor, leaving the upper wall free.
• Ceiling cassettes: sit flush with the ceiling and suit larger rooms.
• Short ducted units: one indoor unit serves a few small neighboring rooms through short duct runs. Those rooms share one control.

Single-Zone vs Multi-Zone Systems

• Single-zone: one outdoor unit and one indoor unit for one room, such as a bonus room, a finished basement or a home office.
• Multi-zone: several indoor units on one outdoor unit, each room with its own control. The number of indoor units depends on the outdoor model. We size every system for your home.

Inverter Compressors and Controls

Mitsubishi's INVERTER-driven compressors change speed to match the heating or cooling the room needs, instead of switching fully on and off. Each indoor unit comes with its own remote. Mitsubishi also offers wall controls and a smartphone app option.

Do Mini-Splits Work in Pennsylvania Winters?

Mitsubishi Hyper-Heat (H2i) models are rated to heat in outdoor temperatures as low as −13°F. Sizing and placement matter, so we size and place each system for your home.

What Ductless Installation Involves

The indoor units mount on the wall or ceiling. The outdoor unit sits on a pad or wall bracket.

• The line set runs between them through a small opening.
• How long the job takes depends on the number of zones and your home. For the full process, see our page on ductless installation. For an overview, see Mitsubishi ductless mini-splits.

Ductless Installation in York County, PA

Air Comfort Technologies is a Mitsubishi Diamond Contractor rated 4.9 stars, 440+ Google reviews.

• Mitsubishi offers a 12-year parts and compressor limited warranty on qualifying residential systems installed by a Diamond Contractor and registered within 90 days, and we register it for you.
• Air Comfort adds a 5-year labor warranty on ductless installs.
• Estimates on new ductless systems are free.

Wondering about price? Read ductless mini-split cost in York, PA.

Call (717) 855-4101 or schedule a free estimate. Air Comfort Technologies · 208 Plaza Drive, Manchester, PA 17345 · PA HIC PA117750

Mitsubishi 12-year parts and compressor limited warranty requires installation in a single-family home by a Diamond Contractor and registration within 90 days; original owner residing in the home. See mitsubishicomfort.com for full terms.