How Far Can You Run Mini Split Lines? (Solved)

If you don’t know how far mini-split lines run and how to select and install them properly, your heat pump and mini-split won’t work as required.

Mini-split line sets operate much like human arteries that connect major organs in the human body to regulate blood pressure. However, instead of oxygen and nutrients, they carry refrigerant.

Want to know how far can you run mini split lines? Then read on!

How Far Should Mini Split AC Lines Be Run?

So, how far mini-split refrigerant line be run, or how far can a mini-split be from the condenser? Well, 25 feet is the standard mini-split line length. This is how far an external condenser and indoor air handler should be placed.

Let’s delve into knowing mini-split line set length in different areas:

How Far Should Mini Split AC Lines Be Run

Length Of Mini Split Lines Up In Walls And Underground

Not everyone likes to have chunks of mini-split lines visible in the house. This is why many households run refrigerant lines on their walls.

It’s an increasingly common practice in the US to conceal mini-split refrigerant pipes in drywalls to improve the exterior and interior of a house.

Besides being hard to repair, hiding mini-split lines in house walls doesn’t impact your unit’s efficiency. Though it varies from house to house and manufacturer, the average line set size would be between 25 ft and 30 ft.

On the contrary, refrigerant pipes should never be buried underground unless they’re waterproof and insulated.

Due to this reason alone, underground pipes must reset within a watertight, thermally insulated, and sealed conduit. Ensure the line set doesn’t touch the soil, and the conduit won’t retain and collect water.

The length of mini-split lines underground is the same as up in walls, i.e., between 25 and 30 ft.

The Maximum Line Set Length Of A Mini Split AC And The Length Of Mini Split Lines In The Attic?

Many mini-split air conditioners have a maximum and minimum length requirement, and many outdoor devices come with refrigerant charges.

Refrigerant lines that are too long can compromise your unit’s performance and efficiency, while lines that are too short can also affect your system and may lead to early compressor failure.

As you know, 25 feet is the standard mini-split line set length. You can cut it to 10 feet minimum and ensure it’s re-flared. On the other hand, the maximum line set length of a mini-split AC can be 50 feet.

Make sure to avoid splicing refrigerant lines. In addition, if you make adjustments to the standard 25 feet line set, ensure to adjust its refrigerant charge.

Now that you know the maximum line set length, can you run mini split lines in the attic? Of course, you can!

You can use the standard 25 feet or lower line sets for the attic; however, make sure line sets are properly insulated to avoid hoarding frost and creating moisture problems.

Factors That Affect How Far A Mini Split Line Can Run

How far a mini-split line can run depends on several things such as size, distance, refrigerant, brand, etc. Nevertheless, here are the two key factors that affect how far a mini-split refrigerant line runs:

Factors That Affect Mini Split Line Length


Determining the maximum line length provided by your AC unit is vital when planning the placement and location of your outdoor and indoor units.

When measuring the distance, consider various features like corners and bends near the house, wall thickness, and vertical rise.


Distance also plays a critical role for refrigerant in mini-split line length. All mini-split air conditioners come with charged refrigerant.

Although it’s adequate for most installations, if you use extended mini-split line sets, you’ll need to include extra refrigerant to ensure your air conditioner operates appropriately.

People Also Ask (FAQ)

Here are frequently asked mini split line questions asked the most.

How far from the wall does a mini split need to be?

To place a mini-split outdoor system, you’ve to consider two major things: good airflow and room for service access.

Since all mini-splits have different space requirements, it’s crucial to check installation manuals. Nevertheless, the outdoor device can be placed anywhere, 20 to 28-inches away from the wall to ensure the air efficiently flows through the coil.

What size are the copper lines on a mini split?

Copper lines or tubes utilized in AC system applications are available in various sizes. Besides size ranges, the lines are also available in two types: soft tubing and hard tubing.

Nonetheless, copper lines on mini-split air conditioners range from 1/8-inches to 1-3/8-inches in nominal size.

Where do mini split lines usually run?

Most mini-split air conditioning systems have refrigerant lines, wires, and drain lines installed above ceilings.

However, if you’ve got a wall-mounted mini-split indoor unit, the lines can be seen under the roof unless you hide them in a wall.

Does line set size matter?

When placing refrigerant lines, ensure that you’ve got a proper line set size based on a total run length.

For instance, a 3-ton air conditioner requires a ¾-inch suction when there’s a 25 ft. or less distance; however, you’ll need anywhere from 7/8-inch to 1 1/8-inch suction for more than 25 ft. for full capacity and efficiency.

How do you extend a mini split line?

You can easily extend a mini-split line just by joining the male-to-male flare. In addition to that, you can purchase an extended mini-split line for your needs.

Make sure to check your AC unit’s manufacturer’s specifications on the maximum length of the line set.


Mini-split line sets are vital as they bring the heat in/out of the house, making sure you’ve got a cool ambiance and environment. Typically, 25 feet is the standard line set required to perform the effective installation.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.