Mini Split Installation Tips: How & Where to Install Your Outdoor Unit

Installing a mini split system can be a daunting task, especially for someone who has never done it before. In order to successfully install your new unit, there are a few key details to keep in mind to make the installation process a bit easier. By taking these factors into consideration, you’ll ensure that your mini split installation is as smooth and successful as possible.

Mini Split Weight

To begin, it’s important to choose a location that can support the weight of your mini split unit. Condenser units can weigh anywhere from 80 to 250 pounds, and soft ground may cause the unit to shift, resulting in issues with the connections.

For the most secure placement possible, pour a concrete pad on the ground and mount the unit with anchor bolts. If you do not have the ability to mount the unit to concrete, a great alternative is to use a pre-engineered condenser pad. These pads are designed to support the weight of a unit when placed on solid ground. Always make sure to level your pad prior to securing the unit to it.

Anchor BoltsMini Split Mount Points

 

Airflow

Airflow is the key to your mini split’s performance. When looking for a place to install your mini split, you should choose an area that offers optimum inlet and outlet airflow and is easily accessible for inspection, maintenance, and service. Do not install your unit where it will be exposed to heat or steam from sources like boiler stacks, chimneys, steam relief ports, other air conditioning units, kitchen vents, plumbing vents, etc. Such extreme temperatures may degrade performance or cause damage to the unit. When using multiple outdoor units, avoid placing them where discharge of one outdoor unit will blow into the inlet side of an adjacent unit.

LG Outdoor Unit Clearance Guide

Appropriate airflow through the outdoor unit coil is critical for proper operation. Clearances ensure that heat radiation and discharge airflow aren’t restricted around the outdoor unit. The exact dimensions will depend on your specific unit, but in general it is best to keep any objects 28 inches from the front air outlet, 12 inches from the rear air inlet, 40 inches from the top, and 12 to 24 inches from either side. The diagram on the right shows the basic configuration.

*Pro Tip: If only the minimum amount of clearance is used, the unit performance can decrease by up to 15%. Never use less than the minimum clearance. Excess heat buildup or poor airflow can cause the unit to fail.

Wind

Windy conditions can interfere with your unit in several ways. From knocking the unit over to disrupting the condenser fan, you want to make sure that wind gusts do not have a negative impact on your mini split.

Wall and rooftop installations are most susceptible to wind issues; therefore, any unit installed on a wall or roof must be secured using the unit’s mounting points.

Ground installations are not without risk of wind issues, either. If you live in a high wind area like a coastal location, a wind barrier may be necessary in order to achieve the best performance.

Diagram of a windbreaker/barrier and mini split unit Mini Split Installation in Coastal Area

The wind barrier needs to be constructed of a strong material like concrete in order to effectively obstruct the wind. The height and width of the barrier should be large enough to fully shield the unit. It should be at least 50% wider and taller than the dimensions of the outdoor unit. The unit must be placed at least 28 inches away from the wall to allow for proper air flow around it.

*Pro Tip: Anti-vibration dampers are critical in high wind areas. These are often included with wall brackets and stands, but they may be added if you’re ground mounting. Dampers will not only prevent the unit from audibly shaking but will also help to keep it secure and level.

LG Roof Mount Installation

Rain

Rain itself will not have a major impact on the performance of the unit. However, the unit should never be placed in an area where there is standing water. If your location is prone to flood, consider a mini split stand, wall mounting, or roof mounting. The outdoor unit is water resistant, not waterproof. If you are in an area with a lot of rainfall, it may be wise to install hoods over the unit’s air inlet and outlet. A roof or covering may also be used, but it must be at least 40 inches above the unit.

Snow

As heat pump performance has improved, so too has the usage of mini split units as primary heat sources. If you plan on using your heat pump as a primary heat source, you must make sure that your unit is clear of snow. Keep the following in mind if you’re concerned about snow’s effects on your mini split:

  • The unit should be mounted higher than the anticipated snowfall for that location.
  • The front fan and rear coil must be free of snow and ice. Ice buildup on the coils can cause the unit to shut down or unexpectedly malfunction.
  • The mounting platform should not have any additional flat surfaces for snow buildup.
  • If more than 4 inches of snow has accumulated on top of the unit, it must be removed prior to operation.

In very snowy areas, a hood or roof may be advisable. This surface must be at least 40 inches above the top of the unit, and it should be wide enough to fully protect your mini split. It is also important to install the outdoor unit air inlet and discharge areas away from prevailing winter winds. Always be sure to seal all piping and electrical access panels to prevent any moisture from getting inside.

Mini Split Insulation

All refrigerant piping — including connections, service valves, and elbows — should be completely and correctly insulated with closed cell pipe insulation.  To prevent heat loss or heat gain through the refrigerant piping, all refrigerant piping including liquid and vapor lines should be insulated separately.

Keep the following insulation tips in mind when installing your mini split system:

  • Insulation should be a minimum of half an inch thick.
  • Thickness may need to be increased based on ambient conditions and local codes.
  • All insulation joints should be glued tight with no air gaps.
  • The insulation material must fit snugly against the refrigeration pipes with no air space between it and the pipes.
  • It is best to purchase pre-insulated lines to ensure proper coverage.

*Pro Tip: All pipe insulation exposed to outdoor elements should be properly protected with PVC, aluminum vapor barrier, conduit or wide vinyl tape, or alternatively placed in a weather-resistant enclosure such as a pipe rack with a top cover. This will protect the insulation from drying out and cracking over time.

Mini Split Line Set Guide

Mini Split Installation Done Right

Making the right accommodations for your mini split outdoor unit is crucial to proper function and performance in the long run. Cooling and especially heating performance depend heavily on where and how you install your unit. Please refer to the specific manual for your model to verify clearances. And of course, always follow local codes when installing your mini split system. Looking for more resources? Check out our multi-zone mini split buying guide.

Mickey Luongo

Mickey is the resident heating and air conditioning expert.

27 Comments

Bryan Spanos

about 10 months ago

I live in Massachusetts and would prefer not to attach the unit directly to my house. How much vibration or noise is expected if I did? I will have a TV on the inside of the wall.

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Mickey Luongo

about 10 months ago

It depends on the bracket you use. We carry the Quick Sling QSWB2000 which includes rubber washers that help to prevent vibration.

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Bryan Spanos

about 10 months ago

Thanks! Would you recommend putting it on the ground or on the house? It will have a heat pump

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Mickey Luongo

about 10 months ago

Since you are in Massachusetts, you have to worry about snow. Putting it on the ground would eliminate any vibration issue, but you would need to make sure that it is 1-2 feet off the ground.

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Nick

about 7 months ago

I would like to mt the outside unit on my house foundation about 12" from the ground. How close can the back of the unit be to the fondation?

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Mickey Luongo

about 7 months ago

It should be at least 12 inches from the foundation.

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Vince

about 4 months ago

Hi - Is it possible to install one of the smaller Minisplit condensors in a PTAC space?

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Mickey Luongo

about 4 months ago

No, you can't really reuse the space that the PTAC was in. The mini split condenser must be fully outside. It can either be placed on the ground or mounted to an outside wall.

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Andrew

about 4 months ago

Is there a maximum distance that the compressor can be from the air handling unit? I would like to install my compressor unit on the ground, and my room being cooled is on the second floor. Can I simply pipe everything up and across the roof to the air handling unit? I am looking at a Gree Rio 18k btu unit. Trying to avoid noise/vibration caused by mounting the compressor on the roof as I the application is for a sound studio.

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Mickey Luongo

about 4 months ago

Every unit has a maximum distance that the line set can be run. There will also be a maximum height separation. Check the specs of the unit you are looking at to be sure that it will work for your application.

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Scott S

about 3 months ago

1. how long of a run can the piping be from the condenser to the head units? 2. does the length of run effect the efficiency of the head units? 3. where is the ideal location for the condenser ion regards to the sun , shade, north east or west side of house etc., also can it be installed under a porch ?

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Mickey Luongo

about 3 months ago

1. It depends on the specific unit you choose. Some are limited to 25 feet. Others can go over 100 feet. 2. No, length does not impact efficiency. 3. It can be installed under a porch as long as there is still enough air flow around the unit.

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Danny H

about 3 months ago

can the condenser unit be mounted higher then the wall units?

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Mickey Luongo

about 3 months ago

Yes, they can be, as long as the height difference does not exceed the maximum stated in the specifications.

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Jason

about 3 months ago

How do you handle going around gutters for a 2nd floor mini split? Not really finding any examples online.

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Mickey Luongo

about 2 months ago

Do you have a picture of the gutter you need to go over?

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Adam A

about 2 months ago

How far should the condenser be placed from a neighbor's window, or from an attached party wall? Is it better to attach the condenser to the foundation or on a stand on concrete floor in order to prevent any potential vibrations or noise issues with the neighbor? I was told the line set should be 18" away from the party wall separates the 2 houses.

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Mickey Luongo

about 2 months ago

Installing the unit on the ground or a stand would prevent the most vibrations.

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Eugene

about 2 months ago

Is it advantageous to install the air handler above a window within 7 feet of a ceiling fan to help circulate the air around a larger room?

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Mickey Luongo

about 2 months ago

Any additional air circulation will always help an air conditioner.

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Ted

about 2 months ago

I was wondering if I can mount the exterior unit higher off the ground, say 4 feet or so. It will be mounted with brackets to the wall. I'm nervous about having to cut down the included piping. Also, I've bought a 240 system. I can just wire that to a 220 exterior plug, right? I was using a 220 interior plug for a wall unit that I'm replacing with this. Thanks so much for replying to all of us!

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Mickey Luongo

about 2 months ago

You can mount the unit as high as you want using a bracket. In most cases, 240 volts is the same as 220 volts. It cannot be wired to an exterior plug that is already in use, it needs a dedicated line. Also, most mini splits are hard wired and require this use of a quick disconnect switch.

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Ted

about 2 months ago

Thank you!!!

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Ted

about 1 month ago

I am installing the outSide part of my ductless heat pump in a screenroom attached to the house . My installation Manuel say that 24" clearance is required above the outdoor unit . How important is this ? I would like install it with 18" clearance above because of limited space .

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Mickey Luongo

about 1 month ago

The clearance is very important. If you do not have enough clearance, it can cause the unit to overheat and could void your warranty.

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Ron

about 2 weeks ago

I bought a senville quad mini split. I'm having trouble on mounting the heads in the rooms. I bought 2 with 25' line sets the other 2 have 15’. Would it be ok to run the lines through the ceiling? I'm mount the outside unit on the gable an running the lines through the attic. So the lines would run up about 18" then 90 towards the outside unit. Then 90 in to the unit these are fixed lines I will have excess line any special way to leave the excess lines? The gable side I'm mounting does face the wind i wouldn't think it would be any different than mounting it on the roof.

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