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.
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.
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.
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.
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.
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.
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 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 recourses? Check out our multi-zone mini split buying guide.