The outdoor unit can be fixed on:

• A concrete pad cast in place or a single piece pre-cast concrete or composite slab.
• A concrete patio or balcony.
• A timber slatted deck with anti-vibration mounts.
• Brackets fixed to a foundation or wall; note that anti-vibration isolators are required in these situations.
• A roof where the installation has been specifically designed (engineered) to accommodate live loads and wind forces acting on the roof, and it incorporates anti-vibration mounts.
• A specified base in accordance with manufacturer's instructions.

Installation of outdoor units must ensure the following:

• Units sit level, both side-to-side and front-to-back and cannot fall over
• Their weight is fully supported to prevent sagging
• Units have an unobstructed gap under them
• Units create no vibration; in cases where vibration is unavoidable, anti-vibration mounts should be used
• There is a suitable clearance underneath to allow for hosing, clearing of leaves and dirt, and clearance for snow
• Components used for fixing are corrosion-resistant (i.e. typically requires stainless steel)
• Any ground mounted units are placed on a pad on soil that is well drained and will not heave with frost
• Use wall brackets designed for attachment to foundation wall, where ground clearance allows
• Use anti-vibration isolators when mounting the outdoor unit to any component in direct contact with the structure (wall brackets, decks, etc.)
• Install surge suppressors at service disconnect to protect sensitive electronics. Alternatively, suppressors may be installed at circuit breaker boxes if devices are approved for such application. Follow device manufacturer's instructions and all applicable codes and standards.

Avoid:

• Avoid proximity to walkways or other areas where re-freezing defrost meltwater might cause a slip-and-fall hazard and/or damage the surface due to freeze/thaw cycles.
• Installing outdoor unit(s) directly under any drip line from the roof or other overhang that would subject them to falling snowmelt, ice, or concentrated rain runoff. When this is unavoidable, and a functioning gutter is not present, outdoor units shall be installed with drip caps or shields approved by the manufacturer.
• Drain pan heaters if drip cap and ground clearance are provided, except in extreme (e.g. marine) environments.

Do Not:

• Fix the unit onto a waterproof deck or a membrane roofing system, as the fixings will penetrate and compromise the waterproofing.
• Mount units on concrete or clay tile roofs (i.e. tiles are not strong enough to allow mounting and the weight of the installers working on the roof).
• Mount directly onto metal roofing, as roofing can act as a sound amplifier and direct fixing may cause corrosion of the roofing.
• Place multiple units above each other, or with outdoor fan outlet flow pointing directly at another unit, except when explicitly recommended by manufacturer.