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Mechanical / HVACaka: split ACaka: central split systemaka: conventional split system

Split System

In Plain English

An HVAC system with separate indoor and outdoor components connected by refrigerant lines.

Definition

An HVAC system in which the refrigeration components are split between an indoor unit (air handler or evaporator coil) and an outdoor unit (condensing unit), connected by refrigerant piping. Split systems are the most common residential and light commercial HVAC configuration. They offer quieter indoor operation than packaged units because the noisy compressor and condenser fan are located outside.

Why It Matters in Bidding

Split systems are the default HVAC approach on most residential and light-commercial bids, so estimators must scope both the indoor and outdoor units plus the refrigerant line set, electrical, and condensate piping that connect them. Misreading tonnage, efficiency rating, or line-set runs can leave the mechanical bid short, and long refrigerant runs or roof-mounted condensers add labor and material the drawings may not make obvious.

Example

Pricing a tenant build-out, the HVAC estimator counts four split systems on the plans and adds line-set lengths, condenser pads, and a crane pick for the rooftop condensers that the floor plan alone did not capture.

Related Terms

Condensing UnitAir HandlerMini-SplitHeat Pump

Frequently Asked Questions

Beyond the indoor and outdoor units, estimators frequently overlook the refrigerant line set length, condensate drains, condenser pads or roof curbs, disconnects and whips, low-voltage thermostat wiring, and startup or commissioning. On rooftop installs, rigging or crane time can be a major line item the plan view does not reveal.
Higher minimum efficiency ratings required by code or specs raise equipment cost and can change unit sizing and electrical loads. Estimators should price the exact efficiency tier the specs call out rather than a baseline unit, because substituting a lower-rated condenser to win the bid creates a compliance and warranty exposure after award.
Packaged units combine all components in one cabinet and can cut installation labor, but split systems often cost less in equipment and suit spaces lacking roof access. The right choice is usually dictated by the specs and building layout, so estimators price what is specified rather than swapping configurations to chase a lower number.

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