It condenses refrigerant rather than cooling a fluid.

A dry cooler circulates water or glycol.

They look nearly identical on a roof.

Pipework, charge and failure modes all differ.

This is the commonest ordering error here.

Confirm which system it is serving.

The pipework is part of the refrigeration circuit.

Manufacturers limit length and vertical separation.

Charge is calculated for the installed run.

Oil return depends on line sizing and traps.

A bad run starves the compressor of oil.

That is a failure, not an inefficiency.

Keeping the system working in cold weather.

A cold condenser drops head pressure too far.

The expansion device then cannot function.

Fan speed control holds pressure up.

Flooding arrangements do the same differently.

Specify it for year-round cold climates.

More than it used to.

Regulation is moving in most markets.

Availability and price change over equipment life.

Service positions change with them.

Check the outlook, not just today's cost.

Ask what the supplier's transition plan is.

Pipe run limits, airflow and sound.

Distance to the indoor unit is a hard constraint.

Discharge air must not recirculate to the inlet.

Boundary sound limits often drive fan selection.

Service access is needed all round.

Settle these before the roof layout is fixed.

Coil cleanliness and fan condition, mostly.

Fouled fins raise condensing temperature.

That costs compressor energy continuously.

Leak checking is a regulatory duty in many markets.

Records are usually required with it.

Clean coils are the cheapest efficiency available.

Usually by pairing indoor and outdoor units.

Each circuit is independent of the others.

Loss of one condenser costs one circuit.

Shared pipework would defeat that.

Confirm circuits are genuinely separate.

Match the count to the availability target.