TL;DR
A line set is the pair of copper refrigerant pipes — a small liquid line and a larger insulated suction line — that connects an air conditioner or heat pump's outdoor unit to the indoor coil. Common residential sizes pair 3/8-inch liquid with 3/4- or 7/8-inch suction tubing, and length and elevation limits come from the equipment manufacturer.
What it means
A line set is the pair of copper refrigerant pipes — a small liquid line and a larger insulated suction line — that connects an air conditioner or heat pump's outdoor unit to the indoor coil. Common residential sizes pair 3/8-inch liquid with 3/4- or 7/8-inch suction tubing, and length and elevation limits come from the equipment manufacturer. Replacement quotes should say whether the existing run will be reused, flushed, or replaced, since old oil and acid can shorten a new compressor's life.
Where it sits in the glossary
Line set is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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