Cooper & Hunter line set sizes
The right line set diameter for your Cooper & Hunter mini-split by capacity — plus what the brand's pre-flared kits do and don't do for a DIY install. Prefer to size by run length too? Use the size calculator.
Cooper & Hunter line set size by capacity
Line set diameter is set by your system's capacity. Cooper & Hunter follows the standard mini-split pairings, so match your unit's BTU rating to the liquid-and-gas pair below — these match the kit sizes Cooper & Hunter sells.
| Cooper & Hunter system size | Line set (liquid × gas) |
|---|---|
| 9,000 BTU | 1/4" × 3/8" |
| 12,000 BTU | 1/4" × 3/8" |
| 18,000 BTU | 1/4" × 1/2" |
| 24,000 BTU | 3/8" × 5/8" |
| 36,000 BTU | 3/8" × 5/8" |
Cooper & Hunter sells matching installation kits in all three sizes — 1/4" × 3/8", 1/4" × 1/2", and 3/8" × 5/8" — in 16, 25, and 50 ft lengths, with pre-flared, pre-insulated copper and the control wire. Buy the diameter that matches your unit, in a length sized to your run. Always confirm the sizes against your manual.
Pre-flared kits help — but it's still a vacuum install
Cooper & Hunter is a popular DIY-friendly brand, and its pre-flared, pre-insulated kits remove one of the trickier steps. But a C&H is still a standard field-flared system, not quick-connect: you connect the flares and pull a vacuum to remove air and moisture before opening the service valves. Plan on a vacuum pump and typically EPA 608 certification. For a true no-vacuum route, that's a pre-charged quick-connect brand such as MRCOOL DIY — see pre-charged line sets.
Lengths and refrigerant
Because Cooper & Hunter uses standard line sets, you size to your run — common stocked lengths are 16, 25, 35, and 50 ft. R-454B systems ship pre-charged for up to about 25 ft; longer runs need a calculated top-up. Watch your unit's maximum line length and vertical lift, both listed in the manual.
Match the refrigerant. Cooper & Hunter sells both R-410A and newer R-454B systems as the industry replaces R-410A after January 1, 2026. The copper line set is the same either way, but your tools, gauges, and any added charge must match your system's refrigerant — check the data plate before you buy.
How to find your Cooper & Hunter model's line set size
- Identify the series and capacity. Note the model number and BTU — Cooper & Hunter sizing follows the capacity, but always verify the exact figures and the included kit size.
- Check the installation manual. It lists the exact liquid and gas diameters, the maximum line length, and the refrigerant for your model — the final word.
Common questions
What size line set does a Cooper & Hunter 12,000 BTU use?
A Cooper & Hunter 12,000 BTU mini-split uses a 1/4" liquid line with a 3/8" gas line, the same pair as the 9,000 BTU models. Cooper & Hunter sells matching pre-flared kits in this size. Confirm against your model's installation manual.
Do Cooper & Hunter mini-splits use flared or quick-connect line sets?
Cooper & Hunter uses standard field-flared line sets, not pre-charged quick-connect. They sell pre-flared, pre-insulated kits to make it easier, but you still pull a vacuum before opening the service valves, so the install needs a vacuum pump and typically EPA 608 certification.
What size line set does a Cooper & Hunter 24,000 BTU use?
A Cooper & Hunter 24,000 BTU mini-split uses a 3/8" liquid line with a 5/8" gas line, and 36,000 BTU units use the same 3/8" × 5/8" pair. The 18,000 BTU steps down to 1/4" × 1/2". Verify against your unit's manual.
What refrigerant do Cooper & Hunter mini-splits use?
Cooper & Hunter sells both R-410A and newer R-454B systems, with R-454B units pre-charged for up to about 25 ft of line set as the industry phases out R-410A. Match your line set, tools, and any added charge to your unit's refrigerant.
This page provides general guidance on Cooper & Hunter mini-split line set sizing based on published Cooper & Hunter specifications. Exact line diameters, included kit size, maximum line length, and refrigerant (R-410A or R-454B) vary by model — always verify against your unit's official installation manual before purchasing or installing.