Line set size by brand

Pick your mini-split's brand and capacity to get the right line set size — then shop it. Prefer to go by run length too? Use the size calculator.

How brands size line sets

Here's the part most people get wrong: line set diameter is set by your system's capacity, not the brand. A 12,000 BTU head needs the same line sizes whether it's a Pioneer, a Senville, or a Daikin — the manufacturer engineers every unit of that capacity for the same refrigerant flow.

What actually changes between brands is the connection:

Quick-connect / pre-charged (e.g. MrCool DIY) — proprietary line sets with sealed couplings that twist together. No vacuum, no flaring. Buy the matching brand line set in the right length.
Field-flared (Pioneer, Senville, Daikin, Mitsubishi and most others) — standard copper line sets you flare and torque on site, or buy pre-flared.

Line set size by capacity

System size	Typical line set (liquid × suction)
9,000 BTU	1/4" × 3/8"
12,000 BTU	1/4" × 1/2"
18,000 BTU	1/4" × 1/2"
24,000 BTU	3/8" × 5/8"
36,000 BTU	3/8" × 5/8"
48,000 BTU	3/8" × 5/8" (some 3/8" × 3/4")

These are the most common pairings. Exact diameters and the maximum line length are printed in your unit's installation manual — treat it as the final word.

Brand sizing guides

In-depth line set size guides for specific mini-split brands. Tap any brand for its full sizing chart:

MRCOOL line set sizes →DIY 9k–36k, Quick Connect lengths, and the 4th vs 5th Gen refrigerant difference. Pioneer line set sizes →By capacity and series, field-flared, R-410A and R-454B. Daikin line set sizes →Single-zone and multi-zone, field-flared, by capacity and series. Mitsubishi line set sizes →M-Series and P-Series, field-flared, by indoor and outdoor unit. Fujitsu line set sizes →Halcyon and AIRSTAGE, field-flared, sizes vary by series. Senville line set sizes →LETO and AURA, DIY-popular but flared, R-410A and R-454B. Della line set sizes →Vario, Optima, and Optima Pro — 1/4″ liquid line even at 36k, R-454B. Samsung line set sizes →WindFree and Max Heat by generation — line set not included in the box. R-410A and R-32. TOSOT line set sizes →Gree-built Cosmo, Aoraki, and Muse — sizes shift by series at 12k and 24k. R-32. Goodman line set sizes →Daikin-built E-Series ductless, plus how central Goodman systems differ. Panasonic line set sizes →ClimaPure and Exterios by generation — the 12k suction line moved with the R-32 switch. Cooper & Hunter line set sizes →Pre-flared DIY kits in standard sizes, R-410A and R-454B. LG line set sizes →Art Cool and standard wall-mounts, field-flared, now R-32. Carrier line set sizes →Performance and Infinity, field-flared, R-410A and R-454B Puron Advance. Gree line set sizes →Sapphire, Livo+, Vireo and Terra, field-flared, sizes vary by series. Bosch line set sizes →Climate 5000, field-flared, R-410A and R-454B on Gen 4. Midea line set sizes →DLCSRA consumer and EVOX professional lines, field-flared. Blueridge line set sizes →BMKH single-zone via Alpine Home Air, field-flared, R-410A.

Guide: how to verify a DIY mini-split in the AHRI Directory before you buy →

Guide: mini-split line set length limits by brand →

Common questions

What size line set does a MrCool DIY use?

MrCool DIY systems use proprietary pre-charged, pre-flared line sets. A 12,000–18,000 BTU DIY typically uses 1/4" × 1/2" and a 24,000–36,000 BTU DIY uses 3/8" × 5/8", in fixed lengths of 16, 25, 35, or 50 ft. Replace like-for-like with a MrCool DIY line set, and confirm against your unit's manual.

Does line set size depend on the brand?

The diameter is set by the system's capacity, not the brand — a 12,000 BTU unit uses the same line size across most brands. What varies is the connection type (quick-connect vs field-flared) and whether the line set is proprietary and pre-charged.

Can I reuse my existing line set?

Often yes, if the diameters match your new system, the run length works, and the lines are clean and leak-free. Existing R-410A line sets can frequently be reused. Always pressure-test and verify against the new unit's installation manual.

This tool provides general guidance based on common mini-split line set sizing by capacity. Exact line diameters, connection types, and maximum line lengths vary by model — always verify against the manufacturer's installation manual before purchasing or installing.