TryBuildCalcRefrigerant Line Set Length, Capacity & Charge Calculator (Equivalent Length, Capacity Impact & Refrigerant Charge)
Calculate your refrigerant line set's length, capacity impact, and charge.
🕒 Last updated: September 15, 2026
Inputs
ℹ️The AC/heat pump/mini-split system's rated capacity — drives both the capacity-derating and refrigerant-charge calculations.
ℹ️Air conditioner or heat pump — changes the elevation limit above the indoor unit and whether a liquid line solenoid or accumulator applies.
ℹ️Check your outdoor unit's nameplate. Sets the max line length Goodman/Amana supports — single-stage scroll/reciprocating allows the longest runs.
ℹ️The line set's larger (vapor/suction) line — must match your equipment's actual spec, not a free choice. Options shown are limited to what's sourced for the selected capacity.
ℹ️The actual physical distance the line set runs, not accounting for elbows — used directly for the refrigerant charge calculation.
ℹ️Number of 90-degree (long-radius) bends in the line set — each adds equivalent length beyond the straight distance.
ℹ️Number of 45-degree bends in the line set — adds less equivalent length per bend than a 90-degree elbow.
ℹ️Height difference between the outdoor and indoor units — affects whether an oil trap is required or a manufacturer elevation limit is exceeded.
ℹ️"Same Level" applies only up to 10 ft of separation. Elevation limits are asymmetric by direction and equipment type — see the flags below the results.
Total Equivalent Length
53 ft
50 ft straight + 2 × 90° and 0 × 45° elbows
System
Type: Air Conditioner
Compressor: Single-Stage — Scroll or Reciprocating Compressor
Capacity: 3 Ton (36,000 BTU/hr)
Suction line: 3/4 in
Liquid line: 3/8 in
Line Set Routing
Straight length: 50 ft (max 200 ft)
90° elbows: 2
45° elbows: 0
Equivalent length: 53 ft (max 250 ft)
Capacity Impact
Capacity multiplier: 0.999
Rated capacity: 36,000 BTU/hr
Derated capacity: 35,964 BTU/hr
~36 BTU/hr lost to line-length pressure drop.
Refrigerant Charge
Additional charge needed: 23.5 oz
Beyond the 15 ft factory-charge baseline, R-410A only.
Elevation & Installation
Outdoor unit position: Same level
Elevation difference: 0 ft
Within Goodman/Amana limits: Yes
Assumptions Used
Every figure here traces to Goodman/Amana's own published TP-107 "Long Line Set Application, R-410A" guideline — this is that manufacturer's specific published guidance, not a universal industry constant, since other manufacturers publish meaningfully different thresholds for their own equipment (see Limitations). Total Equivalent Length is the straight (linear) length plus a per-elbow equivalent-length addition for long-radius 90° and 45° elbows only (short-radius elbows add slightly more per elbow than this calculator models). Maximum Equivalent/Linear Length depends on your selected compressor type — 250/200 ft for single-stage scroll or reciprocating compressors, 150/150 ft for single-stage rotary or two-stage. For two-stage HEAT PUMPS specifically, Table 5-3's own footnotes additionally prohibit 7/8in suction at 24,000 BTU entirely, 7/8in suction beyond 80 ft equivalent length at 36,000 BTU, and 1-1/8in suction beyond 80 ft equivalent length at 48,000/60,000 BTU — flagged separately above when applicable. Capacity Multiplier is looked up from a table of capacity x suction diameter x equivalent length, linearly interpolated between the nearest documented length columns (25-250 ft) and clamped at the table's own boundaries rather than extrapolated beyond them. Two cells in that table (30,000 BTU/3-4in/175ft and 60,000 BTU/7-8in/200ft) printed values that broke the otherwise-smooth pattern of their row; this calculator adjusts them to match the surrounding values as an INFERRED correction, not an official manufacturer erratum — if your exact scenario lands at one of those two cells, cross-check directly against the published PDF. Additional Refrigerant Charge uses the ACTUAL straight length (not equivalent length) beyond the 15 ft factory-charge baseline, at a rate specific to the 3/8in liquid line paired with your selected suction diameter — this figure is R-410A only; R-32 and R-454B systems use different refrigerant densities and are not modeled, since no consistent charge-rate figure was found for them. No published rate exists for 1/2in suction at all — that combination falls back to a liquid-line-only rate that likely understates the true charge (see the Refrigerant Charge card above when this applies). "Same Level" only applies up to 10 ft of separation between the units — beyond that, TP-107 says to categorize the installation as Above or Below instead. The elevation rules are genuinely asymmetric by direction and equipment type: an outdoor unit installed BELOW the indoor unit has a hard maximum of 80 ft (any equipment type) plus an always-required inverted suction trap, a required liquid line solenoid (any equipment type, unless a non-bleed TXV is used), and, for air conditioners over 79ft, an accumulator; an outdoor unit ABOVE the indoor unit has no stated hard maximum for a single-stage air conditioner, an 80 ft hard maximum for a single-stage heat pump, and a 25 ft hard maximum for two-stage equipment of either type — separately, an oil trap is required above 80 ft regardless of equipment type, and heat pumps (any position) require the same liquid line solenoid. This is a planning estimate — always verify against your specific installed or selected unit's own installation manual before purchasing materials or beginning installation.
What Is a Refrigerant Line Set Calculator?
This calculator estimates three real consequences of a refrigerant line set's length and routing for an R-410A split-system AC, heat pump, or mini-split: total equivalent length (straight length plus elbow losses), how much rated capacity a long run costs you, and how much extra refrigerant charge the installation needs beyond the factory baseline.
Every figure traces directly to Goodman/Amana's own published TP-107 "Long Line Set Application, R-410A" installation guideline — real manufacturer tables, not an invented formula. This calculator does NOT tell you which line diameter to buy: that's genuinely specific to your selected equipment's own spec sheet, and varies meaningfully between manufacturers. Enter the diameter your equipment actually calls for, and this calculator reports the real, sourced consequences of your specific length and routing.
Why this needs its own calculator, not just a rule of thumb:
- Capacity loss from a long line set is a real, measurable effect (up to roughly 10% at the longest documented lengths) — not something a flat length limit alone tells you
- Refrigerant charge addition depends on actual line length AND the specific suction diameter, not a single flat oz/ft rate
- Elevation rules are genuinely asymmetric by direction and equipment type — an outdoor unit below the indoor unit always has an 80 ft hard maximum, while above depends on your specific equipment: a single-stage air conditioner has no stated hard maximum (only an oil-trap accessory beyond 80 ft), but a single-stage heat pump (80 ft) or two-stage system (25 ft) has its own hard maximum too, a distinction easy to miss
- Elbow count and type meaningfully change total equivalent length, which drives the capacity-loss lookup — a rough actual-length-only estimate can meaningfully understate the real derating
Refrigerant Line Set Formula: How Is It Determined?
Total equivalent length comes from straight length plus elbow losses. Capacity impact and refrigerant charge are both looked up/computed from that length and your selected system capacity and suction diameter. See Limitations for what this doesn't model.
Total Equivalent Length
Equivalent Length (ft) = ceil(Straight Length + 90° Elbows x Loss(90°) + 45° Elbows x Loss(45°))
Per-elbow equivalent-length values (Goodman TP-107 Table 5-1) are specific to LONG-RADIUS fittings and vary by suction line diameter — e.g. a 90° long-radius elbow adds 1.5 ft at 3/4in, 1.7 ft at 7/8in. A required minimum, rounded UP. Short-radius elbows (not modeled separately) add somewhat more per elbow than long-radius — see Limitations.
Capacity Impact
Capacity Multiplier = lookup(System Capacity, Suction Diameter, Equivalent Length)
Derated Capacity (BTU/hr) = System Capacity x Capacity Multiplier
The capacity multiplier is looked up directly from Goodman TP-107's own published table (capacity x suction diameter x equivalent length, 25-250 ft in 25 ft steps), linearly interpolated between the two nearest documented length columns and clamped at the table's own boundaries. A longer equivalent length or a smaller suction diameter both increase pressure drop, which is what actually costs the system rated capacity.
Additional Refrigerant Charge
Additional Refrigerant (oz) = max(0, Straight Length − 15 ft) x Rate(Suction Diameter)
Uses ACTUAL straight length, not equivalent length — refrigerant volume depends on the real physical tubing installed, not the pressure-drop-equivalent figure used for capacity derating. R-410A residential outdoor units are factory-charged for the first 15 ft of line set (Goodman TP-107); the per-foot rate beyond that baseline is specific to the 3/8in liquid line paired with your selected suction diameter (Table 5-5), ranging 0.60-0.78 oz/ft.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value |
|---|---|
| System capacity | 3 Ton (36,000 BTU/hr) |
| Suction line diameter | 3/4 in |
| Straight length / elbows | 50 ft / 2× 90°, 0× 45° |
| Elevation / outdoor position | 0 ft / Same level |
Step 1 — Total Equivalent Length
| Calculation | Result |
|---|---|
| Elbow loss at 3/4 in (Table 5-1, long-radius) | 1.5 ft per 90°, 0.7 ft per 45° |
| Equivalent length = ceil(50 + 2 × 1.5 + 0 × 0.7) | 53 ft |
Step 2 — Capacity Multiplier (Goodman TP-107 Table 5-3)
| Calculation | Result |
|---|---|
| 53 ft falls between the documented 50 ft (1.00) and 75 ft (0.99) columns for 3 Ton/3/4 in — linearly interpolated | 0.999 |
| Capacity multiplier | 0.999 |
Step 3 — Derated Capacity
| Calculation | Result |
|---|---|
| Derated capacity = 36,000 × 0.999 | 35,964 BTU/hr |
| Capacity lost to line length | 36 BTU/hr |
Step 4 — Additional Refrigerant Charge
| Calculation | Result |
|---|---|
| Billable length = max(0, 50 − 15 ft factory baseline) | 35 ft |
| Additional refrigerant = 35 ft × 0.67 oz/ft (3/4 in rate, Table 5-5) | 23.5 oz |
Step 5 — Length & Elevation Checks
| Check | Result |
|---|---|
| 53 ft equivalent vs 250 ft max, 50 ft linear vs 200 ft max (Single-Stage — Scroll or Reciprocating Compressor) | Within limits |
| 0 ft vs 10 ft Same Level max | Within limits |
Therefore, this installation has a 53 ft total equivalent length, a derated capacity of 35,964 BTU/hr (down from 36,000 BTU/hr rated), and needs 23.5 oz of additional R-410A refrigerant beyond the factory charge. This configuration is within Goodman/Amana's published limits.
Essential Checklist+−
Complete these critical checks before approving the work or proceeding to the next construction stage.
✓Inputs & Sizing Method+-
- System Capacity matches the actual equipment's rated capacity, not a guessed or rounded figure
- System Type and Compressor Type match the actual outdoor unit's nameplate/spec sheet, not a default guess
- Suction Line Diameter matches the actual equipment's spec sheet or installation manual, not a free choice
- Straight (Linear) Line Length measured or accurately estimated from the actual routing plan, not guessed
- Total Equivalent Length and Straight Length both confirmed within the published maximum for the selected compressor type
- If this is a two-stage heat pump: Suction Line Diameter confirmed against Table 5-3's own diameter restrictions, not just the general capacity/diameter list
- Outdoor Unit Position (same level / above / below) matches the actual site layout, not assumed — including confirming "Same Level" genuinely applies (10 ft or less separation)
✓Capacity & Refrigerant Charge Verification+-
- Additional Refrigerant Charge added to the factory charge BEFORE final commissioning, using the correct sign (adding, not replacing)
- System confirmed to use R-410A refrigerant — this calculator's charge-rate figures do not apply to R-32, R-454B, or other refrigerants
- Final subcooling/superheat verification planned as a required step after adding the calculated refrigerant charge, not skipped
✓Elevation & Installation Requirements+-
- Vertical Elevation Difference measured or accurately estimated, not guessed
- If flagged: an inverted oil trap installed at the indoor unit's suction connection before commissioning
- If outdoor unit is below indoor: an inverted suction trap installed (always required), plus an accumulator if this is an air conditioner over 79 ft of actual line length
- If this is a heat pump (any position), OR an air conditioner below the indoor unit: liquid line solenoid installed at the outdoor unit, unless a non-bleed TXV is used
- If flagged as exceeding any published hard maximum (length OR elevation): an alternative equipment selection, routing, or manufacturer-specific accessory solution identified before proceeding
- Actual installed or selected equipment's own manufacturer installation manual cross-checked against this calculator's Goodman/Amana-sourced figures
✓Commissioning & Final Checks+-
- Line set pressure-tested and confirmed leak-free before evacuation and final charging
- System evacuated to the equipment manufacturer's specified vacuum level before charging, not skipped or rushed
- Licensed HVAC/refrigeration technician sign-off obtained before relying on this as a final design
Full QC Checklist+−
Verification checklist for a refrigerant line set sizing estimate — covering inputs/sizing method, capacity and refrigerant charge verification, elevation and installation requirements, and commissioning/final checks. Use the Essential Checklist for critical checks before finalizing, expand to Full QC Checklist for complete verification.
✓Inputs & Sizing Method+-
- System Capacity matches the actual equipment's rated capacity, not a guessed or rounded figure
- System Type and Compressor Type match the actual outdoor unit's nameplate/spec sheet, not a default guess
- Suction Line Diameter matches the actual equipment's spec sheet or installation manual, not a free choice
- Straight (Linear) Line Length measured or accurately estimated from the actual routing plan, not guessed
- Elbow counts (90° and 45°) reflect the actual planned routing, not a rough guess
- Total Equivalent Length and Straight Length both confirmed within the published maximum for the selected compressor type
- If this is a two-stage heat pump: Suction Line Diameter confirmed against Table 5-3's own diameter restrictions, not just the general capacity/diameter list
- Outdoor Unit Position (same level / above / below) matches the actual site layout, not assumed — including confirming "Same Level" genuinely applies (10 ft or less separation)
✓Capacity & Refrigerant Charge Verification+-
- Capacity Multiplier and Derated Capacity reviewed and understood as a real, sourced consequence of line length — not treated as an error to dismiss
- Additional Refrigerant Charge added to the factory charge BEFORE final commissioning, using the correct sign (adding, not replacing)
- System confirmed to use R-410A refrigerant — this calculator's charge-rate figures do not apply to R-32, R-454B, or other refrigerants
- If using 1/2in suction: Additional Refrigerant Charge treated as an approximate floor, not a validated figure
- Final subcooling/superheat verification planned as a required step after adding the calculated refrigerant charge, not skipped
- Equivalent Length (used for capacity derating) and Straight Length (used for refrigerant charge) not confused with each other
✓Elevation & Installation Requirements+-
- Vertical Elevation Difference measured or accurately estimated, not guessed
- If flagged: an inverted oil trap installed at the indoor unit's suction connection before commissioning
- If outdoor unit is below indoor: an inverted suction trap installed (always required), plus an accumulator if this is an air conditioner over 79 ft of actual line length
- If this is a heat pump (any position), OR an air conditioner below the indoor unit: liquid line solenoid installed at the outdoor unit, unless a non-bleed TXV is used
- If flagged as exceeding any published hard maximum (length OR elevation): an alternative equipment selection, routing, or manufacturer-specific accessory solution identified before proceeding
- Actual installed or selected equipment's own manufacturer installation manual cross-checked against this calculator's Goodman/Amana-sourced figures
- Long-radius elbow fittings used in the actual installation, matching this calculator's modeled elbow-loss assumption
✓Commissioning & Final Checks+-
- Line set pressure-tested and confirmed leak-free before evacuation and final charging
- System evacuated to the equipment manufacturer's specified vacuum level before charging, not skipped or rushed
- Suction line insulated to at least the current locally-adopted code minimum (R-3 per the 2024 IRC; some jurisdictions may still enforce the R-4 minimum from the 2015/2018 IRC)
- Line set properly supported/strapped and not in direct contact with building structure along its full run
- Licensed HVAC/refrigeration technician sign-off obtained before relying on this as a final design
Refrigerant Line Set Reference Tables
Elbow equivalent-length losses, refrigerant charge rates, and typical diameter tiers, per Goodman/Amana TP-107 and cross-sourced secondary references.
| Suction Diameter | 90° Long Radius | 45° Long Radius |
|---|---|---|
| 3/4 in | 1.5 ft | 0.7 ft |
| 7/8 in | 1.7 ft | 0.8 ft |
| 1-1/8 in | 1.6 ft | 1.0 ft |
Additional Refrigerant Rate (3/8in liquid line)
| Suction Diameter | Rate (oz per foot beyond 15 ft baseline) |
|---|---|
| 5/8 in | 0.63 oz/ft |
| 3/4 in | 0.67 oz/ft |
| 7/8 in | 0.74 oz/ft |
| 1-1/8 in | 0.78 oz/ft |
Typical Diameter by System Size (cross-sourced starting point, not this calculator's primary output)
| System Size | Typical Liquid / Suction |
|---|---|
| 1.5-3 ton | 3/8 in / 3/4 in |
| 3.5-5 ton | 3/8 in / 7/8-1 in |
Maximum Length by Compressor Type
| Compressor Type | Max Equivalent Length | Max Linear Length |
|---|---|---|
| Single-Stage (Scroll/Reciprocating) | 250 ft | 200 ft |
| Single-Stage (Rotary) | 150 ft | 150 ft |
| Two-Stage | 150 ft | 150 ft |
Elevation Maximum by Position
| Position | System Type / Staging | Elevation Maximum |
|---|---|---|
| Same Level as Indoor Unit | Any | 10 ft (beyond this, categorize as Above or Below instead) |
| Above Indoor Unit | Single-stage air conditioner | No stated hard maximum (subject to max equivalent length) |
| Above Indoor Unit | Single-stage heat pump | 80 ft (some specific models rated to 200 ft — check your unit's own manual) |
| Above Indoor Unit | Two-stage (AC or heat pump) | 25 ft |
| Below Indoor Unit | Any | 80 ft |
Two-Stage Heat Pump Suction Diameter Restrictions
Table 5-3's own footnotes additionally prohibit specific suction diameters for two-stage heat pumps at certain capacities, independent of the length limits above.
| System Capacity | Restricted Diameter | Restriction |
|---|---|---|
| 24,000 BTU/hr (2 ton) | 7/8 in | Not approved at any length |
| 36,000 BTU/hr (3 ton) | 7/8 in | Not approved beyond 80 ft equivalent length |
| 48,000 / 60,000 BTU/hr (4-5 ton) | 1-1/8 in | Not approved beyond 80 ft equivalent length |
When should you use this calculator?
- Planning a split-system AC, heat pump, or mini-split installation with a line set longer than a short, standard run.
- Checking how much rated capacity a specific length and elbow count will actually cost you before committing to a routing plan.
- Calculating how much additional R-410A refrigerant to have on hand for a long-line installation.
- Confirming whether an elevation difference needs an oil trap or exceeds a documented manufacturer maximum.
- Checking whether your planned length exceeds Goodman/Amana's maximum for your specific compressor type before committing to a routing plan.
- Confirming whether an inverted suction trap, accumulator, or liquid line solenoid applies to your specific configuration.
- Comparing how suction diameter or routing changes affect capacity and charge (via Compare mode).
Quick Sizing Tips
- Always use the suction diameter your actual equipment's spec sheet or installation manual calls for — this calculator reports consequences of a diameter you've already selected, not a diameter recommendation.
- Route to minimize elbow count where practical — each 90° elbow adds nearly as much equivalent length as several feet of straight run.
- Double-check outdoor unit position (same level / above / below indoor) carefully — the elevation rule is genuinely asymmetric, and getting the direction wrong flips which rule applies.
- Check your outdoor unit's nameplate or spec sheet for its compressor type (scroll/reciprocating, rotary, or two-stage) — this sets the real maximum length Goodman/Amana supports, and single-stage scroll/reciprocating allows significantly longer runs than rotary or two-stage equipment.
- If the outdoor unit is below the indoor unit, plan for an inverted suction trap regardless of length — it's always required in that configuration, not just past a threshold.
- This calculator is R-410A only — R-32 and R-454B systems (increasingly common as R-410A is phased down) need their own manufacturer-specific charge figures.
- Always perform a final refrigerant charge adjustment (subcooling/superheat check) after adding the calculated amount — this figure is a starting point, not a substitute for proper commissioning.
- Different manufacturers publish meaningfully different length and elevation limits for their own equipment — always cross-check against your specific installed or selected unit's own manual.
Common Mistakes
- Using equivalent length for the refrigerant charge calculation instead of actual straight length — the two figures serve different purposes and should not be swapped.
- Assuming the elevation rule is symmetric — an outdoor unit above vs. below the indoor unit triggers genuinely different requirements at the same height difference.
- Assuming the maximum length is the same for every compressor — a single-stage scroll/reciprocating system supports up to 250 ft equivalent, but a rotary or two-stage system is capped at 150 ft, a meaningful difference.
- Assuming the 80 ft elevation maximum applies to every above-indoor installation — it only applies to single-stage heat pumps; single-stage air conditioners have no stated hard maximum, and two-stage equipment is capped much lower, at 25 ft.
- Selecting "Same Level" for any small height difference without checking the actual number — it only applies up to 10 ft; beyond that, Goodman/Amana says to categorize the installation as Above or Below instead, each with different rules.
- Assuming any suction diameter offered for a capacity tier is approved for every compressor type — two-stage heat pumps have specific diameter restrictions (some blanket, some length-dependent) that single-stage systems don't.
- Assuming a liquid line solenoid is only a heat-pump concern — it's also required for air conditioners when the outdoor unit is below the indoor unit, per Goodman/Amana's own accessory tables.
- Applying this calculator's R-410A figures to an R-32 or R-454B system — refrigerant density differs, and the charge rate does not transfer.
- Ignoring elbow count entirely and using straight-line distance as equivalent length — this understates the real capacity derating on a routed, bent installation.
- Treating one manufacturer's elevation/length limits as universal — always verify against the actual installed or selected equipment's own manual.
- Skipping final subcooling/superheat verification after adding the calculated refrigerant charge, treating the calculated ounces as the final word.
Limitations
- All figures are Goodman/Amana's own published guideline (TP-107), not a universal industry standard. Other manufacturers (Carrier, Trane, Daikin, and others) publish meaningfully different length, elevation, and accessory thresholds for their own equipment — always verify against your actual installed or selected unit's own installation manual before finalizing.
- R-410A only. R-32 and R-454B (increasingly common replacements) have different refrigerant densities, and no consistent charge-rate figure was found for them — do not apply this calculator's refrigerant charge figure to a non-R-410A system.
- This calculator does NOT recommend a line set diameter — diameter selection is genuinely specific to your equipment's own spec sheet. Enter the diameter your equipment calls for; this calculator reports the consequences of that choice at your specific length.
- Compressor Type only covers three categories TP-107 itself publishes limits for: single-stage scroll/reciprocating, single-stage rotary, and two-stage. It does NOT cover inverter-driven, variable-capacity compressors — increasingly common on modern mini-splits and many current heat pumps — since Goodman/Amana's own guideline provides no length/elevation limits for that compressor category at all. If your equipment uses an inverter/variable-capacity compressor, none of these three options genuinely apply — defer entirely to that equipment's own manufacturer long-line guideline rather than picking the closest-sounding option here.
- Only long-radius elbow coefficients are modeled. Short-radius elbows add somewhat more equivalent length per elbow — using this calculator with short-radius fittings will understate true equivalent length slightly.
- 1/2in and 5/8in suction lines have no published elbow-loss data in the source table and are approximated using the 3/4in values — a small, disclosed simplification, not a fabricated number.
- Capacity multiplier is interpolated between documented 25 ft length columns (25-250 ft) and clamped at the table's own boundaries — very short or very long lengths outside this range use the nearest documented column rather than an extrapolated guess.
- Two capacity-multiplier table cells (30,000 BTU/3-4in/175ft and 60,000 BTU/7-8in/200ft) printed values that broke the smooth pattern of their row; this calculator adjusts them to match the surrounding values as an inferred correction, not a confirmed manufacturer erratum.
- No published refrigerant charge rate exists for a 1/2in suction line — that combination falls back to a liquid-line-only rate that likely understates the true additional charge needed.
- A single-stage heat pump's 80 ft above-indoor elevation maximum has named-model exceptions (some models rated to 200 ft) that are not modeled here, since they depend on the specific model, not on capacity or staging alone — check your unit's own manual.
- Does not model piston/AccuRater sizing changes for heat pump heating mode, TXV vs. fixed-orifice metering device differences, or specific accessory part selection — see your unit's own long-line application guide for those details.
- Does not verify local code/permit requirements or refrigerant handling certification requirements.
Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.