Calculators
Refrigerant Line Set Charge Calculator
Calculate the additional refrigerant needed for a line set longer than the factory charge allows.
- Runs in your browser
- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Commissioning a new split system
- Planning long line set installations
- Technician training
- Checking installer work
About this tool
What the Refrigerant Line Set Charge Calculator does
Split air conditioners and heat pumps are shipped with enough refrigerant for a set line length, often around 15 feet. Longer line sets need extra charge, specified by the manufacturer in ounces per foot of liquid line, which depends on the line diameter. Final charge is then verified by subcooling or superheat.
It also works as a refrigerant charge calculator.
Formula
- Extra length = actual length − factory-charged length
- Additional charge = extra length × ounces per foot
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| Actual line set length | 35 ft |
| Length covered by factory charge | 15 ft |
| Additional charge per foot | 0.6 oz/ft |
| Result | Value |
|---|---|
| Additional refrigerant | 12.0 |
| In pounds | 0.75 |
| In grams | 340 |
| Line set beyond factory length | 20.0 |
How to read the result
Always confirm the final charge with the manufacturer’s subcooling or superheat target once the system is running.
Some systems require removing charge for very short line sets; check the manual.
For planning only. Electrical, gas and refrigerant work must follow current codes and be carried out or checked by a licensed professional.
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Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
It depends on liquid line diameter and refrigerant; the installation manual gives the figure.
Many units are precharged for around 15 feet, but this varies by model.
In the US, technicians must hold EPA Section 608 certification; other countries have similar rules.
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