PT charts by refrigerant
Looking for a free PT chart? Use the chart for the refrigerant you are working with, including PT chart resources for R-454B, R-32, R-410A, R-22, R-134a, and R-404A. If you are handling A2L refrigerants, start with the A2L refrigerant handling guide.
Superheat and subcooling calculator
Use the superheat and subcooling calculator to work through field readings and estimate whether a system is running as expected. It is a fast way to answer how to calculate superheat without doing the math by hand.
Leak rate calculator
Use the leak rate calculator to estimate leak rate from your measured loss over time. It is meant to help with the question of how to calculate leak rate before you decide what to inspect next.
Charge amount basics
Refrigerant charge depends on the equipment and the manufacturer instructions, so start with the nameplate and the service information before making any adjustment. For a quick home base, see the HVAC Refrigerant Log home page and get the app page, then return here for calculator links and reference charts.
Line set length can affect the final charge amount, so follow the equipment guidance for any adjustment notes tied to the installed line set.
Reference only. Verify with manufacturer data and gauges. Follow the manufacturer chart and EPA rules. This site is not an approval from EPA.