HVAC/R field calculators
Field calculators that use the same equation-of-state data as the PT charts, so a superheat or subcooling result matches the chart for that refrigerant to the tenth of a degree. Every refrigerant tool covers all 62 refrigerants on the site and reads the correct column for blends: vapor (dew) for suction and superheat, liquid (bubble) for the liquid line and subcooling.
Each tool shows a worked result before you type anything, recalculates as you enter values, and works offline once the page has loaded. Gauge readings can be corrected for elevation. Where a result cannot honestly support a charge decision, such as a TXV system judged on superheat alone or a superheat test outside the conditions the CEC method allows, the tool says so instead of guessing.
Superheat calculator
Enter the suction pressure and the suction line temperature to get actual superheat. Add a target superheat on a fixed-orifice system and the tool tells you whether the charge is within the ±5°F installer tolerance.
Subcooling calculator
Enter the liquid line pressure and liquid line temperature to get actual subcooling. Add the manufacturer's target subcooling and the tool checks it against the ±3°F installer tolerance used for TXV and EEV systems.
Target superheat calculator
Enter the indoor return air wet bulb and the outdoor air temperature entering the condenser to get the target superheat from CEC Table RA3.2-2. Add your measured superheat to see whether the charge is within ±5°F.
PT calculator
Pick a refrigerant and type a gauge pressure to get its saturation temperature, or type a temperature to get the pressure. Blends show both the dew point for suction and superheat and the bubble point for the liquid line and subcooling.
Temperature glide calculator
Pick a blend and enter a gauge pressure to get its bubble point, dew point, midpoint and the glide between them. The table below the tool lists the glide of every blend at 40°F evaporating and 100°F condensing.
Duct sizing calculator
Enter the airflow in CFM and a design friction rate in inches of water per 100 ft. You get the round duct diameter, the velocity and friction at the next whole-inch size, and rectangular ducts with the same friction.
Line set charge calculator
Enter the liquid line size, the actual line set length and the length the factory charge covers. You get the ounces to add or remove, which you weigh in and then confirm by subcooling or superheat.
Airflow (CFM) calculator
Enter the sensible heat in BTU/h and the supply and return air temperatures to get airflow in CFM. Add the elevation and the tool reduces the 1.08 factor for thinner air.
Pressure converter
Enter a value and pick its unit to see it in psig, psia, kPa and bar (gauge and absolute), MPa, inches of mercury vacuum and microns. Add your elevation so gauge readings convert against the local air pressure.
Psychrometric calculator
Enter the dry bulb and one second reading (wet bulb, relative humidity or dew point), plus elevation if you are well above sea level. You get the full moist-air state, including the indoor wet bulb a fixed-orifice target superheat needs and the dew point for condensation checks.
Static pressure calculator
Enter the supply and return static pressure readings in inches of water column and the rated external static from the nameplate. You get the total external static pressure, its percentage of the rating and, if you add filter and coil drops, how much is left for the ducts.