Field guides
The calculations behind the calculators — written the way a senior tech would explain them on the job. Learn the method by hand first; the app just makes it a three-tap job.
The formula, where to clamp, and target ranges for fixed-orifice and TXV systems.
Read the guide →Typical 10–12°F targets, when the nameplate overrides, and what high or low readings mean.
Read the guide →Why TXV systems charge by subcooling, fixed-orifice by superheat — and why you read both.
Read the guide →Full pressure-temperature table with bubble and dew columns, plus how glide changes your readings.
Read the guide →Saturation table for R-32, how it compares to R-410A, and A2L handling notes.
Read the guide →Saturation temps, superheat and subcooling lookups, and the bubble/dew columns on blends.
Read the guide →400 CFM/ton standard air — when to run 350 in humid climates and 450 in dry ones.
Read the guide →Trunk and return sizes at 1,200 CFM, round-to-rectangular equivalents, and velocity limits.
Read the guide →The 20 BTU/sq ft cooling baseline, climate-zone heating table, and square-footage-to-tons chart.
Read the guide →Size off the nameplate MCA — not tonnage — with NEC 310.16 and 10/2 vs 10/3 explained.
Read the guide →MOCP vs MCA off the nameplate, typical 30–45A range, and the oversized-breaker red flag.
Read the guide →The 3% / 5% recommendation, the 2×K×I×D/CM formula, and a worked condenser example.
Read the guide →BTU load, duct sizing, and the unit converter are free. P-T charts, superheat & subcooling, and NEC wire sizing come with Pro — 3-day free trial, then $4.99/mo or $19.99/yr.
