RefrigCharge vs Refrigerant Charge Calculator

Built for HVAC service techs and install crews who need subcool / superheat diagnosis on the roof - not a dashboard you log into. WHAT IT DOES Computes measured subcooling and superheat from your gauge readings, compares them against per-refrigerant target windows, and tells you whether the system is undercharged, overcharged, or showing airflow issues. Charge adjustment advice differs for TXV vs. piston / cap-tube metering, matching the field workflow. REFRIGERANTS SUPPORTED - R-410A - R-22 - R-134a - R-404A - R-407C INPUTS - Refrigerant type (picker) - Metering device (TXV or Piston / Cap Tube) - Liquid line temperature - Condensing saturation temperature - Suction line temperature - Evaporating saturation temperature - °F or °C toggle RETURNS - Measured subcooling vs. target (color-coded: green within ±3°F, red outside) - Measured superheat vs. target (color-coded) - Diagnosis: undercharged, overcharged, normal, or airflow issue - Charge adjustment advice: ADD, REMOVE, or CORRECT - Adjustment basis: subcool for TXV, superheat for piston WHY THIS APP, NOT THE FREE ONES - Math is shown - measured minus target, with the per-refrigerant windows visible. - Status at a glance - color-coded so you do not have to do mental arithmetic on the ladder. - Works offline - RF-shielded basements, attics, and roofs. Always available. - No login. No ads. No telemetry. No subscription. PRICING $4.99. Pay once, own it. Lifetime access on iPhone, iPad, and Mac via Family Sharing. NOT A SUBSTITUTE FOR The manufacturer's charging procedure for your specific equipment. The equipment data plate's nameplate charge. Calibrated gauge sets. This app gives you a directional read - verify against the OEM service manual before adjusting.

Refrigerant Charge Calculator — built for working HVAC and refrigeration techs. Open it at the condenser, pick the refrigerant, type your superheat or subcooling, and get a clear field verdict: Add, Hold, or Remove. No classroom theory. No 20-step wizards. Just the number you need, in the unit you work in. WHAT YOU CAN DO • Charge check by superheat — fixed-orifice, piston, or cap tube systems, with target ranges interpolated from indoor wet-bulb and outdoor dry-bulb • Charge check by subcooling — TXV and EEV systems, measured against the nameplate target • Line-set charge estimation — add-a-length and long-line corrections done in seconds • Pressure–Temperature reference — 1-psig precision, with bubble, dew, and mid-point readings for zeotropic blends (glide shown explicitly) • Altitude-corrected pressures — auto-detected from your location, or set the elevation by hand • Saved jobs — address and GPS coordinates tagged from the map • One-tap PDF job sheets — header, readings, verdict, notes — ready to email to the building owner, property manager, or warranty adjuster • Unit toggles everywhere — °F / °C, psig / bar, imperial / metric line sets • Fully offline — attics, basements, rooftop curbs, mechanical rooms with no signal REFRIGERANTS COVERED — 86 TOTAL A2L low-GWP (2025 compliant) R-32 · R-454A · R-454B · R-454C · R-452B · R-457A · R-1234yf · R-1234ze(E) · R-1234ze(Z) · R-1243zf · R-1336mzz(E) HFC workhorses R-410A · R-410B · R-134a · R-404A · R-407A · R-407C · R-407F · R-448A · R-449A · R-449B · R-452A · R-507A · R-513A · R-515B Legacy and service blends R-22 · R-11 · R-12 · R-123 · R-124 · R-125 · R-500 · R-502 · R-417A · R-421A · R-422A · R-422B · R-422C · R-422D · R-427A · R-438A · R-453A Naturals R-290 propane · R-600a isobutane · R-717 ammonia · R-744 CO₂ · R-1270 propylene Plus 30+ less-common 400-series blends you won't find on a pocket slider — full list browsable inside the app. REFRIGERANT DETAIL PAGES Every refrigerant comes with the data you actually look up on the job: • GWP and ASHRAE safety class • Tank color code • Occupational Exposure Limit (OEL) • Temperature glide for blends • Critical point and molecular weight • Common applications and replacement notes WHO IT'S FOR • Residential and light-commercial HVAC service techs • Refrigeration techs working supermarket R-744 racks and R-290 cases • A2L installers catching up on R-454B and R-32 • Apprentices studying for EPA 608 and ESCO certification • Shop owners who want every tech reading the same charge verdict WHY TECHS CHOOSE IT • Offline-first — calculations run on device, no spinning loader in a crawlspace • No account required — open the app, run the math, close the app • Verdict first, numbers after — the screen tells you what to do before making you scroll • Your jobs stay on your phone — nothing leaves the device without a tap from you • Built by listening to techs, not classroom instructors Privacy Policy: https://docs.nikitin.fyi/com.hvacrcharge.app/privacy-policy.html Terms of Service: https://docs.nikitin.fyi/com.hvacrcharge.app/terms-of-service.html