R-22 (Legacy HCFC)
R-22 Superheat & Subcooling Calculator
Check charge on legacy R-22 systems with the calculator preloaded for the old Freon workhorse. Full PT chart, TXV and fixed orifice targets, and honest guidance on when a 16-plus-year-old system is worth another pound of the most expensive refrigerant on the truck.
R-22 Pressure-Temperature Chart
| Pressure (psig) | Sat. Temp (°F) |
|---|---|
| 1 | -40°F |
| 5 | -30°F |
| 10 | -20°F |
| 17 | -10°F |
| 24 | 0°F |
| 28 | 5°F |
| 33 | 10°F |
| 38 | 15°F |
| 43 | 20°F |
| 49 | 25°F |
| 55 | 30°F |
| 62 | 35°F |
| 69 | 40°F |
| 76 | 45°F |
| 84 | 50°F |
| 93 | 55°F |
| 102 | 60°F |
| 111 | 65°F |
| 121 | 70°F |
| 132 | 75°F |
| 144 | 80°F |
| 156 | 85°F |
| 168 | 90°F |
| 182 | 95°F |
| 196 | 100°F |
| 211 | 105°F |
| 227 | 110°F |
| 243 | 115°F |
| 260 | 120°F |
The anchors: 69 psig is a 40°F evaporator and 196 psig is a 100°F condenser. If you spend most of your week on R-410A, recalibrate your instincts before touching an R-22 system; 120 psig suction is normal on R-410A and wildly overcharged territory on R-22.
R-22 Target Superheat & Subcooling
| Metering device | Target superheat | Target subcooling | Charging method |
|---|---|---|---|
| TXV | 10–18°F | 10–16°F | Charge by subcooling; the TXV holds superheat |
| Fixed orifice (piston) | 5–25°F | 4–12°F | Charge by superheat from the manufacturer charging chart |
Note the targets sit a couple degrees higher than R-410A norms. R-22-era equipment also used fixed orifices far more often than modern gear, so expect to charge by the superheat chart more frequently on these calls.
Servicing R-22 in 2026
R-22 was the residential standard for half a century until the HCFC phase-out ended new R-22 equipment in 2010 and new refrigerant production and import on January 1, 2020. Every pound sold since then comes from reclaimed or previously produced stock, which keeps prices high and climbing. The systems still running on it are all 16 years old or older, most on mineral oil, many with fixed-orifice metering, and every one of them is a servicing-only proposition: keep the existing charge healthy or plan the replacement.
That economic reality changes how you use superheat and subcooling on these calls. On a modern system, a slightly low charge is a trim; on R-22 it is a decision point. Confirm the diagnosis with both readings before committing refrigerant, quote the leak search with the top-off, and put the repair-versus-replace numbers in front of the customer while the gauges are still on the ports.
R-22 Charging Notes
R-22 is a pure single-component HCFC with zero glide, so PT work is simple and vapor charging does not fractionate anything. It runs on mineral oil, which matters mostly when retrofit blends enter the conversation: R-407C needs a full oil conversion to POE, while blends like R-438A tolerate residual mineral oil. Never mix a retrofit blend into remaining R-22; recover the full charge, follow the retrofit procedure, and relabel the equipment.
On charging technique, nothing exotic: charge to subcooling on the minority of R-22 systems with a TXV, and to the manufacturer superheat chart on fixed-orifice systems using outdoor ambient and indoor wet bulb. Verify airflow first. Two decades of dust in a blower wheel and a half-plugged evaporator produce the same low suction pressure a leak does, and the difference is a free fix versus a very expensive pound of refrigerant.
Worked Example: Aging R-22 Condenser, Suspected Leak
A 2008 R-22 split system with a TXV, cooling poorly on an 88°F day. Field readings: suction pressure 58 psig, suction line temperature 55°F, liquid pressure 168 psig, liquid line temperature 84°F.
Saturated suction temp at 58 psig ≈ 32°F
Superheat = 55°F − 32°F = 23°F
Saturated liquid temp at 168 psig = 90°F
Subcooling = 90°F − 84°F = 6°F
Diagnosis: Superheat 23°F is well above the 10–18°F TXV target and subcooling 6°F is below the 10–16°F target. High superheat with low subcooling is the low-charge signature: the evaporator is starved and the condenser has no liquid seal. On an 18-year-old system, electronic leak-search the evaporator coil and service valves before adding anything, then have the repair-or-replace conversation with the refrigerant quote in hand.
R-22 Service FAQs
What is normal superheat for R-22?
With a TXV, target superheat for R-22 is 10-18°F. With a fixed orifice, which is common on R-22-era equipment, target superheat swings widely with conditions (roughly 5-25°F) and must come from the manufacturer charging chart using outdoor ambient and indoor wet bulb. Charging an old piston system to a single guessed superheat number is one of the classic R-22 field errors.
What is normal subcooling for R-22?
Target subcooling for R-22 with a TXV is 10-16°F, measured at the liquid line off the condenser. On the many fixed-orifice R-22 systems still running, subcooling typically lands around 4-12°F, but superheat is the charging indicator on those systems and subcooling is a cross-check.
Can I still buy R-22?
Production and import of virgin R-22 ended January 1, 2020 under the Clean Air Act HCFC phase-out. Only reclaimed and previously produced stock remains, sold to EPA Section 608 certified technicians. Supply keeps shrinking and per-pound prices are several times what comparable refrigerants cost, which is why leak repair or system replacement usually beats repeated top-offs.
Is it illegal to run an R-22 system?
No. Owning, running, and servicing an existing R-22 system is completely legal. The phase-out stopped new production and import of the refrigerant, not the use of existing equipment. What is illegal is knowingly venting it: R-22 must be recovered with certified equipment.
Can I replace R-22 with R-410A in the same system?
No. R-410A runs roughly 60 percent higher pressures than R-22; an R-22 compressor, coils, and line components are not rated for it, and R-410A requires POE oil where R-22 systems hold mineral oil. Moving to R-410A or an A2L refrigerant means replacing the equipment, not the refrigerant.
What refrigerants can replace R-22 in an existing system?
Retrofit blends exist: R-407C (requires flushing mineral oil and converting to POE) and drop-in style options like R-438A (MO99) or R-422D that tolerate some mineral oil. All lose a little capacity, most add glide, and the TXV or orifice may need adjustment. On equipment already 16+ years old, price the retrofit honestly against replacement before committing.
Should I repair or replace an R-22 system?
Run the math on age and refrigerant cost. Every R-22 system is at least 16 years old in 2026, refrigerant runs several times the cost of R-410A per pound, and a major component failure (compressor, coil) rarely justifies the spend. A minor repair with a tight, healthy circuit can buy a season or two; a leaking evaporator on a 20-year-old condenser is a replacement conversation.
Other Refrigerants & Related Tools
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All-Refrigerant Calculator
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A2L Charge Limit Calculator
Maximum A2L charge for a room, or minimum room area for a charge, per UL 60335-2-40 and ASHRAE 15.2. Covers R-454B, R-32, and 6 more refrigerants.
EPA Refrigerant Leak Rate Calculator
Topping off a 15+ lb system triggers a leak rate calculation under 40 CFR 84.106 as of January 1, 2026. Run the EPA math and check the thresholds.
BTU / HVAC Load Calculator
Size the system by climate zone, insulation, windows, and duct location with automatic tonnage recommendations.
Quoting the replacement? Size it right this time.
R-22-era systems were routinely oversized, and copying the old tonnage copies the mistake. Run the load by climate zone, insulation, and windows before writing the quote.