Home › AC Refrigerant › How to read your data plate
Everything the rest of this section estimates, your data plate simply states. It takes about thirty seconds to find and is the difference between a probability and an answer.
Where it is
On the outdoor condensing unit — the box outside with the fan. The plate is a metal, foil, or printed label, usually on the side panel, sometimes behind or beside the electrical disconnect. You do not need to open anything or remove any panel to read it.
If it faces a wall or fence, a phone camera held around the side and the flash on will usually get you a readable photo without moving anything.
What to look for
| Field | What it tells you |
|---|---|
| REFRIGERANT | The line you came for. It will read R-22, HCFC-22, R-410A, R-32, or R-454B. This is the answer, full stop. |
| FACTORY CHARGE | Often given in pounds and ounces (for example “8 LB 4 OZ”). This is the charge for the outdoor unit with a standard line-set length, not necessarily your whole system’s total. |
| MODEL NUMBER | Usually encodes capacity. A group like 024, 036, or 048 means 24,000, 36,000, or 48,000 BTU, which is 2, 3, and 4 tons respectively. |
| SERIAL NUMBER | Most manufacturers encode a manufacture date, though the format varies by brand. Often the first four digits are week-and-year or year-and-week. |
| VOLTS / PHASE / RLA / LRA | Electrical ratings. Not needed for refrigerant questions. |
| A2L flammability marking | Present on R-32 and R-454B equipment, absent on R-22 and R-410A equipment. A useful confirmation. |
Check for a second sticker
This is the step most people skip. If a system was retrofitted, the original nameplate still says what it was built with, and a separate service sticker records what is actually in it now. If the plate says R-22 and a sticker says R-407C or MO99, the sticker is the truth.
If the plate is unreadable
Weather and sun destroy these labels, particularly on older units. Options, in order:
- Check the indoor air handler or furnace — the matched coil often has its own label.
- Look for the model number anywhere on the unit and search the manufacturer’s documentation for it.
- Check paperwork from the original installation or your last service invoice.
- Ask your technician to identify it and show you where they got it. They have to know before working on the system anyway.
Failing all of that, estimate from the year and system type — with the confidence caveats that come with it.
Related: Find my refrigerant · Refrigerant by year · Estimate my charge
Frequently asked questions
Where is the data plate on an AC unit?
On the outdoor condensing unit, usually a metal or foil label on the side panel, sometimes near the electrical disconnect. You do not need to remove any panel to read it.
What does factory charge mean on the label?
The amount of refrigerant the outdoor unit was charged with at the factory, for a standard line-set length. Your system total may be higher if the line set is longer than that standard length.
How do I tell the age of my AC from the serial number?
Most manufacturers encode a manufacture date in the serial, commonly in the first four digits as week-and-year or year-and-week, but the format varies by brand. Look up your specific manufacturer’s serial format.
Sources & verification
✓ Verified against a manufacturer, regulator, or standards source
- EPA, “Homeowners and Consumers: Frequently Asked Questions” (HCFC phaseout) — epa.gov
⚠ Provisional — market-survey estimate, not a manufacturer or regulator citation
- Serial-number date encoding varies by manufacturer and is described in general terms here rather than as a per-brand rule.
Last reviewed 2026-08-31. How we verify what we publish →
