ACHR News reported that a Missouri ice rink replaced its ice rink refrigeration retrofit, which swapped an "aging R-22 refrigeration system" for ammonia as part of a $5.2 million renovation completed in five months. That is an industrial job with a budget most homeowners will never see. The reason behind it still matters for the air conditioner or heat pump in your yard, because the refrigerant in an older house decides how repairs are priced, documented and handled.
Why R-22 Is Still Around
R-22 is an HCFC. The United States stopped producing new R-22 on January 1, 2020, so the refrigerant left in older equipment comes from recovered stock, reclaimed material and whatever a supplier still has on hand. Many systems installed before the switch to newer refrigerants are still running on it. When one of them is low, the refill is a cost question, not a quick top-off, and you want to know that before a technician writes the quote.
Read the Nameplate First
Before you call anyone, find the data plate on the outdoor condenser and the indoor air handler or furnace coil cabinet. The label lists the refrigerant type and the factory charge, and the model number tells a tech how the system was built. Photograph both plates and write the numbers in your maintenance file. If the label is worn or painted over, a certified technician can confirm the refrigerant from pressures and temperatures, but that is a service call, not a homeowner job.
What Your Multimeter Can and Cannot Tell You
A meter will not identify refrigerant. It can do useful work before the visit, though. Check that the condenser is getting line voltage at the disconnect, and test the run capacitor with the meter's capacitance setting after discharging it safely. If the unit has power and a sound capacitor, the problem may be in the refrigerant circuit, and that is worth stating clearly when you call. If the disconnect is dead, you have saved a diagnostic fee and a day.
Do Not Vent It
Federal rules under the Clean Air Act require refrigerant to be recovered during service, and venting it to the air is prohibited. If a technician says the circuit must be opened, ask how the refrigerant will be recovered, what amount was removed and what was added. The service invoice should show the refrigerant type and the pounds charged. Keep that invoice with the nameplate photos, because it is the record a future buyer or technician will ask for.
The Ammonia Question
Ammonia is widely used in large industrial refrigeration, including facilities like ice rinks. It is efficient, and it is also toxic and can be flammable at high concentration, so those plants are designed around ventilation, leak detection and trained operators. The rink project is a commercial retrofit with engineering behind it. Ammonia is not a drop-in for a residential split system, and a homeowner should never try to convert a house system to it. If a bidder suggests it, treat that as a red flag.
Price the Two Paths
If the system is old, compare two options. One is repairing a leak and recharging with recovered or reclaimed R-22, which keeps the current equipment running but may not be a long-term answer. The other is replacement with equipment built for a current refrigerant. Ask every bidder to write the refrigerant type, the charge amount, the leak test method and the warranty terms into the quote. Compare the efficiency ratings on any replacement unit, and schedule the inspection before peak season so you are not deciding in the middle of a heat wave.
If an older adult lives alone and the air conditioner is the only cooling in the house, family members sometimes arrange non-medical in-home support for older adults in St. Louis so someone can check the thermostat and report a warm house quickly. That helper can watch the room temperature and make the call, while the repair decision stays with the family and the licensed contractor.