Dear Angie: I have an old heat pump air conditioner with R-22 refrigerant that leaks out periodically. I've heard of contractors using a leak sealant to correct this problem. Are sealants effective? Also, I've seen some newer models claim to be 30 percent more efficient compared to my 15-year-old unit. Is this true? I've also read that the R-410A refrigerant for newer units has a much smaller molecule size, which makes it leak faster. Is this true? If so, are the units built better to compensate for this? — Al B., Bardstown
Dear Al: Some heating and cooling contractors do offer a refrigerant leak sealant; however, many do not. Sealants can sometimes be effective in addressing small leaks, but they are considered a short-term fix, rather than a long-term solution. Many contractors won't use these sealants, because they can block passages and openings in the system, which could do more harm than good.
All that said, you really need to examine why your air conditioning system is losing refrigerant. A properly working system should never leak refrigerant. If your system is losing refrigerant, there's a mechanical problem that you need to address. Refrigerant that leaks into the atmosphere is an environmental hazard, and as the owner, you are responsible for ensuring that your a/c unit is not leaking.
Loss of refrigerant can often be traced to a leak in the evaporator coil or the outdoor condenser coil. This can be fixed only by replacing the part. For a 15-year-old system, that's probably not an investment worth making. The unit is probably less efficient than a newer unit, and the R-22 refrigerant you'll need to replace is increasing in cost as it is being phased out of production.
As for whether a new unit can be 30 percent more efficient than an older unit, that will depend on the efficiency, or seasonal energy efficiency ratio rating, of the new unit compared to the existing unit.
SEER ratings have increased quite a bit over the past 15 years. A 13 SEER was once considered efficient, but it is now the minimum rating allowed on newly manufactured units. The SEER rating on the most energy-efficient units can now reach into the mid-20s. The higher the SEER rating, the less electricity the system requires, thus making it more efficient. Upgrading from a 10-SEER to a 13-SEER unit would equate to a 30 percent increase in efficiency.
Although new systems that use R-410A do operate at higher pressure, there is no clear evidence to suggest that the refrigerant leaks faster than R-22. HVAC contractors I've talked to say the R-410A units are built to handle that higher pressure.
I recommend that you have a qualified heating and cooling company come out to assess your air conditioner to determine where it's leaking and whether it's worth repairing or replacing.