When I do A/C work whether it be R12 or
R134a I run a VOV [Variable Orifice Valve] regardless.
All of this discussion of refrigerant replacements is all well and good
but here is the catch, most of us are doing work on our own cars or
people's cars where the envrionment is tightly controlled. I don't
think any insurance company in NC is going to write me business
insurance that will cover me putting propane into someone's car. So
what are my choices?
R12 - Dichlorodifluoromethane
The original refrigerant gas of choice and mainstay of most cars until
the 1994 model year. Now running $40-50 per pound. New virgin
production ceased on Jan. 1, 1996 though a few bootleg countries are
making it. However as the number of R12 vehicles on the road needing
R12 recharges dwindles supplies & costs should stabilize for the
near long term.
Advantages: Cools really good; most all cars from when a/c first was
available until 1994 had R12 systems so a/c equipment was designed to
run efficiently on it.
Disadvantages: Supply and Cost while still available recharges are
R134a - Tetrafluoroethane
OEM replacement, all cars (I believe so) from the 1994 model year on
carry R134a. Smaller molecules than R12, smaller cooling capacity than
R12 runs at higher temp & pressures than R12 especially in
converted systems. Preferred convertible refrigerant due to
availability, industry and liability acceptance. Recommended use of VOV
for performance. $6 per can.
Advantages: OEM acceptance; industry acceptance; relatively cheap
(compared to R12; adequate supply and distribution for home or
Disadvantages: Poorer performance especially in converted systems; may
leak out of older conversions; performance can be mitigated by use of
R22 - Chlorodifuoromethane
Mainly used for industrial and home appliance applications. I have seen
this used in automotive applications but its closely linked to R12 and
thus going out of favor. Costs and supplies are sometimes problematic
like R12 but not as bad. Still in production but being phased out. $76
Advantages: Kissing cousin to R12 and thus wide acceptance in
Disadvantages: Same as R12 though supply and costs are not at R12
levels yet. Industrial use so industry acceptance and liability in
automobiles is minimal.
- Similar to R502 blend of
R22, R125, R143a used in industrial applications for heavy duty
cooling. Production slated to cease in 2020. Advantages are that it is
in use and cools really good disadvantages confined mainly to
- Blend of R22, R124,
R142a closely resembles R12. Production slated to cease in 2020.
Preferred industrial conversion refrigerant. Advantages like R134a for
cars industrial acceptance, OEM acceptance, cost and availability.
Disadvantages acceptance in auto a/c systems not widespread.
- Blend of R125, R143a,
R134a. Closely resembles R502 and the long term replacement for R408a.
Slightly less efficient than R502 and R408a. Industrial and OEM
acceptance. New industrial and commerical equipment slated to have OEM
R404a 2006. Advantages same as R408a, disadvantages it hasn't reached
acceptance in automotive industry yet. $275 25lb cylinder.
'AUTOFROST' EPA certified for automotive use; miscable with mineral oil.
Performance comparable to R12 in converted vehicles. It returns oil to
the compressor. Runs about $20 per pound.
is a Drop in
replacement for R134a. System can be topped with CoolTop without
removing R134a. Manufacturer claims will lower temps 10 degrees. I
wonder what CoolTop and a VOV will perform. Has a patented chemical
that isolates moisture. Cans are $18.
Johnsen's biggest claim is they make a lot of a/c handling equipment.
The things that drive what I put in people's cars is:
3) Material Handling
4) Future Serviceability
The biggest problems I have outside of R12 & R134a is that if I put
something like FREEZE 12 in a customer's car they drive off and good
luck finding someone who uses the alternative. I *know* of only 3 shops
in Charlotte that have the necessary equipment to regularly and legally
service anything besides R12 & R134a. Then try and explain what
408a is to a customer who cannot fill their own tires... I would be
curious to see what alternatives work with VIR & STV & hot gas