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Question DetailsAsked on 7/12/2017

how much is the typical cost of converting an AC unit from R22 to 407C

I have an old AIR-EASE unit that gets used 10 days a year. I recently replaced the fan unit because it would freeze. Now the compressor overheats & shuts down. Other than that the unit runs & sounds fine. I live in Aurora, il.

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1 Answer


Well, say 2-3 hours at say $75-100/hr flushing and refilling (so probably 10-20# gas for that at $20-30/lb), $25 solvent, and with some units changing out the TXV valve for another $100-200, possibly change out drier/filter unit ($100) if existing is not right kind for the very moisture-sensitive lubricating oil in the R407C -

so I would say, for normal 5 ton or smaller unit, about $375-825 with no valve or drier unit changeout needed depending on gas charge and amount needed to flush and fill, to $575-1225 with the whole shebang needed on a larger size unit.

I would definitely get several bids, and be sure to ask how they are going to get the existing oil out of the unit - because mixing more than about 5% of old oil with new can cause the works to get gummed up.

This assumes your unit is rated for R407C - some units cannot tolerate it because the different type of lubricant (which is not actually an oil in the normal sense) will not protect the compressor, or because the unit seals will deteriorate in the different gas/lubricant - some unit seals blow out in short order after such a changeout.

You say an old unit - why change the gas out at all ? It is quite possible it will die before R-22 is no longer available, and if any leak is fixed just refilling with R-22 may well be cheaper than the conversion as long as you don't get a ripoff artist charging $100-200/# for Freon which costs about $25/# in contractor size bottles.


I would also reconsider where you are getting HVAC advice too. Replacing the fan because the unit froze up makes no sense at all - if the fan failed the unit would be overheating and failing to cool properly, not freezing up (unless you meant an air handler fan, not the condensor fan). And with the compressor overheating, sounds to be like you have a refrigerant leak (commonly the evaporator coil in older units) so it would be a real pity to drop a load of $ on an older unit and find out you are into another $1500 ballpark to replace the evaporator coil (if still available, which it might not be) - which would be getting your total cost into the range where a totally new R410a unit might be the better decision, or indeed if a suitable coil were not available might be the only choice. I would look at finding the cause of the overheating (likely low gas pressure from a leak) BEFORE sinking any other money into it.


One other thought - if only used 10 days a year, depending on your living it might make more sense to get an economical (few hundred $) portable or window air conditioner instead, for maybe significantly less to not more than the conversion cost. Or if only needed 10 days a year, depending on whether you use it due to the raw heat or because of the hot sticky humid days, perhaps a swamp cooler or even large fan might fill the bill for you, because evidently you do not need a lot of summer cooling to be comfortable.

Answered 3 years ago by LCD

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