Originally Posted By: KrisZ
Originally Posted By: Rick in PA
Me? I leave it on. I try to run the A/C once a month or so over the winter. That circulates the oil, which I believe helps to keep the freon from leaking out.
Then either you are very lucky you did not damage your compressor or the temperatures weren’t low enough to do any damage.
Unlike automotive AC systems, which have rubber seals and o-rings that can dry out if not used, home A/C systems have no such things because all connections are brazed, therefore it doesn't need to be run in winter.
Also, unlike car's A/C, when the temperature is really low, there is a chance that the freon will not vaporize and may be ingested by the compressor in its liquid form, in which case the compressor is toast.
I think more expensive, top of the line A/C units have various safety measures to prevent that, but generally it is still not a good idea to run the compressor during winter.
I only run it during warm spells during the winter. Those occasional mild, sunny days when the temperature rises above 50F. Also, in the afternoon, sunshine plays on the condenser further warming it. It only gets run for 10 or 15 minutes. Once a month or so. I probably should have been more specific on the conditions when it is run.
While a home air conditioning system may be "sealed", there are potential leakage areas such as where wiring enters the compressor, fill fittings, what appear to be compression fittings. There's also the matter of metal porosity, micro fractures in joints, etc. No system is perfect.
When we first moved into this house 10 years ago, I did not run the system over the winter. In the spring, it had to be recharged. Since then, I run it occasionally and have not had to have it recharged since. I could get it checked, but they probably wouldn't find anything (remember it's run fine for 8 or 9 years now).
I understand the differences between automotive and house A/C, but there are also similarities. Many years ago, it was a spring ritual to have the automobile A/C recharged, a lot of folks would have to have it done. At some point manufacturers altered the system design to activate the A/C system when the defroster is turned on, primarily to provide dry air for the defroster. As a result the refrigerant oil is regularly circulated during the winter. I believe this has a benefit of reducing freon loss. I haven't had to have an automotive A/C system recharged in decades.
I'm in the camp that occasional running of machinery (under the appropriate conditions) is better than not running it.
