Heat Pump Leaking Refrigerant - Is my Heat Pump Low on Refrigerant? I get this question a lot from both my customers and my site visitors. They tell me every year a technician comes out and pumps a few pounds of refrigerant into their unit and it’s good again for another year. A refrigerant leak for an air source heat pump is not uncommon. Or is it? Let us explore the question a bit further and see what really happens when you refill the unit over and over again, year after year.

Heat Pump Leaking Refrigerant

So you ask yourself, “Is my Heat Pump Leaking Refrigerant“? For a heat pump, it can mean it costs you a ton of money in the wintertime because your system will run off the backup heat most of the time. Backup heat is more expensive than running the condenser to provide heat, provided the temperature outside is not extremely cold. The colder it gets outside, the less efficient a hump pump is at providing heat for your home. If you have electric backup heat, the cost is expensive.

If the heat pump is leaking refrigerant then the leak should be fixed or replacement considered. We’ll explore these decisions if your heat pump is leaking refrigerant.

If you have a dual fuel heat pump system then you have a gas furnace for backup heating and the efficiency of that depends on the AFUE or efficiency rating. The AFUE rating only applies to the efficiency of the gas furnace and not the heat pump. Therefore, a refrigerant leak in your heat pump can cost you more energy costs (energy efficiency) and in future heat pump repair costs.

Either way, it’s more expensive to heat with the backup heat than it is for the condenser to provide the heat for most of the heating season - again as long as the temperature is not too cold ~30°F. That does not apply to geothermal heat pumps. All the geothermal heat pumps I worked on or serviced did not have backup heat. I am not aware of any geothermal heat pump system that has backup heat. There may be some out there but not to my knowledge.

The Low Refrigerant Cycle | How to Tell If Heat Pump is Low on Refrigerant

Most of the time, the homeowner will recognize a problem with their heat pump in the Spring. That is the time when they turn it to the cooling mode. It is then they see the heat pump is not cooling as it should. This also means they were running it in heating mode with only the backup heat providing heat. They did not know there was a problem because the heat was coming from an alternate source. Yes, a refrigerant leak can be detrimental in more ways than one.

This alternate source, the backup heat, was costing them more money. You may discover the refrigerant leak problem by recognizing a frozen evaporator coil. That results in low airflow. A frozen air conditioner will cause low air flow and no cooling for a heat pump system. So this cycle goes on year after year until the heat pump suffers a catastrophic failure or refrigerant leak. Then it is time to either repair or replaces it.

Recognizing Low Refrigerant Signs for a Heat Pump

It is typically only in the warmer weather in spring or summer does the homeowner recognize there is a problem. They turn it to cool, and the system either doesn’t cool, or it freezes up. Sometimes at the evaporator coil and sometimes at the pipes on the condenser, or both. During the winter, the alternative or backup heat has been providing the heat. As noted above, likely costing more to heat with backup heat unless they have a high AFUE gas furnace dual fuel system. What are the signs a heat pump is low on refrigerant? How do you tell if a heat pump is low on refrigerant?

1. When you have electric backup heat, and you notice higher than usual electric bills.
2. If you have a dual fuel heat pump and you notice a higher than usual gas bill.
3. You notice the thermostat is constantly behind on keeping up with the set point in the heating season.
4. You see ice on the evaporator coil or the pipes at the outdoor condensing unit.

Where’s the Heat Pump’s Refrigerant Leak? Replace or Repair? | Heat Pump Leaking Refrigerant

A vast majority of the refrigerant leaks I’ve repaired happened to be the accumulator was rusted out. However, a refrigerant leak can be anywhere in the system from a leaking shraeder core to an evaporator coil to any other refrigeration component in the system. The problem with the accumulator is they are made out of steel and are in the condenser. Accumulators are subject to all weather conditions and eventually rust out and start leaking refrigerant.

It’s not a cheap repair, but it’s not very expensive either. All the refrigerant needs complete recovery, and then the old accumulator is cut out, and a new one is piped in. Fixing a refrigerant leak requires an HVAC technician knowledgeable in refrigeration and proper practices.

If the heat pump is very old, say over 12 years old then I would consider replacing it for two reasons. First is the cost of the repair versus what you could put into a new system that will be far more efficient. Any refrigerant leak also means the oil has been leaking out of the system. Most residential systems have hermetically sealed compressors. That makes it nearly impossible to add oil to the system to replace what was lost.

Eventually, that loss of oil will take its toll on the mechanical parts of the compressor, and they will fail. A compressor is a costly repair. That is why serious consideration should be made for replacing rather than repairing. Why spend a lot of money on the old system when it is likely it will fail soon after the repair?

Replacement Considerations | Heat Pump Leaking Refrigerant

The accumulator is the component bottom right.

If you decide to replace; then, some considerations need addressing. If the system is the old R-22 refrigerant system, then the line set needs to be replaced. The old line set can be flushed; however, it is much better if the line set gets replaced. The oil from the old system will not mix with the oil from the new system.

The old system (R-22) uses mineral oil while the new R-410A systems use synthetic oil. If the old oil mixes with the new oil, it can create a big problem, this will cause the new system to fail. That is why I recommend replacing the old line set. That and pipe size will likely be different for the new system. The new system will likely require larger piping than the old one.

Next is the efficiency level of the new system. Choosing a system that is far more efficient is always better than a system that is not so efficient. For help in choosing the right system and contractor see our HVAC Consumer Buyers Guide.

Repairing Leak Considerations | Heat Pump Leaking Refrigerant

If they find a refrigerant leak in the accumulator, that does not mean you don’t have another leak elsewhere. Or even if finding the leak in another component. The technician should do a high-pressure nitrogen leak test before finally declaring the system leak-free. Another way to test this is by using a micron gauge. These are tools used when they are pulling a vacuum on the system. A vacuum is necessary on all refrigeration systems to remove air and other impurities from the refrigeration system.

This is done before recharging the heat pump with new refrigerant. I use both methods before recharging any refrigeration system. It is a part of the triple evacuation process that should be done before any refrigerant is reintroduced into the refrigeration system. It is a part of being very thorough, and the results are excellent if done properly.

Conclusion | Heat Pump Low on Refrigerant

Finally, we hope this helps answer your questions about heat pump refrigerant leaks. Hopefully, it enlightened you to a small problem before it becomes a big problem. Happy heating and cooling!

Heat Pump Leaking Refrigerant Question

Frequently Asked Questions from our readers about heat pumps leaking refrigerant issue:

Resource: The Home Comfort Book: The ultimate guide to creating a comfortable, healthy, long lasting, and efficient home