May 12, 2025
Some of the most common HVAC repair issues point to a single issue that’s simple to address. Refrigerant sits at the core of nearly all heat pumps and AC units. As a system loses refrigerant, though, the components have to work harder to achieve the same levels of heating or cooling. Consequently, refrigerant loss is a common driver of high HVAC repair costs.
How Refrigerants Work
Refrigerant in an HVAC system operates within a closed loop. In other words, your heat pump or AC doesn’t consume refrigerant in the same way that something like a car would consume gas and oil. Instead, the refrigerant is a transfer medium for heat. If the system is in a cooling mode, such as an AC unit during summer heat, the refrigerant transfers the heat through the system to outdoor coils so it can release the unwanted heat. Likewise, the refrigerant in a heat pump captures latent heat from the outdoors and brings it inside.
The process involves a state change as the refrigerant converts from a liquid to a gas and back. The refrigerant can perform this loop for years on end in a closed system with close to no natural operating losses.
Understanding Refrigerant Loss
You might wonder how a closed loop can suffer losses. A miniscule amount will evaporate through the tubing due to a phenomenon similar to how tires lose air through their walls from nitrogen loss. However, a heat pump or AC has to be particularly old for these losses to amount to anything noticeable.
Instead, the main culprits for refrigerant losses are all forms of physical damage. For example, everyday operation vibrates the fittings of a heat pump or AC. As the fittings get looser from the vibration, more refrigerant escapes through the gaps.
Corrosion is another common cause. Weathering can lead to fittings, tubing, and coils rusting to the point that refrigerant escapes from tiny holes. Notably, HVAC units can also attract ant colonies whose activities will further corrode components.
Impacts can damage HVAC units to the point of refrigerant loss, too. Something as simple as a rock sent flying by a lawn mower into the condenser coils can lead to refrigerant losses even in brand-new units.
Metal fatigue also happens with age in an HVAC. Repeated heating and cooling cycles can weaken tubes, coils, connections, and other elements. As the metals thin, the process of natural evaporative loss increases because there’s less of a barrier.
You may have noticed that most of these problems trace to components that our HVAC technicians can easily replace. In many cases, the replacement process is even possible without significant additional loss of refrigerant. We can usually replace the parts and recharge the system, getting the HVAC’s performance as close to new as possible.
Spotting Signs of Refrigerant Loss
Requesting repairs early is the best way to prevent refrigerant loss from getting out of hand. Being a pressurized system, refrigerant lines can produce hissing or bubbling sounds if they aren’t properly charged. Modern HVACs circulate lubricants with the refrigerant, too. This means you may see oil stains or puddles where leaks are present.
The reduction in heat transfer can also cause a noticeable performance drop. While the system will work harder to try to make up the difference, there is a good chance it won’t be enough to provide the expected heating or cooling. You may also notice an increase in humidity during cooling cycles because the unit isn’t working well enough to help dry the air.
You might notice either shorter or longer cycles. Short cycles are a sign that the unit is overworked to the point that it is overheating and triggers an automatic shutdown. Longer cycles indicate that the system is overworked but not overheating.
Although it sounds counterintuitive, the HVAC’s coils may also collect ice. As system performance inhibits heat transfer, the coils may no longer be able to stay warm enough to prevent ice formation. Icing can even occur in AC units on the hottest days of the year.
The Consequences of Refrigerant Loss
Two big budget busters tend to arise from refrigerant loss. The one that hits homeowners all at once is a compressor failure. Your system’s compressor handles the main job of pressurizing the refrigerant enough to convert it to a gaseous state. Not only does this facilitate heat transfer, but it also encourages the refrigerant to flow through the tubes and coils.
If there is less refrigerant in the lines, the compressor has to work harder to achieve the same level of heating or cooling. This leads to increased wear and tear. Left unaddressed, this stress will eventually cause the compressor to weaken or fail.
Compressor failures are among the most expensive HVAC repairs. They can easily run a few thousand dollars, especially on bigger HVACs.
Notably, compressors often don’t fail all at once. As they weaken, your budget takes a second hit. With the compressor working harder, it also has to consume more electricity. In many units, the compressor can account for as much as 70% of the system’s electric consumption. Consequently, even a modest reduction in compressor performance can lead to higher energy bills, potentially to the tune of a 15% to 30% increase.
The extra strain extends to other parts of your HVAC. Evaporator and condenser coils may suffer extra stress because of inadequate pressurization. The refrigerant cycle can become overworked, leading to ice developing on coils. This ice triggers additional metal fatigue.
Overworking the HVAC also drives failures in the mechanical components, such as fans and blower motors. As these components run for longer cycles, bearings wear out. Seals and gaskets may also fail due to added operating stress. Motors can also overheat, too. Valves also suffer more wear with improper pressurization.
Worse, all of these failures lead to more refrigerant loss. A cascading series of failures causes to more inefficiency and wear. Ultimately, the negative feedback loop shortens your HVAC’s lifespan.
The Benefits of Regular Maintenance
The best way to avoid expensive repair bills is to schedule regular maintenance. Many homeowners schedule annual HVAC checkups with our company, and we even offer long-term maintenance plans. We strongly encourage an annual checkup for all units and a bi-annual checkup for systems over ten years old. A regular maintenance schedule usually extends a system’s expected lifespan by seven to 10 years.
A good preventative maintenance plan will address common failure points before they cause problems. Our technicians will verify that the system’s refrigerant is properly pressurized and charged. We also perform a visual inspection to look for signs like corrosion and oil spots. Scanning the system’s diagnostic computer may yield data about reported problems, cycle frequency, and average run times that indicate a potential refrigerant loss. We also run the system to identify problems. If AC repairs are necessary, we can perform them before your HVAC fails.
Scott-Lee Heating Company checks refrigerant losses on systems at places in St. Louis, MO and the surrounding areas, so schedule an appointment with one of our technicians today.