Watkins Heating & Cooling Blog The Cause of Freon Leaks What causes a/c evaporator coils to leak? We have found this to be the most common problem plaguing air conditioners. To explain this, we first need to bust a common air conditioner myth. A Common A/C Myth Many homeowners believe that, over time, an air conditioner uses freon. Maybe a long, hot summer leaves a perfectly good air conditioner "winded" and low on freon. We just need to tune-up the a/c and top-up the freon, right? In reality, an air conditioner or heat pump has a sealed refrigerant system that should never "use up" or run out of freon. The freon or refrigerant is only the medium used to transfer heat from the inside of the home to the outside. The only resource that is expended is electricity. If the freon is not consumed in the process of cooling your home, then it must be lost only by a leak in the copper tubing. For many years, the air conditioning industry has used copper tubing to harness the pressure of refrigerant and bring comfort to the masses.

Copper is soft and abundant, and easy to seal in the field with solder or brazing alloy. If copper is such a good material, why do we see so many freon leaks? Is this due to poor field connections, poor manufacturing, or is there a third possibility? Trane Looks for the Root Cause A number of years ago, Trane began a study to determine the true cause of this constant threat to our comfort. As service technicians, we have noticed that leaks from field or factory connections cause problems in the first year and are fairly rare. The problem leaks that develop in a 4 - 7 year old air conditioner occur in the copper tubing wall not the connection points or braze joints. The source of these pre-teen leaks is what the Trane engineers set out to find in their study. Our technicians have noticed that certain brands of air conditioners develop leaks faster than others and that the newer, more efficient air conditioners are more prone to leaking than the old energy hogs. The reason for this seems fairly obvious to HVAC contractors.

A/C manufacturers can raise the efficiency of their equipment by using thinner copper in their evaporator coils. Heat transfers faster through the thinner copper, but this efficient tubing also leaks sooner. One could argue that the legislation that raised the minimum efficiency of air conditioners and heat pumps to 13 SEER resulted in thinner tubing walls, more evaporator coils leaks, and, as a result, more ozone-damaging freon released into the atmosphere. The Real Cause of Freon Leaks So we know that thinner tubing develops leaks sooner, but what is causing the freon leak in the first place? The leaky a/c coils that the Trane engineers studied had microscopic pin holes seemingly drilled throughout the coil tubing. Trane's in-home studies revealed that the culprit was formic acid. Formic acid was corroding the copper and drilling these tiny pin holes. The acid penetrates the thinner, high-efficiency tubing faster and is making some air conditioner brands look very bad. But where is the formic acid coming from?

Isn't that what gives fire ants their sting? What is formic acid doing in our homes and on our air conditioner coils? Is Formaldehyde the Culprit? Formaldehyde in the home can convert into Formic acid on the a/c coil. It is extremely mild, but over a period of 5 years, it will produce pinholes in copper tubing. We call this process formicary corrosion, and it is the main reason that we still buy R-22 by the skid. If you have researched indoor air quality, you'll know that formaldehyde is a major pollutant in our homes. air handling unit informationAn infamous case of severe formaldehyde in the living space was the FEMA trailer provided to Katrina victims. outside ac unit coverWhile less severe than a FEMA trailer, most homes have a measurable amount of formaldehyde in the indoor air, and this will always cause formicary corrosion and freon leaks.cost of external ac unit

The Cure for A/C Freon Leaks Stop using copper to manufacture cooling coils. The photos above show copper and aluminum coil tube walls subjected to a formic acid corrosion test. Trane has found that aluminum is not susceptible to formicary corrosion. Through great feats of science and manufacturing genius, Trane began production of an all-aluminum air conditioning coil in 2005. Since then, we have installed many Trane all-aluminum coils, and we have yet to see a single leak in the tubing walls. This truly is an amazing track record. We believe this makes Trane the only reasonable choice for your next air conditioner. Comparison of Trane coil and typical copper coil after a 500 hour salt spray test.Troubleshooting 8 Common Air Conditioner Problems Poor maintenance can result in an air conditioner that performs poorly Of course it’s on the hottest days that you notice your air conditioner is struggling. And it’s not always the fault of the equipment. A poorly maintained system can perform poorly, failing to keep you cool while costing you more to run.

Here are some reasons why your air conditioner isn’t working as well as it used to. Your filter is dirty. If you haven’t cleaned the filter in your room air conditioner recently, do it now. Filters on central AC units should be changed at least once a month, especially if your system is running constantly or you have pets.If so, reseal around your unit with pieces of weatherstripping. TV is too close to the AC. Avoid placing lamps or TV sets near the thermostat that controls your central air or near your window unit. Registers are dirty or blocked. If you have a forced air heating and cooling system, regularly vacuum the registers to remove any dust buildup. Make sure that furniture and other objects are not blocking the airflow through your registers. Thermostat is on the wrong setting. If you have a programmable thermostat, make sure you programmed it so your home is at a comfortable temperature when you’re there and a bit higher when you’re not. And keep in mind that for every degree you raise the temperature, you’ll save 3 percent on your air conditioning costs.

Window units, of course, don’t offer the whole-house control of a central system. If you’re depending on one window unit to cool a large space you’ll have to experiment with the thermostat setting as the temperature will vary depending on where you are in the room. It’s too sunny inside. If your room AC unit is in a sunny window, it’ll have to work harder to cool your space. Likewise, if the thermostat for your central system is in a sunny spot, it will register the wrong temperature. Your best bet is to keep your shades and curtains drawn all day during the heat of the summer. Plants are crowding the compressor. The outdoor compressor for central air needs adequate airflow to work correctly, so make sure there’s at least 2 to 3 feet of space between the unit and any plants or structures. There should also be 5 feet of clearance between the top of the unit and any trees above. You forgot an annual checkup. An inspection by an HVAC technician can catch any serious problems before they get worse and leave you hot and bothered at the peak of summer.