Here’s what causes AC short cycling and how to fix it

“Short cycling” refers to an air conditioner that turns on, runs for only a short time, and then turns off again. This “cycle” then repeats, with the air conditioner constantly starting up. Most homeowners first notice this problem lying in bed at night, listening to the somewhat obnoxious sound of their air conditioner kicking on again and again. Of course, others notice discrepancies in their electric bill or problems with their home’s comfort. Both can be caused by AC short cycling.

If your air conditioner is short cycling, you need a professional HVAC technician to come out and take a look at it as soon as possible. As we’ll review below, short cycling can lead to a number of problems for air conditioners and heating systems, including compressor failure. Call us for professional cooling and heating service and inspections here in the Fresno metro area.

Noticing short cycling issues?

If your air conditioner or heater is short cycling, it’s time to bring in one of our HVAC experts for a closer look. At Allbritten, we help cool down Fresno homeowners with fast, friendly service and effective AC repair.


Why is AC short cycling so bad?

Just like your car uses the most gas when you turn the ignition, your air conditioner uses the most energy when first starting up the compressor. Under normal conditions, this extra energy use doesn’t amount to much. However, with a short cycling system, the compressor is constantly in the process of starting up, which means the AC unit is drawing more energy to produce less consistent cooling. There’s no two ways about it: short cycling, if left unchecked, will negatively impact your home’s cooling costs.

Unfortunately, that’s far from the only problem. All that starting and stopping puts additional stress on the AC compressor—a vital component that is incredibly expensive to replace. In fact, in most air conditioners more than a few years old, it makes more financial sense to replace the entire system than to replace just the compressor. Protecting the compressor from this unnecessary wear-and-tear should be your top priority, and it’s why you need to take on short cycling problems right away.

But, what causes short cycling in the first place? Here are a few common reasons why your air conditioner might be short cycling:

You have the wrong-sized air conditioner

There’s a common misconception out there that the bigger an air conditioner is, the better it is. After all, at face value, it makes sense, right? A larger air conditioner should be able to provide more cooling, more quickly. However, in the HVAC world, the unit size needs to be proportional to your home’s square footage. An air conditioner that’s too large for your house is going to have just as many problems as one that’s too small.

Some common causes of AC short cycling include refrigerant leaks and improper AC sizing.

One of the most common causes of long-term, persistent AC short cycling is improper AC sizing at the time of installation. This is why you should always have an experienced, locally trusted professional install your new AC unit.

Too large of an air conditioner will turn on and cool your home down. However, running at its normal speed, it’s unable to keep going without overshooting the temperature. So, it shuts itself off. The temperature in your home begins to rise again, and the thermostat turns the system back on. This repeats, over-and-over again, with the AC turning itself on and off in quick sequence. This is a classic example of AC short cycling, and it’s really bad for your comfort, your energy-efficiency, and your system’s compressor.

In contrast, an air conditioner that’s too small is also going to have issues. It’ll turn on, run, and struggle to keep up with the demand placed on it. It’ll constantly run, using more electricity without really cooling down your home. That constant, non-stop operation puts the system under incredible stress.

There’s a sweet spot between these two extremes. It’s why we offer free in-home estimates on new air conditioners here at Allbritten. Finding the right-sized air conditioner (or heater!) for your home matters, as it can prevent short cycling and a number of other critical, long-term problems.

How to fix this:

Unfortunately, if another AC contractor installed the wrong-sized air conditioner in your home, the solution might involve replacing it with a correctly sized system. Start by giving us a call so we can advise you on your next steps and consult you on what you can do to curb short-cycling with your current system.

Your AC unit is losing refrigerant

Refrigerant is what your air conditioner uses to cool down your home. Here’s a layman’s explanation: your air conditioner moves refrigerant in a closed loop that travels inside (evaporator coil) and outside (condenser coil). Inside, the refrigerant—supercooled by the compressor—absorbs heat energy from inside air. It then transports this heat energy to the condenser unit outside and releases it, cooling back down. The refrigerant makes this journey many, many times (known as the refrigeration cycle) until the temperature inside your home matches what the thermostat says.

The refrigeration cycle relies on pressure and sufficient refrigerant. Under normal conditions, your AC doesn’t need “new” refrigerant—it exists in a closed loop and doesn’t need to be replaced or topped off. However, in the event of a refrigerant leak, the air conditioner is going to struggle to operate normally. It will start to short cycle as it attempts to meet the temperature demand of your home.

How to fix this:

If you notice your AC is short cycling, please call our team so we can send one of our experienced, friendly techs out to your home. We’ll want to run through a full diagnosis of your air conditioner to determine what the problem is, and how we can best go about fixing it. In addition to refrigerant loss, short cycling can be potentially caused by a number of other malfunctions, including problems with the compressor, electrical supply, or the thermostat itself.

Here are the 3 biggest threats to your sewer line

Your home’s sewer line is arguably the most important part of your home’s pipes and plumbing. This line, typically PVC, copper, or—if your home was built prior to the 1960s—cast iron, is responsible for carrying all the wastewater out of your home to the municipal sewer. In other words, everything that goes down the shower drain, kitchen sink, or toilet travels through the sewer line. There are several threats to your sewer line you need to watch out for, however.

Common sewer line problems include clogs, leaks, and pipe movement. These issues can cause homeowners a whole lot of headache. Sewer line clogs, for instance, can lead to a sewer backup: a disastrous event in which wastewater comes back up through the drains into the home.

It’s critical that homeowners take sewer line threats seriously. In this article, we’ll review the major threats to your sewer line and what you can do to prevent them or—if it’s already too late—address them with our professional drain cleaning services.

Think you might have a clogged sewer line?

Contact our plumbers right now to schedule an inspection.


Thirsty tree roots

The buried sewer line most likely runs from the home’s foundation through your front or side yard to the street, where it connects to the municipal sewer. The trouble typically starts with a small leak in the line: a hairline fracture or separation that allows moisture to escape. This attracts any nearby tree roots, thirsting for a drink and nutrients. Some species have aggressive, fast-growing root structures that hone in on the sewer line like a heat-seeking (or, in this case, water-seeking!) missile.

Once the root reaches the sewer line, it often starts to grow around it and—in search of even more moisture and nutrients—into it. Tree roots are powerful enough to break open cracks in PVC or copper pipes. Not only will this exacerbate the leak, but it could be the start of a partial or complete clog in the line. Once the tree root completely takes up the circumference of the line, your home is at imminent risk of a sewer line backup.

Preventing tree root issues

To prevent this nightmare from happening, it’s best to take several precautions on behalf of your sewer line. First, take note of where your line is buried underground, and any trees, bushes, or shrubs within a 10-15 foot perimeter of the line. If there are trees overhead, do some research into the species, and consider calling an arborist.

Some trees and bushes with slow-growing, less-aggressive root structures may pose minimal threat to the line, while others—such as the California Pepper Tree—may need to be proactively relocated to another part of your property.

Dealing with tree root issues

If you have a root structure already growing around or into the line—which you’ll notice if you have a partial clog in your home’s sinks, showers, and toilets—it’s time to call out a professional plumber. At Allbritten, our plumbing team has the tools to safely clear sewer line clogs and make an effective sewer line repair. Of course, once this is done, you’ll want to revisit the idea of moving the offending tree somewhere else in your yard.

Shifting soil

Your sewer line doesn’t feature any kind of pump: the entire system uses gravity to move wastewater away from your home to the municipal sewer. To take advantage of this natural force, the entire line is slightly sloped, so that the end connected to your home is higher in elevation than the end by the street. This slope is very gradual: plumbing installers recommend a minimum slope of a 1-inch drop for every 8 feet of line. Depending on how far it is to the sewer, the entire sewer line might only be sloped by a few inches.

Common threats to your sewer line include shifting soil and thirsty tree roots.

A PVC sewer line, like this one, is potentially vulnerable to thirsty tree roots.

It’s worth noting that this slope is a “Goldilocks” situation where precision is key. Too little slope, and the sewer line won’t drain properly. Too much slope, and you have a different problem: liquids will drain too quickly, leading to clogs.

However stable it feels under our feet, the ground is constantly moving. Over time, soil subsides and expands under different conditions. This shifting and movement can lead to several problems for your sewer line. Most commonly, parts of the line will sag, creating a gentle “valley” in the line. This puts pressure on the line and can cause it to crack, but it also means the line is no longer draining properly. Soil movement can also “lift up” the sewer end of the line, taking its slope angle out of that aforementioned “Goldilocks” zone.

Preventing soil issues

Here in California, a lot of soil subsidence occurs when parched earth is then flooded with rainwater. This issue is often exacerbated by our gutters, which carry rainfall off of the roof and dump it right onto the ground surrounding our home. One thing to consider installing are gutter or downspout extenders that will carry this moisture away from the yard, or at least distribute it more evenly. Some homeowners have even set up gutters that take rainwater to their gardening beds!

Dealing with soil issues

Any issues with soil movement and your sewer line require the help of an experienced plumber. We’ll need to inspect the problem and advise you on your next steps. This may include digging up the line so that it can be fixed and reoriented to the correct slope.


Yes, you read that right. Homeowners are perhaps the most pressing threat to their home’s sewer line. That’s because many sewer line clogs start in the kitchen. Certain types of food and cooking waste, when put down the drain, can start to form a nasty clog, deep in the line. Once this clog completely obstructs the line, you’re in trouble.

Preventing sewer line clogs

To avoid sewer line clogs caused by kitchen food waste, you need to start thinking twice before running your in-sink disposal. In general, avoid putting these major clog-causers down the drain:

  • Cooking grease and oils: As these cool on their way through the sewer line, they start to solidify and stick to the interior walls of the line.
  • Uncooked rice and pasta: These foods expand as they absorb moisture. A handful of dry rice accidentally put down the drain can start to expand into a clog-forming mess.
  • Flour: As any home baker knows, flour and moisture is the starting point for a sticky, glue-y dough. The same thing happens in your sewer line.
  • Coffee grounds: Coffee grounds tend to clump together, allowing them to form a water-blocking clog in the line.

As a general rule of thumb, never dispose of these food and cooking byproducts down the kitchen sink. Instead, throw them in the garbage. For hot grease and oil, take a leftover glass jar—upcycled sauce or salsa jars work great for this—and allow the grease to cool and solidify in the glass before chucking it into the trash.

Dealing with sewer line clogs

Your first warning sign of an impending sewer line disaster is all of your home’s drains clogging simultaneously. This means the problem isn’t with a single drain—it’s with the one drain connected to all of them. Immediately turn off the water supply for your home and call us for fast service here in Fresno.

Our team has professional-grade drain cleaning and sewer line unclogging equipment that allows us to reach deep into the line and unclog it.

Guard against threats to your sewer line

Given the critical role it plays in your home and the dire consequences of any problems, it’s worth it to think ahead about the key threats to your sewer line and take steps to prevent or address them. If you need more information, or want a professional to come out for a consultation, please don’t hesitate to contact our team.

As Fresno’s leading plumbing repair company, our team is ready to help you tackle any project or problem in your home.