Many homeowners assume that dropping the thermostat far below their desired temperature will make their home cool down faster. In reality, this common habit doesn’t speed up the cooling process at all. It simply forces your air conditioning system to run longer, work harder, and in some cases—even freeze up. At Comfort Heating & Cooling, we often help St. Joseph homeowners troubleshoot issues that stem from this exact misconception.

The truth is simple: your AC can only cool at one speed, no matter how low you set the thermostat. Understanding how this works can help you stay comfortable, protect your system, and avoid unnecessary repair bills.

How Your Air Conditioner Actually Cools Your Home

Your air conditioner isn’t like the gas pedal in a car—you can’t make it work faster by “pushing” it harder. Whether you set your thermostat to 72° or 55°, the system cools your home at the same steady rate. The thermostat is just a control switch. When it senses that the indoor temperature is above the target, it tells the AC to run. When the target temperature is reached, the system shuts off.

So if you set the thermostat extremely low, the AC will simply run nonstop trying to reach a temperature it may never be able to achieve—especially during hot Missouri summers.

Why Lowering the Thermostat Doesn’t Speed Up Cooling

Most air conditioning systems in St. Joseph homes remove heat at a fixed rate. They are designed to drop the indoor temperature by a certain number of degrees per hour under normal conditions. Lowering the thermostat beyond your actual comfort level won’t increase that cooling capacity. It only stretches out the run time.

For example, if your home is 80° and you want it at 72°, setting the thermostat to 60° won’t make it reach 72° any faster. The system will cool at the same speed—but now it will keep running long after reaching 72° because it’s trying to reach a much lower temperature.

When the AC Runs Nonstop, Problems Follow

Here in St. Joseph, we see it all the time—especially during heat waves. If the thermostat is set too low, the AC may never cycle off. Extended nonstop operation leads to:

• Higher energy bills
• Excessive wear on parts
• Shortened lifespan of the system
• Reduced indoor comfort from humidity build-up

For a family-owned HVAC contractor like Comfort Heating & Cooling, helping customers avoid unnecessary breakdowns is part of what we do every day. A simple thermostat adjustment can prevent hours of wasted energy and system strain.

A Dirty Air Filter Makes Everything Worse

If your AC is running nonstop and the air filter hasn’t been changed recently, you may be setting the stage for even bigger issues. A clogged filter restricts airflow. Without proper airflow, the evaporator coil can get too cold—much colder than it should—and begin to freeze.

Yes, your air conditioner can literally ice up in July. We see it frequently during emergency AC repair calls throughout St. Joseph, Missouri. The combination of an overworked system AND a dirty filter is one of the most common causes.

When the coil freezes, cooling stops completely. You may notice:

• Warm air coming from vents
• Ice on the refrigerant lines or outdoor unit
• Water leaking once the ice melts
• A strong musty smell

This usually requires shutting the system off for several hours and then having a technician inspect it. Thankfully, it’s highly preventable—just change your filter regularly and avoid drastic thermostat settings.

How to Use Your Thermostat the Right Way

Smart thermostat use can help you stay comfortable, protect your system, and save on energy bills. Comfort Heating & Cooling provides smart thermostat installation throughout St. Joseph, MO, and we always recommend the following tips:

• Set your desired temperature and leave it—don’t “push” the system
• Adjust gradually (1–2 degrees at a time)
• Use programmable schedules to avoid unnecessary cooling while you’re away
• Never set the thermostat below 68° during cooling season
• Change your air filter every 30–60 days during heavy use

These simple habits keep your AC efficient, reduce the risk of freezing, and help avoid costly breakdowns.

Why Your System Might Not Hit Extremely Low Temperatures

During peak summer heat in northwest Missouri, even the best systems have limitations. Most air conditioners are designed to cool a home about 20 degrees below outdoor temperatures. If it’s 100° outside, expecting your AC to maintain 65° indoors isn’t realistic—even with a top-rated system from a trusted HVAC repair company in St. Joseph. In these cases, running the AC nonstop won’t cool your home further; it only increases energy use and strain.

What To Do If Your AC Keeps Freezing or Running Constantly

If you're already experiencing nonstop running or icing issues, it may be time to call a residential HVAC contractor. Comfort Heating & Cooling provides emergency AC repair in St. Joseph and can quickly diagnose whether the issue is related to airflow, refrigerant, thermostat problems, or system sizing.

Sometimes the fix is simple—like changing a filter or recalibrating a thermostat. Other times the issue indicates a deeper problem that requires professional attention. Either way, addressing it early helps protect your comfort and your system’s long-term performance.

FAQ

Does lowering the thermostat make the AC cool faster?

No. Your air conditioner cools at a fixed rate. Setting the thermostat lower only makes the system run longer.

Can an AC freeze up in the summer?

Absolutely. Restricted airflow—often caused by dirty filters—can make coils drop below freezing, even on the hottest days.

What temperature should I set my thermostat in the summer?

Most systems operate efficiently around 72–76°. Going below 68° increases strain and energy usage without improving comfort.

Why does my AC run nonstop when it’s very hot outside?

Your system may be trying to reach a temperature it can’t achieve. Air conditioners are typically designed for a 20-degree temperature difference from outdoors.

When should I call for professional help?

If the system is freezing, blowing warm air, or never shutting off despite reasonable thermostat settings, it’s time to call an HVAC expert in St. Joseph, MO.

For reliable AC repairs, smart thermostat installation, or seasonal HVAC maintenance plans in St. Joseph, Comfort Heating & Cooling is here to help—because when comfort matters, our family-owned team is always ready to serve.