If you’ve been thinking my AC can’t keep up, isn’t keeping my house cool, or noticed that lately your AC runs constantly: This article will give you a good idea of what’s going on & what to do about it.
- “My AC wont cool below 80 degrees” (or 84, 85, etc.).
- “My air conditioner doesn’t keep up with the heat in the summer.”
- “I think my ac needs Freon, it’s not keeping up.”
- “My AC takes hours to cool the house down a few degrees.”
These are all things our Customer Service Rep’s at Magic Touch Mechanical hear over the phone every summer. When extreme heat arrives in Phoenix, AZ., many Chandler, Gilbert, Scottsdale, and Mesa struggle to keep homeowners comfortable. There are many reasons a central air conditioner might not keep up with the heat in the summer in Arizona. After all, Phoenix and nearby cities reach some of the highest summer temperatures in the country.
There may be a problem with your AC that requires diagnosis and repair from a licensed HVAC Contractor. However, it may surprise you to learn that the problem may, or may not be your air conditioner’s fault. Here’s some reasons why your AC unit just isn’t keeping up with the summer heat.
If you’re in the Phoenix east valley or west valley and need AC help fast, schedule online right now by clicking the button below!
Problems YOU May be Creating That Prevent the AC From Keeping Up with the Phoenix Heat
- Thermostat Settings On a warm summer day – say 85-98 degrees, we recommend you turn your thermostat up when you leave for work. However, no higher than 84 degrees. This is a good way to save energy over the course of time. This way, the AC doesn’t have to work too hard to bring the temperature down to somewhere between 75-80 degrees. On hotter days (98 degrees & above), we recommend you let that unit run so it can “keep up.”
As I write this article in July 2025, temperatures are forecasted to hit 115°+ degrees in Mesa, AZ this week. You will not save money on these really hot days by turning your AC up when you leave for work. In fact, it will most likely cost you more money because the unit will work much harder. All the components will run much hotter trying to “catch-up” vs. “keep up”. Not to mention you’ll be miserable most of the evening until the whole house cools back down.
Pro Tip: This advice does not apply to people who “pre-cool” their homes. If you’ve been advised to pre-cool, and your home is a good candidate*, stick with the plan! *Pre cooling is not always advised. Read: AC Supercooling: How To Supercool & Should You for more information.
- The Greenhouse Effect Solar heat gain through windows, especially South and West facing windows play a huge role in where heat gets into your home in the first place. We all want our home to feel bright and inviting, but there’s a cost – both financially and to your comfort. We recommend installing solar shade screens in the summer. They allow you to keep your blinds or curtains open while blocking as much as 90% of the solar gain. This way, you don’t have to feel like you’re in a cave, but are also reducing heat gain.
Pro Tip: If you’re going to be gone for the day, close your blinds (with the blades facing up) as well.
Problems With Your A/C Unit That Prevent it From Keeping Up
- Refrigerant Leak The ever constant “I think my unit needs a Freon charge” call is an inside joke in the HVAC industry. We hear it constantly although it’s not as common a problem as people think. While refrigerant never wears out or evaporates, a refrigerant leak can cause an AC unit to be unable to keep up. And, eventually stop working all together.
- Overheating Fan Motor or Compressor A failing fan motor or compressor can sometimes overheat and stop working. After cooling off, it may start operating normally for a while … until it overheats again. It can be tricky to catch in the act because the problem is intermittent. The temperature in the home will creep up every time the motor shuts-off and start producing cold air again when it turns back on.
- Dirty Condenser Coils An air conditioner doesn’t actually make cold air, it removes heat from the air thereby reducing the temperature. The outdoor unit known as the condenser is where this magic takes place. If the condenser coils are clogged, the unit cannot expel the heat needed to cool your home down.
- Dirty Evaporator Coils Evaporator coils, also known as the indoor coil need to be clean in order for air to pass across the coils freely. When these coils become plugged up with dirt, they begin to freeze up making matters worse. When you stick your hand up to a register (air vent) and feel no air movement, this is often the culprit.
- Faulty Metering Device Another inside joke in the HVAC industry is “It’s got a bad TXV”. This time though the joke is on rookie HVAC Service technicians that jump to a conclusion before finalizing their diagnosis. Refrigerant charge issues, contaminants in the system, and problems from faulty metering devices like TXV’s have similar symptoms. An experienced HVAC technician knows to look further before blaming the TXV. That said, a faulty metering device can cause the unit to not run properly and therefore can lead to an AC unit that can’t keep up.
It’s best to call on a qualified, licensed air conditioning repair company if you suspect your AC unit has a problem. Do you live in Mesa, Phoenix, Chandler, Peoria, or other nearby AZ cities? If so, just call Magic Touch. We’ll see to it that you’re happy you did!
Problems With Your HOME Can Prevent Your AC From Cooling Down
- Inadequate Attic Insulation Heat moves from hot to cold. The greater the temperature difference the faster it moves. Your attic is about 30-40 degrees hotter than the outside air. Example: On a 110-degree summer day in Phoenix, your attic is somewhere between 140 to 150 degrees.
Without a good “thermal boundary” between your attic and the conditioned part of your home, that heat will find its way into your air-conditioned home. The higher the “R-Value” (Resistance Value) of your attic insulation, the higher the resistance against heat penetrating it. - Attic Fans (Solar or Electric) – DON’T DO IT! There are a few shady (or perhaps just ignorant) air conditioning companies in Phoenix that install attic fans. Unfortunately, they’re misinforming people by telling them a cooler attic will mean a cooler home. Or will save them lots of money in lower utility bills.
In the majority of home energy audits we’ve performed over the years we find the exact opposite is true.
More often than not we find attic fans are actually pulling cold conditioned air out of the home. This actually makes the house warmer while you pay for that fan to cool your attic with air your AC just cooled. In addition, attic fans are sucking cold air right out of your leaky ductwork!
Attic fans can be a good thing if: Your ducts have been tested and sealed, your home and attic (infiltration and exfiltration) have been tested and sealed.
Pro Tip: In 85% of the homes we have tested with attic fans, the fan is having a negative impact on efficiency and comfort. - High Solar Heat Gain As discussed above, one of the fastest ways heat enters a home is through sun-struck windows.
I’m don’t mean heat getting in through poorly sealed windows (that’s infiltration). I’m talking about the heat coming through the glass itself. While better windows will slow down that heat transfer, the key is to stop it before it hits the window. I have 80% UV blockage solar shade screens on every window in my home. These screens are mounted outside over the glass so the solar heat never gets to the glass in the first place. - Air Duct Leaks Leaky ducts are more common than not in Phoenix. We find major duct leakage even in very high-end, relatively new homes. The reason this can prevent your AC from not keeping up is probably obvious to anyone reading.
Obviously, there are other reasons why a central air conditioner can’t keep up with the summer heat in a hot place like Phoenix, Arizona.
Many times, it’s a number of these things that all add up to uncomfortable homes and high summer bills. The good news is you now know a few things you can do that may help solve the problem. You can call us if you want a pro to fix it for you! We have the tools, certifications, knowledge, and experience to make you comfortable again. Not only that, we’ll help you save significant money by knocking down your power bills!
What About Weather Stripping?
You may have noticed I haven’t mentioned weather-stripping doors and windows. You absolutely want to make sure your doors and windows are sealed as tight as possible! However, on the list of reasons your AC can’t keep up in Phoenix, I can assure you leaky door seals are rarely the main culprit. Again, don’t neglect weather stripping repair when needed. However it’s typically a minor source of heat gain compared to other common issues we’ve discussed in this article.
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