My AC Can’t Keep Up! House Not Cooling

Name: Magic Touch Mechanical
Price range: $$

August 16, 2020

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 and see on our contact us forms every summer when the extreme heat arrives in Phoenix, AZ.

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.

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 (update) this article in August, temperatures are 115°+ degrees in Mesa, AZ. I only turn my temperature up two degrees when I leave the house for work. 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.

Note: This advice does not apply to people who are attempting to “pre-cool” their homes during certain hours. If you’ve been advised to pre-cool, and your home is a good candidate, stick with the plan!

COVID-19 Update : Since I originally wrote this article, many more people are working from home. Many families also have kids home from school. If you’re only now noticing your A/C doesn’t keep up in the heat of the day, it may not be a new problem. Start observing which rooms are hottest, what time of day is it the worse, etc. Doing this will give you and your HVAC professional clues about what’s likely the problem, or problems plural.

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 solar shade screens for the summer which will allow you to keep your blinds or curtains open while blocking as much as 90% of the solar gain, so you don’t have to feel like you’re in a cave. 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 has become somewhat of an inside joke, in the HVAC industry, because we hear it constantly although it’s not as common a problem as people think it is. Newer equipment does not run on Freon (R-22 Refrigerant), most run on R-410a nowadays. While refrigerant never wears out or evaporates, a refrigerant leak can cause an AC unit to be unable to keep up and will eventually stop working all together.
Overheating Fan Motor or Compressor

A failing fan motor or compressor can sometimes overheat and stop working, then after cooling down, start operating normally for a while until it overheats again. When this happens, it can be tricky to catch because the problem is intermittent. The temperature in the home will creep up every time the motor shuts-off but then 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 reducing the temperature. The outdoor unit known as the condenser is where this magic takes place. If the outdoor condenser coils are clogged with dirt and debris the unit cannot expel the heat it needs 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 problems and faulty metering devices like TXV’s can have similar symptoms so an experienced HVAC technician knows to look further before blaming the TXV. That said however, a faulty metering device can cause the unit to not run properly and therefore can lead to an AC unit that just can’t keep up with the summer heat.

It’s probably best to call on a qualified, licensed air conditioning repair company if you suspect your AC unit has any one of the above problems. Do you live in Mesa, Phoenix, Chandler, Peoria, or other nearby AZ cities? If so, just call Magic Touch or fill out a Contact Us Form on our website. 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. When you consider that your attic is about 30-40 degrees hotter than the outside air, 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.
Radiant Barrier

Phoenix and radiant barrier are a match made in heaven. Radiant barrier is a reflective foil, or spray-on paint-like material. It is adhered to the underside of the roof in your attic. Where as insulation decreases the thermal heat that has already entered the attic from moving into the air conditioned space, radiant barrier deflects the heat before it has a chance to enter the attic. Our technician training room at the Magic Touch Mechanical office in Mesa, AZ has radiant barrier installed under the roof-deck. The resulting decrease in heat gain we measured the day after installation was incredible!
Attic Fans (Solar or Electric) – Don’t do it!

There are a lot of 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 energy audits we perform 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 through air leaks, literally making 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, and I stress if: Your ducts have been tested and sealed, your home and attic (infiltration and exfiltration) have been tested and sealed for air leaks, and a few other tests have been conducted. It’s important to stress approximately 85% of the homes we have tested with attic fans show 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. Keep in mind we’re not talking about heat getting in through poorly sealed windows (that’s infiltration). We’re talking about the heat coming through the glass itself, and yes, 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 and can say undoubtedly the difference was immediately noticeable from regular bug screens. 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 even find major duct leakage in very high-end, relatively new homes. The reason this can prevent your AC from not keeping up with the summer heat is obvious, right? If not, use the search tool on our blog page and search for terms like; duct leaks, duct leakage, and energy audit, and you will find articles dating back years that talk about why sealing leaky air ducts is so important.

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. If not you can call us if you are in our service area…we have the tools, certifications, knowledge, and experience to not only make you comfortable again, but to save you significant money on your power bills!

You may have noticed I never once mentioned weather-stripping doors and windows – the go to solution of those who haven’t been studying and practicing building science and home performance for decades. Sure you want to make sure your doors and windows are sealed as tight as possible – but on the list of things that cause uncomfortable homes, and air conditioners that can’t keep up in Phoenix, I can assure you it’s at the very bottom of the list.

Need Help Finding Why Your Home AC Can’t Keep Up?

If you live in our service area, give Magic Touch Mechanical a call, or send us a message. Let us show you why we’ve been awarded as one of the best HVAC Contractors in the country!