Every summer, without fail, we get some version of this question.

"Derek, my thermostat is set at 70 degrees, but my house is sitting at 74 degrees this afternoon. Is my air conditioner broken?"

The answer is maybe, but often the answer is no.

Sometimes your air conditioner is doing exactly what it was designed to do.

I think one of the biggest misconceptions homeowners have is believing every house should perform exactly the same.

That's simply not true.

Every Home Is Different

Two houses can sit side by side on the same street, be roughly the same size, have similar equipment, and perform completely differently on a 97 degree day.

Why?

Because every home has different demands.

Some homes are shaded by mature trees all afternoon. Others sit in direct sunlight from sunrise to sunset.

Some homes have upgraded windows while others still have original windows from decades ago.

Some homes have excellent attic insulation while others have very little protection from the heat sitting directly above the ceilings.

The direction your home faces matters.

The amount of shade matters.

The amount of glass in your home matters.

Even how often doors are opening and closing throughout the day matters.

​All of these things affect how hard your air conditioner has to work.

And Before Someone Says, "Well My Friend in Arizona Can Do It..."

I get it.

Every time we talk about this, someone says, "Well, my family in Arizona keeps their house at 70 degrees all day long."

That's great.

But Arizona isn't southeastern North Carolina.

Every climate is different.

Here in southeastern North Carolina, your air conditioner isn't simply fighting heat. It's fighting heat and humidity.

Humidity is the hidden workload most people never think about.

When it's 97 degrees outside and the humidity is high, your system is working overtime trying to make your house both cool and comfortable.

That's a lot different than a hot, dry climate.

Climate matters.

Location matters.

What works in Arizona, Nevada, Colorado, or other parts of the country does not always translate here.

Equipment Is Equipment

This is the part that sometimes surprises homeowners.

Your air conditioner is not designed to overcome unlimited heat.

When systems are installed, they are sized based on specific outdoor design temperatures. In our area, that's generally around 95 degrees.

When temperatures climb beyond that, the demands on your house increase dramatically.

If it's 97 degrees outside and you want 70 degrees inside, you're asking your system to overcome a 27 degree difference while also battling humidity.

That's a lot.

Can some homes do it? Absolutely.

Can every home do it? Absolutely not.

Again, every home is different.

People will sometimes say, "I spent a lot of money on this system. It should be able to do whatever I want."

I understand the thought process, but physics still wins.

Equipment is equipment.

No matter how efficient, expensive, or new a system is, every machine has operating limitations.

The Afternoon Is the Hardest Part of the Day

Many homeowners start to panic around 4 or 5 o'clock in the afternoon.

That's actually the most demanding time of the day for your home.

The roof has been baking in the sun all day.

The attic temperature has climbed.

The walls have absorbed heat for hours.

Windows have been allowing radiant heat inside.

At that point, your entire house has become one giant heat load.

Your air conditioner isn't just cooling air anymore. It's fighting everything the house has absorbed throughout the day while also removing moisture from the air.

Seeing your home rise a couple of degrees above your set point during those extreme conditions is not always a sign of failure.

The Real Test Happens After Dark

This is what I tell homeowners all the time.

Watch what happens after the sun goes down.

As outdoor temperatures begin to drop, your home should start shedding heat.

The roof cools down.

The walls cool down.

The heat load decreases.

Your system should begin catching back up.

If your thermostat is still climbing at 9 or 10 o'clock at night or your home simply refuses to cool down once outdoor temperatures have fallen, then we may have another issue.

That could be something such as:
-Low refrigerant
-Dirty indoor or outdoor coils
-Airflow restrictions
-Dirty filters
-Ductwork issues
-Aging equipment

Those are problems worth having checked.

Stop Playing Thermostat Games

One of the biggest mistakes homeowners make during extreme heat is constantly changing the thermostat.

They'll leave home and set it to 78 degrees.

Then they get home and immediately lower it to 68 degrees hoping it will cool faster.

That's not how air conditioning works.

Your system only knows one thing to do.

Run.

Setting it lower doesn't make it work harder. It simply makes it run longer.

During extreme temperatures, consistency is your friend.

Set it where you're comfortable and let the system maintain that temperature.

Here's the takeaway

Just because your house doesn't hit 70 degrees on a 97 degree afternoon does not automatically mean your air conditioner is broken.

Every home is different.

Shade matters.

Sun exposure matters.

Insulation matters.

Windows matter.

Humidity matters.

And where you live matters.

Here in southeastern North Carolina, your air conditioner is fighting two enemies every single summer day: heat and humidity.

At the end of the day, equipment is equipment.

The bigger question is not, "What is my house doing at 4 o'clock in the afternoon?"

The bigger question is, what is my house doing after dark?

If your system catches up once the sun goes down, it may simply be performing exactly as it was designed to do.

​If it doesn't, then it's probably time to have someone take a closer look before a small issue becomes a major repair.