Why Your Thermostat Might Show a Temperature Split on Hot Days

At Bower Heating & Air Conditioning, we often get calls during Roanoke’s hottest days that sound something like:

“My thermostat is set to 72, but it’s 76 in here, what’s wrong?”

Good news: in many cases, nothing is broken. Your system is just working overtime against extreme outdoor heat and here’s why.

Understanding the "Temperature Split"

On especially hot days (think 90°F and above), your AC is doing its best to remove heat from your home and maintain your set temperature. But just like you, it gets a little overwhelmed under pressure.

A temperature split means the thermostat setting (say 72°F) and the actual room temperature (like 76°F) don’t match. This difference happens when the system:

• Can’t keep up with heat gain from sunlight and warm air
• Is fighting extra humidity (which makes it feel hotter)
• Has restricted airflow (like a dirty filter or blocked vent)
• Is designed for average temps, not extreme spikes

Think of It Like This:

Your AC is built to cool your home by about 20 degrees below the outdoor temperature. So on a 98°F day, your system may struggle to hold 72°F and holding 75°F may be its best output under that stress.

What You Can Do:

• Close blinds and curtains during the day
• Change your air filter regularly (every 30–60 days)
• Use ceiling fans to circulate cool air
• Don’t set the thermostat lower hoping it will cool faster, we promise, it won’t

If the temperature split is more than 5–6 degrees or lasts all day, it may be time for a tune-up.

We're Here to Help

If your system is falling further behind than normal or blowing warm air, it might need a quick checkup. Our team is ready to get you back on track.

Call Bower Heating & Air Conditioning today or send us a message online. We’ve got your comfort covered, even in a heatwave.