Why Is My HVAC Not Reaching the Set Temperature?

When your HVAC system isn't reaching the temperature you've set on your thermostat, it's more than just annoying—it can disrupt your comfort, sleep, and energy efficiency. Whether your thermostat is set to cool but the AC is not turning on, or your thermostat reads 80 when it's set at 72, this issue is often a sign that something in your HVAC system or thermostat isn't working as it should.

For homeowners in Metro Atlanta, where summers are hot and winters can get chilly, this is a problem that needs a fix—fast. In this article, we'll break down what's happening, why it matters, and what you can do about it. We'll also cover common issues like "thermostat won't turn on" and "AC running constantly but not cooling." Let's dive in.

Why Is My HVAC Not Reaching the Set Temperature?

If you've ever walked into your home and realized it feels warmer (or colder) than it should, even though your thermostat is set correctly, you're not alone. This issue usually stems from one of three things: a thermostat problem, an HVAC system malfunction, or extreme outdoor temperatures pushing your system past its limits.

Here's why this issue is worth paying attention to:

• It leads to discomfort in your home
  
  

• It can drive up your energy bills
  
  

• It could be an early warning sign that your system is failing
  
  

Let's look at the most common reasons your HVAC might not be reaching the set temperature—and what you can do about it.

1. The Thermostat Might Be the Problem

Your thermostat is the brain of your HVAC system. If it's not reading the temperature correctly, your system won't respond properly.

Common thermostat issues include:

Thermostat set to cool but AC not turning on

First, make sure it's actually on and set to the correct mode (cooling or heating). A power issue or a tripped breaker could be stopping it from sending signals to your HVAC system.

Thermostat set at 72 but reads 80

This usually means the thermostat is either faulty or located in a spot that gives inaccurate readings—like next to a window or in direct sunlight.

Thermostat won't turn on

Check the batteries (if it uses them), and make sure it's wired correctly. If it's a new install, improper wiring is a common culprit.

Air conditioner thermostat not working at all

This could indicate an internal failure or that it needs to be cleaned or recalibrated.

Quick Fixes:

• Reboot your thermostat (turn it off, wait 10 seconds, and turn it back on)
  

• Replace the batteries
  

• Clean it gently with a soft brush

• Check for tripped breakers or blown fuses

If none of that works, it may be time to replace your thermostat or call a technician.

2. The HVAC System Is Working Overtime (But Getting Nowhere)

Even with a perfectly functioning thermostat, your HVAC might still not be hitting your set temperature. If your AC is running constantly and does not shut off when the set temp is reached, or your system isn't cooling like it used to, here are a few likely reasons:

Dirty Air Filters

This is one of the easiest problems to fix. A clogged air filter restricts airflow and makes it harder for your system to cool or heat your home.

Fix:
Replace the air filter every 1-3 months, especially during peak seasons in Metro Atlanta.

Blocked Vents or Dirty Ducts

Blocked or dirty vents can reduce airflow, while leaky or dirty ductwork can let conditioned air escape before it reaches your rooms.

Fix:
Make sure vents are open and unblocked. A professional duct cleaning can help restore proper airflow.

Undersized or Oversized System

If your HVAC system isn't properly sized for your home, it won't perform efficiently. An undersized system can't keep up; an oversized one short cycles and doesn't run long enough to properly condition the air.

Fix:
Have a professional assess your system's size and performance.

3. Outdoor Conditions Are Working Against You

Here in Metro Atlanta, the summer heat can push your AC to its limit. If your thermostat is set to 72 but it's 98 degrees outside with high humidity, your AC might not be able to keep up—even if everything is working properly.

Real-life example:
You come home from work, and your house feels like an oven. Your thermostat is set to 72, but it reads 80. You think your AC is broken—but it's really just battling against extreme heat and poor insulation.

Fixes to help your system out:

• Use blackout curtains or blinds during the hottest part of the day
  
  

• Seal doors and windows to prevent cool air from escaping
  
  

• Use ceiling fans to circulate air more efficiently
  

4. The Location of the Thermostat Matters

If your thermostat is installed in a poor location, it can cause misleading temperature readings. Common bad locations include:

• Near windows
  
  

• Next to the kitchen or oven
  
  

• In hallways that don't reflect the actual living space temperature
  

Fix:
Relocate the thermostat to a central, shaded area away from heat sources. This is a job best left to HVAC professionals.

5. Your Thermostat Needs a Reset—or Retirement

If your thermostat has been in use for a while, or if it's been acting up, it might need a reset or replacement. Over time, electronic components wear out or become less reliable.

Signs it's time for a new thermostat:

• Frozen or unresponsive screen
  
  

• Erratic behavior or frequent resets
  
  

• Difficulty maintaining temperature
  
  

• Thermostat age (older than 10 years)
  

Fix:
If a quick reboot doesn't fix it, upgrading to a smart thermostat can be a great option. Smart thermostats offer better accuracy, learning capabilities, and can help you save on energy costs.

Common Scenarios and What They Mean

Conclusion: Why Is My HVAC Not Reaching the Set Temperature?

If your HVAC system isn't reaching the temperature you've set, the problem could lie with the thermostat, your HVAC system's condition, or even extreme weather conditions. It's a frustrating issue—but often a fixable one.

Before calling for help, check:

• Is your thermostat working and properly placed?
  
  

• Are your filters and vents clean?
  
  

• Is your HVAC system the right size and in good shape?
  

Still stuck? That's where Bardi comes in.

Our Metro Atlanta team specializes in HVAC repairs, system diagnostics, and thermostat troubleshooting. We'll get to the root of the problem quickly—so your home gets back to feeling just right.

Call Bardi today or schedule an appointment online. We'll help you get comfortable again.