The Real Reason Your House Has Hot and Cold Spots

Walking through your home, you notice your hallway is much hotter than the bedroom. Even after you adjust the thermostat, the hallway feels warmer and more humid than the rest of the house. Why does this happen?

Uneven temperatures can be frustrating and can lead you to feel uncomfortable in some areas, but they can also signal that there are issues with your HVAC system. Identifying what’s causing hot and cold spots will allow you to take steps to solve the problem.

Key Takeaways

• Uneven temperatures inside the home are often caused by airflow issues, ductwork leaks, or poor insulation.
• Environmental factors, such as the direction a room faces, influences temperatures.
• Some simple issues include unblocking vents or sealing gaps or cracks around windows or doors.

Common Reasons for Hot or Cold Spots

Understanding the root causes of temperature issues can help you identify the problem behind hot or cold spots in your home:

Poor Airflow from Vents

Your HVAC moves air through your home. Your home’s layout, furniture, rugs, and curtains can affect airflow. And in some cases, poor airflow is due to clogged filters, forcing the blower motor to have to work harder to move the air. Together, these factors can damage your HVAC’s efficiency, leading to some spots feeling hotter or colder.

Leaky or Poorly Designed Ductwork

Ducts are necessary for moving air-conditioned air through your home. But 20% to 30% of air that moves through the duct system is lost due to leaks, holes, or weak connections, according to Energy Star. An aging ductwork system can reduce your home’s airflow.

“A lot of the real problems come from ductwork,” said Joey Dooley, general manager with ARS in Texas. “If the ducts are installed improperly, if there are restrictions, if things are sealed badly, then you’re not getting the efficiency you paid for. For example, we can change to higher-efficiency equipment, but if the airflow and duct system aren’t right, you’re not going to get that full efficiency.”

Inadequate Insulation

Your home’s insulation acts like a blanket, helping to trap in the cool air in the summer, and the warm air in the winter. If your home has thin walls, poor insulation, or single-pane windows, air escapes, and outdoor temperatures can creep in, causing hot or cold spots.

Sun Location

The sun causes a significant amount of radiant heat. Rooms that get a lot of natural light during the day absorb this heat throughout the afternoon. Even if your AC is running, your system may struggle to counteract the natural radiant heat pressing in from outside.

Thermostat Location

Thermostats only know the temperature of its location. If it’s right next to a drafty window or door, it might indicate that it’s hotter throughout your whole home, causing the HVAC system to run continuously.

Aging or Inadequate HVAC

If your HVAC system is the wrong size or is nearing the end of its lifespan, it might struggle to maintain comfortable temperature levels in your home. Particularly if you’ve made changes, such as knocking down walls to open up the floor plan or installing new insulation, your HVAC system may have to work harder.

5 Potential Fixes for Uneven Temperatures

Once you know what’s causing your temperature issues, you can take some steps to fix them:

• Seal ducts: Have a professional inspect and seal your ductwork. An HVAC technician can close up cracks and disconnected joints, so more air reaches its destination.
• Opt for HVAC zoning systems: Multi-level homes may benefit from an HVAC zoning system, with multiple thermostats. That way, you can control the temperature of the upstairs separately from the downstairs.
• Use a smart thermostat: A smart thermostat uses room sensors so you can maintain steady temperatures throughout your home. And, you can set up schedules so that the thermostat automatically adjusts temperatures to match your needs.
• Improve your insulation: Adding blown-in insulation to your attic or weatherstrips over windows can improve your home’s ability to hold onto air and maintain comfortable temperatures.
• Get a system evaluation: An HVAC professional can evaluate your system, adjust the blower motor, check refrigerant levels, and ensure it’s working appropriately. If the system is older, a technician can help you determine if it’s time for a replacement.

FAQs

Why is one room in my house always hotter than the others?

A single room that is hotter than the rest of the house is usually due to its location and how much sunlight it gets during the day. Rooms with lots of windows will typically be warmer than others.

Can closing vents in unused rooms balance temperatures?

No, closing vents to unused rooms isn’t recommended. Closing vents increases the pressure in your ductwork, making temperature imbalances worse, and the room has high moisture levels.

Can a smart thermostat fix uneven temperatures?

If you choose a smart thermostat with multiple remote room sensors, you can maintain steadier temperatures than a unit with a single thermostat reading.

Is uneven cooling a sign I need a new AC?

Not always. Uneven cooling can be due to several issues, such as clogged air filters or poor insulation. However, if the system is older or the wrong size for your home, uneven temperatures can be a sign it’s time for a replacement.