Why Does My AC Only Work in Some Parts of My House?

Jun 15, 2021

When your air conditioner only cools a few rooms of your home during the summer, you might find yourself avoiding whole sections of your house. Instead of restricting yourself to a couple of rooms, you can take action to ensure you’re comfortable no matter where you are in your home. By knowing some of the primary reasons behind an AC cooling only a few rooms in a house, you can find a solution and get back to enjoying every part of your home.

Find out more about the top eight reasons why your AC is only partially cooling your home and what you can do to get your AC working at full capacity again.

Problem 1: Obstructed Vents and Ineffective AC

One of the simplest reasons your AC is only working in certain rooms is vent obstructions. This issue can take three different forms:

  • Closed vents: As you might expect, air can’t blow through a closed vent. Check the settings on your vents to ensure they are not preventing air from being released into your room.
  • Furniture vent obstruction: You may also find furniture or another obstruction placed in front of your vents. This will restrict airflow and prevent your room from feeling comfortable. Try to keep furniture at least 6 inches away from vents on your walls and floors.
  • Internal vent blockage: If all your vents are open and clear of outside obstructions, you might have something inside the vent blocking the airway. Removing debris and other obstructions from the ducts leading to your vent can help you restore air to a room.

Solution: Check Your Vents

Before worrying about your AC functioning, check your vents. This solution could be as simple as opening up your vents lever to let air into your rooms.

Problem 2. Leaky Doors and Windows

When one room or area in your home doesn’t feel comfortable, it might not be an issue with your AC system at all. Instead, you may have cracks or leaks in your windows, doors, or insulation. These cracks will let the warm air in while letting your comfortable air conditioning escape. As a result, this area of your home (and surrounding rooms) will not feel comfortable. This issue is common for rooms near your attic or garage.

Solution: Home Sealing Services

Home sealing services will find and detect areas of your home that let your AC escape. Then, your professional will seal off these cracks and leaks to help your home feel more comfortable.

Problem 3. Too Small or Large HVAC System

The size of your HVAC system plays a key role in how well it cools your entire home. If you’ve always had trouble with keeping certain rooms cool, you might want to check the size of your AC unit.

An AC unit that’s too large for your home can end up running for only short periods, resulting in it only cooling select areas of your home. In contrast, a unit too small for your home can struggle to deliver the amount of air required to cool your entire home, leading to only parts of your home feeling consistently cool.

Solution: HVAC Size Check

If you think your air conditioning system is too large or too small, consult a professional. It is crucial to have the right-sized HVAC system for your home.

Problem 4. A Damaged AC Fan Motor

AC units rely on a fan to properly circulate your home’s cool airflow. If your fan’s motor isn’t working as intended, it will not be strong enough to adequately push air through your distribution system. As a result, the rooms closest to your HVAC system will feel cooler, while the rooms farthest away will be warmer.

Solution: AC Repair or Replacement

A damaged fan motor will require professional AC repair or replacement services.

Problem 5. Damper or Zoning Issues

HVAC zoning systems (also known as “zoned HVAC”) work by using dampers to allow multiple climate controls. For example, you might have a separate thermostat controlling your upstairs temperature versus your downstairs temperature. When you set your temperature higher upstairs, the dampers will shift to redirect air downstairs. HVAC zoning is often the solution to many home climate troubles. However, a few potential hiccups can cause your HVAC zoning to prevent comfort in one area of your home:

  • Thermostats: You will want to ensure both zones of your homes have well-functioning, calibrated thermostats. If your thermostat is misreading the climate of your room, it will not be able to adjust the temperature according to your preferences.
  • Dampers: If your dampers become damaged or stuck, they will not be able to regulate your zoned HVAC climates properly.

Solution: Zoning Inspection and Repairs

An HVAC professional can repair your thermostats or dampers to ensure your zoned HVAC system is working properly.

Problem 6. Clogged Air Filters

A clogged air filter is a common culprit when an air conditioner stops producing enough cool air for your entire home. When air filters get clogged with dust, dirt, and other debris, your AC unit has to fight to pass air through. As your system struggles to circulate air, the room’s closest to your system will still receive cool air, while the rest of your home will grow warmer.

Solution: Clean or Replace Filters

In this case, you may simply need to clean or replace your air filters. However, the stress of clogged air filters can quickly cause larger system issues, so it is essential to maintain your recommended air filter replacement cadence.

Problem 7. Dirty Evaporator Coils

Another common reason your AC isn’t pushing enough cool air into your home is due to dirty or failing evaporator coils. These coils are crucial to cooling your home properly, and when they get covered in bacteria, dust, and dirt, they can start to work less efficiently. The dirt serves as a barrier between your refrigerant and the air your system circulates.

Solution: Annual AC Maintenance

Your HVAC coils are sensitive components that can become easily damaged. Thankfully, an expert will check and clean your entire unit during your annual maintenance visit—including your evaporator coil.

Problem 8. Home Updates and HVAC Design

Every home is built with custom ductwork and HVAC design tailored to the needs of the building. However, if you (or the people who sold you your home) changed an area of the layout, it could lead to an ineffective HVAC design. Let’s take a look at some examples:

  • Certain parts of your home—such as the attic and the garage—are often not factored into your ductwork or system design. If your sellers decided to flip an attic or garage space to create a new room in your home, this addition could throw off your air distribution and needs.
  • Similarly, if you extend one area of your home, it may require more air conditioning than your HVAC design factored in. The extension may lead to ineffective air conditioning in that room and surrounding areas of your house.

Solution: Design Adjustments or Mini-Split Installation

There are two ways to address HVAC design issues:

  • First, you may consult an HVAC design professional and see how much it would cost to rework your existing HVAC system to accommodate the change in design.
  • Second, you may consider adding a ductless mini-split system to the extended area of your home. Ductless mini-split systems are like smaller versions of your HVAC system. They work as air conditioners in the warmer seasons and heaters in the colder seasons—but they only work in one part of your home. Think of these as HVAC extension units.

Turn to Newcomb and Company for HVAC Repair in Raleigh and Wilmington

Newcomb and Company has all of the repair, replacement, and maintenance services needed to get your AC unit working efficiently throughout the summer. As a premier HVAC company serving Raleigh, Wilmington, and surrounding areas, we are ready to address your air conditioner service needs. Many of our customers enjoy our high-quality, fast service and our coupons/promotions. You can even contact our emergency AC repair technicians for 24/7 priority service.

Review our HVAC repair services today. For a free estimate or the answers to all of your questions, please contact our experts today!


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