Air conditioner not cooling house – reasons and solutions

As the summer months approach, a fully functional air conditioner is not just a luxury but a necessity. But few things are more frustrating than when your air conditioner refuses to cool your home.

Understanding the common reasons behind this issue and knowing the appropriate solutions can save you time, money, and a great deal of discomfort. In this article, we will explore the most frequent causes of air conditioner malfunctions and provide practical solutions and advice.

So, let’s get started.

Air conditioner is not cooling the house: 5 common reasons

Let’s look at five common reasons you might find your air conditioner is not cooling the house properly.

1. Dirty or blocked outdoor unit: The outdoor unit of your air conditioner is exposed to the elements, often accumulating dirt, debris, and vegetation that can obstruct airflow.

2. Improperly sized AC unit: An air conditioner that is too large or too small for your space can cause cooling issues. An undersized unit will struggle to cool a large room, while an oversized unit will cycle on and off too frequently, failing to maintain a consistent temperature.

3. Clogged air filters: Air filters trap dust, pollen, and other contaminants, but when they become clogged, they restrict airflow, reducing the AC’s cooling efficiency.

4. Low refrigerant levels: Refrigerant is crucial for cooling, as it absorbs heat from the indoor air and releases it outside. If your AC is blowing warm air, it might be low on refrigerant due to a leak or improper charging during installation. Signs of low refrigerant include ice buildup on the unit and hissing sounds.

5. Thermostat issues: A malfunctioning or improperly set thermostat can prevent your AC from cool

Air conditioner is not cooling the house: 5 solutions

Let’s now look at five solutions to employ if your air conditioner is not cooling the house.

1. Clean and maintain the outdoor unit: Regularly check for and remove any debris, leaves, grass, or other blockages around the unit. Ensure at least 18 inches of clear space around the unit to allow proper airflow. For thorough cleaning, use a foam coil cleaner and gently rinse the unit with a hose, or hire a professional technician for a more detailed maintenance service.

2. Ensure the unit is appropriately sized: An undersized unit will struggle to cool the area, while an oversized unit will short cycle, leading to inefficient cooling and increased wear and tear. Consult an HVAC specialist to evaluate your space and recommend an appropriately sized unit based on factors such as room size, window placement, and sunlight exposure.
   
   
3. Replace or clean air filters: Check the air filters at least once a month and clean or replace them as needed. Clean filters ensure air flows smoothly through the system, allowing for efficient cooling. This simple maintenance task can significantly improve your air conditioner’s performance and extend its lifespan.
   
   
4. Refill refrigerant levels: Refrigerant is essential for absorbing heat from your home and expelling it outside. If your AC is low on refrigerant, it could be due to a leak or improper installation. Signs of low refrigerant include ice buildup on the unit and unusual noises like hissing or bubbling.
   
   
5. Check and adjust the thermostat: First, make sure the thermostat is set to ‘AUTO’ instead of ‘ON’ to ensure the fan runs only during cooling cycles. If adjusting the settings doesn’t resolve the issue, replace the thermostat batteries.

When to call a professional?

Let’s work through some troubleshooting before you call in a professional.

• Start with a quick electrical check to ensure your air conditioner has power. Confirm there’s no power outage in your area before calling for HVAC repair. Check the circuit breaker box; if the breaker for your HVAC unit has tripped, reset it and see if your AC starts working again. If the circuit continues to trip, there is a safety problem – call an HVAC service technician or an electrician. Additionally, check the on/off switches near both the indoor air unit and the outdoor compressor, as these can hold a lot of electricity.

• Next, take a closer look at the thermostat. Ensure it is set to cool, not heat, as it can sometimes be accidentally switched. If your thermostat uses batteries and appears dead, replace them. Be mindful of outdoor temperatures – if it’s extremely hot outside, your AC may struggle to cool your home efficiently. This doesn’t necessarily indicate a problem with your AC – you may simply need to supplement it with fans to achieve the desired comfort level.

• Finally, assess the AC system itself. Inspect the air filters. If they’re dirty, your AC will have difficulty circulating cool air. Check the AC condensate drain line and drain pan for clogs, especially if there is water in the pan. Ensure that air vents are not covered, as blocked vents can negatively impact your AC’s performance. Additionally, ensure the outside air compressor is clear of debris, maintaining at least three feet of clearance around it.

If your air conditioner still isn’t working after these steps, contact a reliable HVAC company to diagnose and fix the problem.

Air conditioner maintenance tips

Let’s now look at some air conditioner maintenance tips.

• Turn off the power and clear all debris: Begin by turning off the power to your air conditioner. Switch off the circuit breaker and unplug the unit. Disconnect the condenser unit using the 240-volt disconnect box if available. Allow the system to cool down completely before proceeding to avoid the risk of electric shock. Once the unit is cool, open the outdoor unit and clear any debris from the condenser floor using a wet/dry vacuum or by hand. Remove leaves and other debris from the condenser fins to ensure optimal airflow.

• Clean and replace the AC filters: AC filters should be replaced every 90 days, but more frequent changes are necessary if you live in a dry climate, have allergies, or own pets. To clean the filters, remove them from the unit and use a dry cloth or wet/dry vacuum to eliminate dust and debris. Scrub the filter with a solution of one teaspoon of detergent per litre of water or soak it in the solution for an hour. Rinse thoroughly with a garden hose and allow the filter to dry completely before reinstalling it in the HVAC system.

• Check and clean the evaporator and condenser coils: The evaporator and condenser coils must remain clean for your air conditioner to function properly. Inspect the coils annually for dust and debris. Locate the evaporator coil near the indoor air handler or furnace and the condenser coil on the outside unit. Clean the coils with a soft bristle brush, AC solvent, or mild detergent, and let them dry completely before reassembly. Clean coils enhance cooling efficiency and reduce energy bills, as dirty coils can increase energy usage.

• Straighten coil fins and unclog drain channels: Coil fins help remove warm air from the system. If they are bent, use a fin comb to straighten them. Lubricate the fins with mild dish soap and gently comb them straight from the bottom up. To prevent clogging, clean the condensate drain line. Remove and clean the drain pan, then attach a wet/dry vacuum hose to the drain line and secure it with duct tape. Run the vacuum to clear debris. Flush the line with water and a mixture of warm water and white vinegar to clear any buildup.

• Ensure proper airflow and level the condenser unit: Proper airflow is crucial for efficient AC operation. Inspect ductwork for debris, leaks, and crimps. Ensure outdoor equipment is unobstructed, furnace filters are clean, vents are open, and the unit is free from dirt. Use a level tool to check for balance and adjust as needed using gravel, adjustable legs, or temporary wood shims. For major adjustments, consider hiring a professional technician to ensure proper levelling and avoid potential damage.

Conclusion

Regular maintenance and timely troubleshooting are essential for keeping your air conditioner running efficiently and your home comfortably cool. By following the outlined steps, you can address common issues and enhance the performance of your AC unit. However, for more complex problems, always consult a professional to ensure the longevity and reliability of your air conditioning system.

When it comes to air conditioning, Daikin is a world leader. We offer a wide range of HVAC solutions tailored to meet diverse building requirements, including residential, commercial, and industrial. Daikin has a full lineup of split systems, packaged units, ductless mini-split systems, VRF (VRV) systems, and more, each designed to deliver exceptional performance, energy efficiency, and comfort. With innovative, pioneering technology and exceptional service, Daikin has sold millions of systems in 140 countries. If you would like to find out more about Daikin’s products, contact us today.