Your  AC may be unable to reach temperatures below 75°F due to various factors, including incorrect sizing, high outdoor temperatures exceeding 95°F, a clogged or dirty air filter, a tripped breaker, ductwork that is leaking air, an obstructed outdoor unit, faulty wiring in the thermostat, depleted thermostat batteries, or refrigerant leakage.

It could also be attributed to a blocked condensate line, frozen evaporator coils, a malfunctioning compressor, or an ageing air conditioning unit.

Depending on your location and personal preference, the optimal room temperature for an air conditioner typically ranges from 68 to 75 degrees Fahrenheit (°F).

However, there are instances when the air conditioner struggles to lower the temperature below 75°F, leaving you wondering why this is happening.

Certainly, when your air conditioner cannot cool your space adequately, especially if it cannot bring the temperature below 75 degrees, there is likely an issue that needs to be addressed.

I will provide explanations for each of these problems and their corresponding solutions to help you restore efficient cooling to your air conditioning system.

Why Your Air Conditioner Won’t Cool Below 75 Degrees

1. New Air Conditioner Won’t Cool Below 75 Because It’s the Wrong Size

If you've recently installed or purchased a new air conditioner but find that it cannot lower the temperature below 75 degrees, the likely issue is that it is the wrong size, typically undersized. Such an air conditioner will have limitations that prevent you from setting the thermostat temperature lower than 75 degrees.


To address this problem, it's crucial to match your air conditioner's capacity (measured in BTUs or British Thermal Units) with the size of your room. If the unit is undersized, it won't effectively cool your space, and if it's oversized, it may struggle to remove humidity, potentially leading to mould growth.

Below, you'll find a guide to help you determine the appropriate air conditioner size for most window-mounted and portable home air conditioners:

2. Extremely Higher Outdoor Temperature

Your air conditioner is generally effective at cooling when the outdoor temperature is below 92 degrees Fahrenheit, but it may struggle to perform properly when it exceeds 75 degrees. In essence, the air conditioner is designed to lower the indoor temperature by approximately 20 degrees below the outdoor temperature.

For example, if the outdoor temperature is 95 degrees, the air conditioner will aim to bring the indoor temperature down to around 75 degrees. However, when the outdoor temperature climbs to 96 degrees or higher, it becomes challenging for the air conditioner to maintain a cooling temperature below 75 degrees.


While you have limited control over the outdoor temperature, there are steps you can take to mitigate its impact indoors.

You can try minimizing the heat gain inside your home by closing windows and doors to prevent warm air from entering.

Additionally, using fans in conjunction with your air conditioner can help distribute cool air more effectively, enhancing your comfort.

3. Dirty Air Filter

Unclean air filters can hinder the proper functioning of your air conditioner and, in some cases, even trigger an automatic shutdown. Consequently, a dirty air filter might be the reason why your AC cannot lower the temperature below 75 degrees.

When the air filter becomes clogged with dirt, it restricts the flow of cold air, leading to a decrease in cooling efficiency.


If you find that your air filter is dirty, the solution is to replace it. Most manufacturers recommend changing the air conditioner filter every 1 to 2 months, depending on how frequently you use the AC. This regular maintenance ensures that your air conditioner operates at its optimal performance level and can effectively cool your space.

4. Tripping Breaker

At times, achieving efficient cooling with your air conditioner can be challenging when the circuit breaker keeps tripping. This issue typically occurs when the circuit breaker is loose or faulty, causing it to shut off. In such cases, it's important to check the status of the unit's circuit breaker.


  1. Examine the Circuit Breaker: First, inspect the circuit breaker to see if it has tripped. If it has, you can reset it to restore power to the air conditioner.
  2. Contact a Local Electrician: However, if the circuit breaker continues to trip after resetting it, it's advisable to contact a local electrician for further examination and repair. A professional electrician can identify the root cause of the problem and ensure that your electrical system is functioning safely and efficiently.

5. The Air Conditioner Will Not Cool Below 75 Due to Leaky Ductwork

When your ductwork has cold air leaks, it can be challenging for the air conditioner to maintain a very low temperature indoors. Consequently, it is crucial to identify and seal any sources of air leakage to ensure that your AC can effectively cool your space within the desired temperature range.


  1. Inspect the Ductwork: Begin by examining your ductwork for any spots where cold air may be escaping. These leaks can often be found at joints, connections, or damaged sections of the ducts.
  2. Seal the Leaky Spots: If you identify any leaky spots, you can seal them using appropriate duct sealing materials, such as duct tape or mastic sealant. Make sure to follow recommended sealing practices for your specific type of ductwork.
  3. Consult an HVAC Expert: If you are unable to locate or seal the leaks yourself, or if you suspect that the issue is more extensive, it's advisable to consult an HVAC (Heating, Ventilation, and Air Conditioning) expert. They can conduct a thorough inspection, identify all sources of leakage, and provide professional sealing solutions to optimize your air conditioner's performance.

Pros and Cons of  Air Conditioners


  • Temperature Control
  • Improved Air Quality
  • Enhanced Comfort
  • Humidity Control:


  • Energy Consumption
  • Initial Cost
  • Maintenance
  • Environmental Impact:

Differences Between Air Conditioners and Midea Air Conditioners

Air Conditioners

Features and technologies can vary significantly among different brands and types of air conditioners. These may include energy efficiency, cooling capacity, smart functionality, and air purification capabilities, depending on the specific model.

Midea Air Conditioners

Midea air conditioners often incorporate the latest technologies and features, such as inverter technology for energy efficiency, WiFi connectivity for remote control, and various cooling modes for user comfort.

Alternative to Air Conditioner


The Hisense R32 Inverter Air Conditioner (TUGS) boasts a 5-star energy rating certified by Suruhanjaya Tenaga. It features an integrated Plasma Generator designed to eradicate bacteria and formaldehyde. The air conditioning unit utilises golden fins in both its blower and compressor components, ensuring optimal cooling efficiency. 

Furthermore, it operates with minimal noise and offers precise temperature regulation. Additionally, this particular model includes a 3-year general warranty and a 10-year warranty for the compressor.

Moreover, the use of gold fins in the cooling coil, as opposed to the standard blue ones, enhances durability and longevity.

In terms of warranty, this model provides a 2-year general warranty along with a commendable 5-year warranty for the compressor, assuring consumers of its reliability and performance.

6. Blocked Outdoor Unit

It's crucial to ensure that the outdoor unit, particularly the condenser, receives proper airflow. Any obstructions, such as debris, branches, furniture, or shrubs, should be removed to maintain adequate airflow.


  1. Inspect the Area: Regularly check the area around the outdoor unit to ensure that there are no obstructions hindering airflow. Look for loose branches, overgrown shrubs, fallen leaves, and any other debris.
  2. Clear Obstructions: Trim and remove any loose branches or unruly shrubs that may be blocking the condenser unit. Additionally, clear away dirt or debris piles near the unit.
  3. Move Outdoor Furniture: If you have outdoor furniture or objects placed near the air conditioner that could obstruct airflow, relocate them to create an unobstructed path for air to flow around the condenser.

7. Faulty Thermostat Wiring

When there is a wiring fault in your air conditioner's thermostat, it can become difficult to set and control the temperature correctly. These wiring issues can lead to thermostat failure, making it challenging for the air conditioner to cool your space effectively.


  1. Examine the Thermostat Wiring: If you have some familiarity with thermostat wiring and can safely do so, you can take out the thermostat and inspect its wiring. Compare the wiring against the design specified in the thermostat's manual.
  2. Contact an HVAC Expert: If you notice any discrepancies or are uncertain about the wiring, it's advisable to contact a professional HVAC expert. They have the expertise to identify and rectify wiring faults accurately, ensuring that your thermostat operates correctly and allows your air conditioner to function optimally.


In conclusion, when your air conditioner struggles to bring the temperature below 75 degrees Fahrenheit, there are several potential culprits to consider.

These issues range from incorrect sizing, outdoor temperature limitations, dirty air filters, tripped circuit breakers, leaky ductwork, obstructed condenser units, faulty thermostat wiring, and various other factors.

Identifying the specific cause behind your AC's performance limitations is essential for restoring efficient cooling.

Addressing these issues often involves routine maintenance, proper sizing, cleaning or replacing air filters, checking circuit breakers, sealing ductwork, and ensuring unobstructed airflow around the outdoor unit. In some cases, it may require the expertise of HVAC professionals to diagnose and fix complex problems.

By understanding these common factors and their respective solutions, you can take proactive steps to ensure your air conditioner operates effectively, maintaining a comfortable indoor temperature even on the hottest days.

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