It’s not unusual for an air conditioner to struggle during a heat wave. In most cases, it’s not broken. It’s simply being pushed beyond its design limits. Understanding why this happens will put your mind at ease.

A 20-Degree Difference

Most residential ACs are designed to cool a home to a maximum of 20°F below the outdoor temperature. This is more than enough throughout most of the summer season. Unfortunately, this means that if it reaches 100°F outside, your AC can only cool your home to 80°F. This feels uncomfortable compared to what you’re used to.

Reduced Heat Exchange Efficiency

Your air conditioner keeps you cool by moving indoor heat outside. This process relies on a difference in temperature between the refrigerant and the air outside. When it gets extremely hot outside, it’s much harder for your AC’s condenser to get rid of the heat it collects from inside. To compensate for this, the system runs nonstop. This leads to the compressor overheating, which causes it to temporarily shut down in an attempt to protect itself.

The Humidity Load

High humidity often comes with a heat wave. This forces your AC to act as a dehumidifier before it can effectively cool your home, which requires a substantial amount of energy. Furthermore, it causes your system to lose its ability to focus solely on lowering temperature.

Under-Sizing

When engineering standard HVAC systems, engineers follow what is called the 98% rule. This means that they size systems to handle 98% of the usual summer temperatures for specific regions. It simply isn’t designed to handle that other 2% of intense heat. If they sized every AC to handle the occasional heat wave, the system would be highly inefficient. It would also struggle to reduce humidity throughout the rest of the summer season.

Maintenance and Performance Issues

You may notice minor flaws in your AC during a heat wave that go unnoticed during the rest of the summer months. If there’s dust on the outdoor condenser coils, it will act like insulation, trapping heat inside your system. Dirty air filters restrict airflow. This results in the indoor evaporator coils freezing, even during a heat wave. Routine maintenance helps minimize these issues.

Solar heat gain also plays a factor in how warm your home is during a heat wave. Sunlight coming through the windows can turn into heat faster than the AC can keep up.

While your AC will struggle to keep you comfortable during a heat wave, it should handle average summer heat beautifully. If your system is older and struggles throughout the entire summer season, it may be time for a replacement. Call Sky Heating, AC, Plumbing & Electrical today to learn more about our AC replacement services in Tualatin, OR.