On a 90-degree day, nothing feels better when you get into your car than a cool breeze flowing through the vents. It can help a little of your stress disappear as you feel the temperature fall. 

Yet sometimes it might feel as if it takes longer for that to occur. You keep it on full blast, wondering where the cool air is. 

Then there are efficiency issues – does AC operation mean less fuel efficiency? What if you want both? 

No matter what you’ve heard about keeping your car’s AC running efficiently, we bet there are a few myths you may still believe. Let’s get to the nitty-gritty of a car’s AC system and find out how to stay cool all season long. 

How a Car’s AC System Works

It’s actually a fairly simple process. 

A car’s air conditioning system works by removing heat from inside the car and expelling it outside, making the air inside cooler. It uses a special substance called refrigerant that circulates through the system. The process starts with the compressor, which is powered by the car’s engine. The compressor squeezes the refrigerant gas, increasing its pressure and temperature.

Next, the hot, high-pressure refrigerant gas moves to the condenser, which is located at the front of the car near the radiator. As air flows over the condenser, the refrigerant releases its heat and changes into a high-pressure liquid. This cooled liquid then travels to an expansion valve, where it quickly expands. This expansion lowers its pressure and temperature, turning it into a cold, low-pressure liquid.

The cold liquid refrigerant then goes to the evaporator, which is inside the car’s dashboard. The car’s blower fan pushes warm air from the interior over the evaporator coils. The refrigerant absorbs the heat from the air, causing it to evaporate into a gas. This process cools the air, which is then blown through the car’s vents, making the interior cool and comfortable.

The refrigerant, now warm and low-pressure again, goes back to the compressor, and the cycle starts over. This continuous loop removes heat from the car’s interior and expels it outside, keeping the car cool. Additionally, as the evaporator cools the air, it also removes moisture, dehumidifying the car’s interior. The condensed water from this process drains outside the vehicle.

Let’s Talk Refrigerant – An Essential Part of an AC System

As you’re reading above, you’ll notice refrigerant stands out as an essential part of the cooling process. That makes it one of the important fluids you should inspect regularly throughout the cooling system, as it’s crucial for your car’s AC system, helping cool and dehumidify the air inside your vehicle. Here’s what you need to know about refrigerant:

How to Know if Your Car Has Proper Refrigerant

First, check if your car’s AC system is blowing cold air when set to maximum cooling. If it is, you likely have enough refrigerant. Pay attention to how quickly your car cools down; if it takes longer or the air isn’t as cold as it used to be, the refrigerant level might be low. Some cars have a sight glass on the refrigerant lines where you can see the refrigerant flow; bubbles in the sight glass can indicate low levels. During routine maintenance, a mechanic can use gauges to check the refrigerant pressure. Proper pressure readings indicate the right amount of refrigerant.

How Often Should Refrigerant Be Checked?

It’s a good practice to have your car’s AC system checked at least once a year, ideally before the hot summer months. This ensures the system is in good working order and can help detect any issues early. If you notice any decline in AC performance, unusual noises, or if the air isn’t as cold as it should be, have the refrigerant levels checked immediately.

What Happens if Refrigerant is Low?

Low refrigerant levels mean the AC system cannot cool the air effectively. You’ll notice that the air from the vents is not as cold as it should be. The AC compressor relies on refrigerant for lubrication and cooling. Running the system with low refrigerant can cause the compressor to overheat and fail, leading to expensive repairs. The evaporator removes moisture from the air, but low refrigerant levels reduce its efficiency, leading to higher humidity inside the car. Additionally, low refrigerant often indicates a leak in the system. Refrigerant leaks can be harmful to the environment and need to be addressed promptly by a professional.

Tips for Maintaining Proper Refrigerant Levels

Include AC system checks in your regular vehicle maintenance schedule. Have a certified technician inspect your AC system annually, especially before summer. If you suspect a refrigerant leak or experience reduced cooling, seek professional help immediately to prevent further damage and ensure optimal performance.

AC’s Effect On Fuel Efficiency

According to the US Department of Energy, running your car’s AC system is the main contributor to reduced fuel economy in hot weather. Of course, there are a number of factors that impact that reduction: outside temperature, humidity, intensity of the sun, to name a few. But in very hot conditions, AC use can reduce a conventional vehicle’s fuel economy by more than 25 percent. EVs and hybrids can be even more. 

The refrigerant in your car’s AC system indirectly affects fuel efficiency through its role in the AC compressor’s operation. When you turn on the AC, the compressor pressurizes the refrigerant and circulates it to cool the air. This process requires additional engine power, increasing fuel consumption. The harder the compressor works, the more fuel the engine uses.

Having the right amount of refrigerant is crucial for efficient AC operation. When refrigerant levels are optimal, the AC system works efficiently, cooling the air with minimal strain on the compressor. This results in a moderate increase in fuel consumption when the AC is on.

If the refrigerant levels are low, the compressor has to work harder to cool the air, leading to higher fuel consumption. The engine must produce more power to drive the overworking compressor, using more fuel in the process. Too much refrigerant (an overcharged system) can also cause problems. Excess refrigerant increases pressure and strain on the compressor, making the system less efficient and consuming more fuel.

What’s the answer? How do you ensure efficiency throughout the season? 

It starts with regular maintenance. 

Regular maintenance of the AC system, including checking and refilling refrigerant levels, ensures it operates efficiently. An efficient AC system requires less power from the engine, helping maintain better fuel economy. A well-maintained compressor that runs smoothly and efficiently uses less energy, conserving fuel. Additionally, ensuring there are no leaks or blockages in the AC system helps maintain proper refrigerant levels and optimal compressor performance, both crucial for fuel efficiency.

We also suggest protecting your vehicle no matter where you are. Park in shaded areas or use sunshades to protect your interior. 

Open the windows when you first get into your car on a hot day. Let the open windows air out some of the hot air while you start your vehicle, then allow the AC to gradually cool the interior down. This puts less demand on the AC and helps cool your car faster. 

Staying Cool All Summer Long

Efficiency starts by understanding your vehicle a little better. Want a cooler, more comfortable drive? It starts with creating a well-maintained vehicle, one that drives well in any road condition. 

How can we help you? Have an AC problem? Have questions about how air conditioning works? We’re here to help you with all of your needs.