What makes one car's air conditioner create cold air so much quicker than the other car?

My 2008 Hyundai Santa Fe’s air conditioning takes 20+ minutes to cool the car down - on a hot day it almost seems like it’s not working (but it is, just slowly). This is even after I’ve taken it to a place to have the Freon refreshed. On the other hand my 2001 BMW’s air conditioner instantly creates very cold air. What makes one car’s air conditioner create cold air so much quicker than the other car?

Possibly you could be low on refrigerant. Take it to the shop and have it checked out.

Another explanation is that your car, while not incredibly cheap, is still cheap. Cheap cars would tend to have cheap components. Just one of the trade offs.

A lot of things. Different design of the baffles; more, and more efficient venting; the fact that a BMW probably has rear seat vents. Also, the fact that the interior of the BMW is probably a smaller space. Are the cars different colors? If the Santa Fe is navy, and the BMW is cream, the Santa Fe may actually be hotter inside to begin with. Also, if one has cloth interior, and the other has vinyl or leather, the cloth one may hold heat more efficiently. If they have similar-sized engines, but one is powering a smaller car, then the one in the smaller car can devote more power to the AC. You don’t realize it’s happening, but the AC has a clutch, and every time the engine is under a certain load, the AC shuts itself off so the engine won’t stall. It may happen more often to a bigger vehicle with a proportionately smaller engine. I had a Geo Metro with a 3-cylinder engine. It was a really small car, but also a small engine, and the AC cut out every time I went up a big hill (something southern Indiana has lots of).

Those are all the non-problem things I can think of off the top of my head.

Problem things are a stuck-open radiator thermostat that isn’t allowing the engine to warm up, so it isn’t performing efficiently, or any other problem that is making the engine inefficient, like glazed spark plugs. If they haven’t ever been changed, change them. Every 4-6 years is about right for needing new plugs. You could also be low on radiator coolant. If the engine is running hot, the AC compressor may come on and off rapidly.

If the compressor is coming on and off, it will still blow air, it just won’t blow cooled air, although if it is cycling on and off rapidly, you won’t notice, because there’s enough cool air still in the vents.

It probably is a combination of the non-problem reasons, since you say you just had it checked.

Look up the weight of the vehicles and the power of the engines, and you’ll probably find that the BMW has more power than the Santa Fe.

It just sounds like the AC on the Hyundai is broken. I would expect that its AC was never as beefy as the BMW’s, but 20 minutes to cool the car down is just ridiculous. Low refrigerant is just one of many problems it could be. You probably ought to just take it somewhere that can put some effort into diagnosing it.

While we’ve got our crystal balls out, though, if it actually is eventually getting cold and the refrigerant levels are indeed good my guess would be the condenser fan. The condenser is at the front of the car, either next to the radiator or in line with it. In order for the AC to work, there needs to be air passing through it. When you hit the AC button, it turns a fan on (either the same as the radiator cooling fan or a separate one). If the fan isn’t working, the AC will work just fine at highway speeds, but will work poorly to not-at-all when driving around town. But that’s just a guess. You probably need someone to actually look at it.

Dirty cabin air filter? Mine was just replaced and the mechanic mentioned I should see faster AC cooling.

Low freon, restricted air flow over the evaporator, restriction in expansion valve, plugged dryer. You really need to have the system checked. If you open the hood and see that the lines are very cold comming out of the cars interior, hot comming out of the compressor and only warm comming out of the condensor then the cabin filter might be the first place I would look. Other than that proffessional service is likley needed.

I once accidentally put more freon - it made it longer to cool down too. Check the freon. I could be high or low - neither is good.


No matter when someone says they have checked the refrigerant a fresh mechanic will always recheck it. Been doing this work for over 45 years and I don't take anybodys word for anything.

Have you measured the temperature of the air coming out of the vents?

In the late 90’s, I had a 1988 Toyota Corolla (4 cylinder) that would blow 35 deg F air. My brand new 1997 GMC Truck A/C would only blow 45 deg F air.

The Corolla was not as well insulated or sealed, so it needed the colder air.

I didn’t know what a Santa Fe was, but a quick Google tells me that it’s some sort of SUV. It could be that there’s simply a lot more air mass to cool down than the BMW. What we do in this hot environment (check my location) is to crack the windows when turning on the AC. This lets the hot air escape while being replaced with cooler air.

One possibility is that the controls for the Hyundai aren’t properly set for maximum cooling. Make sure that the recirculate/fresh air intake is set to recirculate.