CX-5 Air conditioning performance in hot weather
- Thread starter BWJ
- Start date
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- 2022 CX-9 Signature
Works the coldest on recirculate. Your cooling down the cabin air and not the fresh hot outside air. Live in central Florida.
Take it from an AC pro - really, I don't mean ACME Plumbing and Air tech, I mean a civic engineer building 25 story buildings - unless you need outside air for some reason, there's no reason not to have it set on recirculate. Why introduce hot outside air in to you system?
Except when the car has been sitting in the sun all day and the interior temp is 120+.
The outside air is cooler, once the inside cools down switch to recirc.
- I live in NW Florida 5 miles from the Gulf of Mexico (hot and humid).
- Not exactly sure how your car's "AUTO" mode is set up. The '03 Protege5 has manual switching for either recirculate or exterior air.
- First, when getting into the (extremely hot cabin) I would suggest to open the windows some to force the hot air out with your AC and blower fan on as you drive - hot air rises and stratifies top down so you want to get that hot upper interior air moving out as quick as you can.
- If you are fully enclosed in the car's cabin with no air leaving the interior of the car to the outside, an (extreme) example is that it's like you're trying to blow air into a soda bottle and no air is escaping or moving.
- I noticed on the '03 Protege5 into and behind the rear panels there looks to be some air vents that were designed into the car to allow interior air to flow thru to the outside to avoid this back-pressure bottled-up air effect.
- IMO - If you're stuck in traffic or moving slowly, I'd have the AC on in recirculate with the windows cracked open some to let the hot upper air out and close them when the car cools down to bearable limits.
- If you're out on the highway travelling at higher speeds, I'd set it for outside air until it gets most of that hot air out quickly (with the blower and AC on) and then go to recirculate.
- Then again, maybe your car's 'AUTO" feature is designed to do this all this by itself.
- Not exactly sure how your car's "AUTO" mode is set up. The '03 Protege5 has manual switching for either recirculate or exterior air.
- First, when getting into the (extremely hot cabin) I would suggest to open the windows some to force the hot air out with your AC and blower fan on as you drive - hot air rises and stratifies top down so you want to get that hot upper interior air moving out as quick as you can.
- If you are fully enclosed in the car's cabin with no air leaving the interior of the car to the outside, an (extreme) example is that it's like you're trying to blow air into a soda bottle and no air is escaping or moving.
- I noticed on the '03 Protege5 into and behind the rear panels there looks to be some air vents that were designed into the car to allow interior air to flow thru to the outside to avoid this back-pressure bottled-up air effect.
- IMO - If you're stuck in traffic or moving slowly, I'd have the AC on in recirculate with the windows cracked open some to let the hot upper air out and close them when the car cools down to bearable limits.
- If you're out on the highway travelling at higher speeds, I'd set it for outside air until it gets most of that hot air out quickly (with the blower and AC on) and then go to recirculate.
- Then again, maybe your car's 'AUTO" feature is designed to do this all this by itself.
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- CX5 GT
Thats what I do in Phoenix 105 - 110F.
Open the windows half way and use auto. The AC system turns air recirculation during the summer automatically and always when auto button is enabled. Seems thats how the ac is programmed in the cx5.
The only time I have seen external air and auto mode is during the colder season when it actually has to heat the cabin but in the summer it always auto switches to recirculation.
And on the topic the ac of the cx5 is a bit on the low side vs other cars I had but it does the job once the cabin gets to normal temperature.
I was speculating that its because of the location of the cabin temp sensor. Its stuck in the dash below the steering wheel if I am not mistaken.
The other item is the cabin filter. At least here in Arizona have to change it every 6mo in order to get best airflow. Too much dust here and it gets dirty quickly.
Open the windows half way and use auto. The AC system turns air recirculation during the summer automatically and always when auto button is enabled. Seems thats how the ac is programmed in the cx5.
The only time I have seen external air and auto mode is during the colder season when it actually has to heat the cabin but in the summer it always auto switches to recirculation.
And on the topic the ac of the cx5 is a bit on the low side vs other cars I had but it does the job once the cabin gets to normal temperature.
I was speculating that its because of the location of the cabin temp sensor. Its stuck in the dash below the steering wheel if I am not mistaken.
The other item is the cabin filter. At least here in Arizona have to change it every 6mo in order to get best airflow. Too much dust here and it gets dirty quickly.
My routine for cooling a hot car is to:
1) Start car, A/C on and drop windows.
2) Circle around car opening doors and hatch (lets out that load of hot air trapped in the back) and get in driver seat and remove sun shade from dash and tend to any little things. If there's a breeze through the car all the better.
3) Get out and circle around closing doors and hatch.
4) Get back in and if I feel necessary, drive a few minutes with windows down and let turbulent air carry out a bit more heat. It sounds complicated but really only takes a few minutes. My CX-5's A/C isn't the world's most powerful and needs all the help it can get to cool things down. Once cooled it maintains good on the highway but less so around town as to be expected. I haven't checked it recently, but a few times in the past show it performing to spec according to the cooling curve graph in the service manual. My long term impression is that Mazda didn't oversize the heating or cooling in this vehicle.
1) Start car, A/C on and drop windows.
2) Circle around car opening doors and hatch (lets out that load of hot air trapped in the back) and get in driver seat and remove sun shade from dash and tend to any little things. If there's a breeze through the car all the better.
3) Get out and circle around closing doors and hatch.
4) Get back in and if I feel necessary, drive a few minutes with windows down and let turbulent air carry out a bit more heat. It sounds complicated but really only takes a few minutes. My CX-5's A/C isn't the world's most powerful and needs all the help it can get to cool things down. Once cooled it maintains good on the highway but less so around town as to be expected. I haven't checked it recently, but a few times in the past show it performing to spec according to the cooling curve graph in the service manual. My long term impression is that Mazda didn't oversize the heating or cooling in this vehicle.
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- Occupied Calif.
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- 2019 CX 5 GT-R
I frequently drive through areas with outside temperatures between 105-110 in the summer months. Although I try and minimize my exposure and as I start climbing up the mountain highway to my community the temperature drops about 5 degrees for every 2000 ft of elevation. So it's still fairly hot. My A/C works just fine. I also turn on the seat cooling feature, and that makes quite a bit of difference in comfort.
But I never use the Auto feature.I typically drive around with the fan on low speed and the air flow on flow through and the outside air is fine. When I turn on the A/C I go up 1 or 2 more speeds on the fan and if it is really scorching outside I set the air flow to recirculate.
I have yet to own a vehicle that had any "Auto" features like the HVAC system, the headlights or the windshield wipers that worked the way I would set them manually. If I have to fiddle with the controls while driving, what is the point of Auto settings ?
But I never use the Auto feature.I typically drive around with the fan on low speed and the air flow on flow through and the outside air is fine. When I turn on the A/C I go up 1 or 2 more speeds on the fan and if it is really scorching outside I set the air flow to recirculate.
I have yet to own a vehicle that had any "Auto" features like the HVAC system, the headlights or the windshield wipers that worked the way I would set them manually. If I have to fiddle with the controls while driving, what is the point of Auto settings ?
I'm a bit disappointed with the aircon cooling [and heating] on a 2021 CX-5 Sig due to it's lack of oomph - was also hoping setting it to 'auto' would be sufficient, but I find I have to tweak it. In the recent hot weather, it seems to just blow out the centre vents [reasonable strong blow but not that cold even after many minutes] - reducing the temp setting just increased the fan speed (maybe the fan should get slower to reduce the volume of air the aircon has to cool & hence reduce the temp more?). Even after 15+ mins the fan speed will have reduced slightly but still set only to centre vents - I usually manually moved some air to feet vents (which is also quieter) but this then switched off auto
Is there any way to see what the car senses the inside cabin temp is i.e. what the system then uses to adjust the setting?
Is there any way to see what the car senses the inside cabin temp is i.e. what the system then uses to adjust the setting?
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- '22 X3 M40i
On really hot days I’ll spin the AC compressor faster by running the engine at higher RPMs via manual mode or selecting “sport”. After a few minutes it’s usually blowing cold enough to switch back to a regular driving mode. For reference, I live in an area that regularly hits 90’s and has very high humidity.
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- Denver, CO
I sometimes find the AC a little lacking, but that's usually when in direct sunlight and high heat for long periods and it being a black exterior and interior car.
Thanks, as a octogenarian retired Electrical Engineer (Computers) I totally agree. It's simple thermodynamics...
I live in sunny southern New Mexico (Las Cruces), and tempertures typlically run between 100 and 115 with very low humity, durning my recent trip to Katy, Texas... basically Houston, the tempertures were in the high nineties and the humity was 90%+... my 2019 CX-5 Grand Touring was cool and comfortabe and with the auto sense 'on' the fan speed went to high when we first started the car.
Very happy with my 2021 GTR where in FL. I start mine in recir and leave it there. I will crack open ~ 1/2 inch sometimes a rear window to get some fresh air in. This in Urban driving. You don't want to run hours in recir if on a long highway run because of stale air (CO2) will make you sleepy. Ed
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- CX-60 Takumi
Take it from an engineer.
A car and a building have no comparison when we talk climate, most modern buildings have HVAC, just to ensure a good indoor environment where there is not too high Co2 content, with constant recirculation in the car, Co2 can rise above tolerable levels.
