Understanding multi zone / auto climate control

[JHZR2]

Both of our Hondas have this dual zone/electric climate control system, and the hybrid has a supplemental electric heater.

But what if you DO NOT want heat? Does the "LO" setting absolutely prevent any heat (coolant based or otherwise) from going into the cabin? I've not seen it described in such terms.

I'd assume that the logic works something like this:

-LO setting = no heat input ever, but max AC operation at any interior temperature.
- if T>set point, no heat, and cycle AC to achieve temp
- if T -HI setting operates heat at full operational mode regardless of interior temperature, use of AC dependent upon user selection.

Now, using the "auto" mode and just selecting a temperature probably has more smarts, but I've not found that mode to my liking, because if the difference between the interior temperature and the set point is too high, the fan blasts more strongly than I like. Just user preference.

But is that logic sensible? Is there any reason if not in defrost mode, why heat would be used if I keep the settings on LO?

In intermediate temperatures I guess one just needs to track interior temperature vs set point if you want to avoid getting into a less efficient mode. I figure heat = efficiency loss, especially in the hybrid. And when there's a setpoint temperature as opposed to a dial with varying shades of red as the blend door opens manually is new.

Full disclosure - in all my old fashioned manual control cars, it's rare that I ever move the heat dial off full cold, ever, except during coolant maintenance, so this isn't really sacrificing to be green, rather I like the cold within reason and are not the biggest fan of these electronic systems.

 

[michaelluscher]

How do you rarely move the temp control off full cold?

You live in Jersey, and last I checked, Winter doesn't skip you?

 

[Johnny2Bad]

Is there not a temperature control?

There should be a fan control and a temperature control. You can have Lo fan without the heater on.

Plus there are other modes which are designed to control humidity, HEPA filters, etc.

 

[daves87rs]

This is why I like the old fashioned single zone ones...there are many times I just want the windows down..

Not when it can be all or nothing sometimes....

 

[JHZR2]

Originally Posted By: michaelluscher
How do you rarely move the temp control off full cold?

You live in Jersey, and last I checked, Winter doesn't skip you?


You know we have moved on as a population, from loin cloths and mass dieing due to living in caves and earthen structures

It has to be in the teens for me to use heat. A few layers and I'm good. Cold ears and hands are my only real issues, and gloves and hats fix those...

 

[JHZR2]

Originally Posted By: Johnny2Bad
Is there not a temperature control?

There should be a fan control and a temperature control. You can have Lo fan without the heater on.

Plus there are other modes which are designed to control humidity, HEPA filters, etc.


Yeah, there's fan speed, AC on/off, and temperature setting (a specific number). My thing is that the temperature setting is a specific number, and you know that the hvac control knows the interior temperature, heck, my 83 MB knew that. So if it's trying to do "too good" of a job hitting a setpoint, it actually uses energy that I'm not sure really needed to be spent.

So it's more of a thought exercise of interest to me from the perspective of optimizing efficiency as someone who really doesn't typically care for having the heat on.

In an old fashioned design where there's really just a dial that varies how far a blend door opens. Here and especially in the hybrid where there's the potential of an electric heater coming on, there's a lot more to that number that's being set by the use of the red and blue up and down buttons.

 

[Leo99]

You drive around all bundled up in your car in the winter so you won't have to use the heat?

As someone else on here wrote, that car is to serve me. I'm cranking the heat if I'm cold in the car. I think of it as free heat, the engine is heating the coolant anyways, might was well benefit from it by letting it flow through the heater core and blow it into the cabin. I'm not aware of my car having an electric heater in it, so I don't comprehend what energy it's spending that wouldn't otherwise just go to waste through the radiator.

 

[dishdude]

Every car I have had with electronic CC, setting it to LO, A/C, recirc and auto off give you vent pass through.

 

[Jetronic]

Dual zone means the driver has a seperate temperature setting from all the passengers. That's the only distinction.

the heater (using coolant to heat) uses full heat at HI, no heat at LO, and varying amounts in between depending how far you are from the setpoint and what the outside temperature is.

The electric heater could have various power outputs, but I've never seen it and doubt this. Electric heaters in non-hybrids are usually around 900 watts, I expect there's a stronger or more heating elements in a hybrid.900W in a 12v car means about 75 Amps, but there's no reason this would work on 12v only in a hybrid. Lower amperage means better chance of being controlled by PWM.

 

[eljefino]

I had a co worker who dressed for winter and ran just enough tepid hot air to keep his breath from frosting the windscreen. One may even use the dash vents instead of the defrost vents for this, with flow-through ventilation that exits out the rear doors.

I tried it. Snow doesn't melt down by the wiper rest position. When you drive during a (cold) snowstorm, it just whisks itself up over in the slipstream. No wipers, no blue juice necessary. Then when you park, you don't get an ice growth on your wiper blades.

I had a cutlass ciera I was always fighting the HVAC system. It had flow-through, to the feet, with ram-air. Even with the fan off, if I started driving in the cold, I'd get a cold breeze on my feet for a few miles before the heater warmed up. I put in a toggle switch to kill the AC that always came with defrost. On a cold, damp, 40 degree day, on a cold start, the outside of the windshield would fog from the AC running and the heat not being there yet. I selected DEF as it was the only position where ram air wasn't directly blowing on me.

/ rant

 

[Vikas]

Honda have A/C off toggle switch. That will prevent A/C from coming on. Then you can play with temperature dial to get the outside air. The A/C toggle switch is a "sticky" one across the restart. Put your temperature lever to around 60 and you won't have to worry about A/C or heat unless outside is about 40 or below.

 

[Andrew1972]

Turn the climate control off and then click the vent toggle. It shuts off AC and heat and just acts as ventilation in my 2007 MDX. Likely similar.

 

[JHZR2]

Originally Posted By: Leo99
You drive around all bundled up in your car in the winter so you won't have to use the heat?

As someone else on here wrote, that car is to serve me. I'm cranking the heat if I'm cold in the car. I think of it as free heat, the engine is heating the coolant anyways, might was well benefit from it by letting it flow through the heater core and blow it into the cabin. I'm not aware of my car having an electric heater in it, so I don't comprehend what energy it's spending that wouldn't otherwise just go to waste through the radiator.



Where exactly did I say that I drive bundled up to not use the heat?

If you would have read a bit further, you would clearly see that until it is teens or colder, I have very little need to "warm up" once out of the wind and in the cabin of my car.

Its a personal preference, and has nothing to do with anything else.

Now Im interested in it because I have a hybrid that operates differently than standard IC always on cars. But Ive never been one to crank up the heat. Nor wear that heavy of a coat. Some people like it on the colder side, Im one of them.

 

[Vikas]

are you saying automatic A/C on your two Hondas are different?

 

[Alfred_B]

In mine (not a Honda) I have temperature setting for driver, passenger and the back seat passengers. The AC is always on regardless of the temperature. If it's set to "HIGH" then the AC will still be engaged but acts as a dehumidifier.

There is an "ECO" option that turns off the AC but it causes humidity issues and will not allow the temperature to go below the ambient temperature outside. Works somewhat well in sub-freezing temperatures.

I will only turn on the "AUTO" function in very hot weather as it blows at full speed from all the applicable vents. Otherwise, the fan is set at around 4 (out of 12 speeds).

 

[JHZR2]

Originally Posted By: Vikas
are you saying automatic A/C on your two Hondas are different?


Well the hybrid certainly makes heat and circulated differently, as well as has an electric heater to augment. How do you blow consistent heat when the engine is cold and off, but you have some kWh behind your seat??

Are the algorithms different? Is suspect so; Honda says when Eco mode is enabled on the hybrid, it changes how it operates. Is the circuit board behind it different? No clue.