Climate Control (Heat) Causes Loss of MPG?

[Ill4Runner]

I know running my A/C will cause poor MPG, does running heat using the Climate Control have the same results?

My MPG has gone down since I started running heat this winter in my 4Runner. Just curious because I don't have this problem with my 90 22RE.

 

[icantsee]

 

[Pound]

I always thought it wouldn

 

[Snookster]

I always thought it wouldn

 

[Mr. Dabadina]

I always thought that only the a/c effected the MPG. Maybe something else such as cold air, low tire pressure, getting close to an oil change, or a combination of those. Or maybe your foot got a little heavier.

 

[Ill4Runner]

I was close to an oil change and just had that taken care of on Wednesday. Norm for me is 230-240 per tank with the 33's and I'm around 210 miles lately. I'll see what the mileage is after the next full tank.

I've had the 4Runner for two years now going on my third winter and this is the first time I've noticed a loss.

 

[JustAnotherT4R]

take wind into factor?

heat is drawn from hot coolent that is running throught the heater core inside the truck. which uses a fan to force it out into the cabin.

A/C needs a belt to run the A/C compressor.

so heat doesnt really affect gas.

 

[p nut]

I think this is what is happening. First, running the heater will not affect your MPG (at least nothing significant. i.e. less than .01mpg). And the MPG drop you're noticing is not coming from the heater, but the winter gas (higher ethynol content for cleaner burn). You just *THINK* it's your heater since you only run your heater during the winter time. I notice about 1-2MPG drop every winter, because of this.

BTW: PLEASE calculate MPG's, not miles per tank. Miles per tank really has no significant value, since there are so many variables.

 

[drmorbius]

I know running my A/C will cause poor MPG, does running heat using the Climate Control have the same results?

My MPG has gone down since I started running heat this winter in my 4Runner. Just curious because I don't have this problem with my 90 22RE.

Climate control will use the a/c to maintain the temperature. This means if the heater gets the air past the set temperature it will turn on the a/c to bring it back down and vice versa.

 

[JustAnotherT4R]

what about them injection clear? will that help?

 

[Pound]

I would buy the ethanol answer, as well as tire pressure, which would decrease with cold temps. And if you are doing a bunch of short drives, it will not give the tire time to heat up, to increase the tire pressure again.

Lower outside temps going through the intake would help, if anything, due to denser air.

 

[techno]

Running anything electrical will reduce the mpg, but most of the time the value is too small to be really noticable. For example, daytime running lights (on average over all vehicle brands) increases fuel consumption by about 3%. Consider the power usage of headlights compared to other things and you'll see just how small the effects can be.
If climate control is running then it it using electricity to control the amount of heat coming in (opening and closing valves in the coolant pipes), so yes it will have an influence, albeit quite small on mpgs. Also remember that if the vents are set to direct air flow to the windshield or the windshield/feet, then the a/c will always come on if the fan is on, regardless of if the a/c button is on or off.

 

[Snookster]

Also remember that if the vents are set to direct air flow to the windshield or the windshield/feet, then the a/c will always come on if the fan is on, regardless of if the a/c button is on or off. [/B]

seriously? does this only apply to vehicles with climate control?

 

[techno]

All models, and not just Toyotas. The reason is air directed to the windshield is primarily for de-fogging. Fog on the glass is moisture. Air from a/c is very dry so the air absorbs the moisture from the glass. When you use a/c with heat, you get moisture aborbtion and evaporation, hence quick defogging.

 

[Pound]

learn something everyday...

 

[gapboi210]

I also heard the reason for the compressor running on defrost is to keep the oil in the system moving to keep seals from drying up.

 

[pat161]

I have heard both of those reasons for the a/c to work with defrost, and they both make sense to me. The windsheild does clear quicker w/ the a/c and it is good to run it periodically to keep things lubed.

On a side note for anyone with manual heater controls there is a hidden function that Toyota tries to trick us out of here in the US, not sure about Canada. Apparently everywhere else there is another setting beyond defrost that will not run the a/c w/ defrost. The function is there on every 3rd gen w/ the rotary dials. All you need to do is remove the dial for the function, ie where it blows. On the dash side there is a small plastic tab that stops the dial at defrost. If you shave that tab off your dial will go one position further and run defrost with no a/c. You can try it just by removing the dial and spinning the stalk, you will see the a/c does not come on. I like this in snow and ice storms when you need to run the defrost full blast to keep the windsheild from freezing, it helps cut down on the double mpg hit of a/c and 4wd.