HomeLatest ThreadsGreatest ThreadsForums & GroupsMy SubscriptionsMy Posts
DU Home » Latest Threads » Forums & Groups » Topics » Environment & Energy » Frugal and Energy Efficient Living (Group) » An MPG tip for your car: ...

Thu Jan 9, 2014, 11:12 PM

 

An MPG tip for your car: Use defrost sparingly.

The "defrost" setting on your car works well to quickly defrost your windshield by "reverse cycling" your A.C. compressor to provide warm dry air to clear condensation, but leaving it on (either for defrost or heat) means you are giving up 2-4 mpg because you are using the A.C.

Try using the "vent" settings, adjusting the heat as necessary, after the windshield is clear. This employs only the fan and the heater core, not the A.C. Check your owner's manual to see how your settings work. If unsure, open the hood of your running engine while the heat or defrosy is on and see if your A.C. is cycling on -- a pulley clutch will be click & start spinning, stop, then resume. This means you are using the compre$$or!

Another wasteful, polluting and unnecessary practice: Letting your car idle to warm up. God! this is awful. Start your car, put it into gear, and start driving slowly without revving. Use your A.C. defrost at this time, then go to vent. Your car will warm up faster & use less gas, & suffer less wear. And you won't pollute as much. Damned urban legend was dead by the 1950s. I've driven cars 50+ yrs old immediately after starting on cold days without problems.

10 replies, 19568 views

Reply to this thread

Back to top Alert abuse

Always highlight: 10 newest replies | Replies posted after I mark a forum
Replies to this discussion thread
Arrow 10 replies Author Time Post
Reply An MPG tip for your car: Use defrost sparingly. (Original post)
Eleanors38 Jan 2014 OP
Curmudgeoness Jan 2014 #1
Eleanors38 Jan 2014 #2
laundry_queen Jan 2014 #3
Eleanors38 Jan 2014 #4
ConcernedCanuk Jan 2014 #5
laundry_queen Jan 2014 #8
ConcernedCanuk Jan 2014 #9
laundry_queen Jan 2014 #10
arachadillo Jan 2014 #6
Eleanors38 Jan 2014 #7

Response to Eleanors38 (Original post)

Fri Jan 10, 2014, 09:18 PM

1. Thanks. Great suggestions.

I was already aware of the "defrost" setting using the a/c. I have only used that setting a few times in my life when the open fresh air vents and heat have not worked....usually conditions are very damp and just warming up from a freeze when nothing else works.

I also do not leave the car idle before I start driving, and I also have not had problems. The only time that I will let it idle for less than a minute is when the temps are very cold (like this past week in the minus digits) and I just want to make sure that the fluids are all warmed enough to flow. I don't let it idle just because I am too impatient to wait, but I agree with you, I don't have problems.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to Curmudgeoness (Reply #1)

Fri Jan 10, 2014, 09:46 PM

2. Your welcome. A lot of folks don't realize that your

 

A.C. Can only cool 22-24 below ambient temp, and running it up to max only runs the comp all the time. One should find the point of max temp differential, then cut back the cooling some to allow the comp to cycle off. This allows not only better mpg, but lets the A.C. to cool itself off and to extend its life.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to Eleanors38 (Original post)

Sat Jan 11, 2014, 03:27 AM

3. Mine's manual

maybe Canadian cars are built differently because we use defrost so darn much? but I'm pretty sure my defrost does not use a/c (I can tell, my engine immediately loses power when I turn on a/c in the summer). It CAN if I want it too, there's a separate a/c on/off button, but I don't because there's no point - it's a dry climate.

I generally burn a lot less fuel in the winter than in the summer because I don't use a/c in the winter, as long as I don't idle but really, when it's -40 I have to let it warm up just to be able to turn the wheel. Also, if it's too cold my sliding doors don't work, the sensors go all crazy and think my door is always open, then I get to hear dingdingding as I drive. Stupid van. I do try to keep idling to a minimum though, but where I live it's just unavoidable at times. To make up for it, I don't drive unless I absolutely have to. People here go pick up their kids all the time when it's a 10 min walk, even when it's not cold. Not me, I'm mean mommy. My kids walk.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to laundry_queen (Reply #3)

Sat Jan 11, 2014, 08:49 AM

4. My old cars didn't even have AC; made my choices easy.

 

Today's modern EFI and better emission systems make it much easier to start up and go.

We rarely had to walk to & fro school since our folks had a real fear of the highway it was on.

One of my work panel trucks had a lower radiator hose cut in half to accomodate a metal heat element. A lamp cord led from it so you could plug it in! It had a nice bed-like frame on top and oar clips. Damned thing lived a former life in Minnesota. Didn't need the coolant warmer, but I had a jon boat in Texas!

Reply to this post

Back to top Alert abuse Link here Permalink


Response to laundry_queen (Reply #3)

Sun Jan 19, 2014, 03:08 AM

5. Block heater saves $$

 

.
.
.

Think about it - 2-3 hours on a block heater costs 30 cents maybe? (most block heaters use less than 1/2 kw per hour).

And car warmers - 1000 watt car warmer for 1 hour - maybe 20 cents of hydro?

You can use timers if on a regular schedule, or just go plug them in a few hours before a planned trip.

It took me a decade or two to realize it was MUCH cheaper to use hydro instead of gas to get the car comfy.

My engine, and my butt are happier

CC

Reply to this post

Back to top Alert abuse Link here Permalink


Response to ConcernedCanuk (Reply #5)

Mon Jan 20, 2014, 11:43 AM

8. Did not know that

I'll have to let my dad know...when I was living with my parents last year (while my duplex was being built and behind schedule) my dad wouldn't let me keep my van plugged in overnight (no timer) because he was concerned about his hydro bill...he plugged it in when he went to work, which meant only an hour before I had to go to school. He cited the high cost of electricity. Well, my battery ended up dead after a long cold snap and he bought me a new battery for Christmas, LOL, so it probably cost him more in the end. Now that I'm in my own house, I keep it plugged in if it gets even a little bit cold and it fires up much better. I may need to look into one of those car warmers. I actually leave it plugged in overnight. I find 3 hours to not be long enough when it gets down to the -25 to -35 range. When I keep it plugged in, I have no issues at all. My electricity bill last month, including Christmas and plugging in the van was lower than in summer when I run a window a/c by half. So, gonna keep plugging in the car! lol.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to laundry_queen (Reply #8)

Tue Jan 21, 2014, 12:51 PM

9. There are also battery warmers - look like them decorative toaster covers some use.

 

.
.
.

umm, no - I've never actually seen a battery warmer with flowers on it - but I think you get it

A battery below freezing has only about half it's cranking power - batteries do not like the cold.

Sorta like a tiny electric blanket for your battery. Wraps around the sides, not over the top(connections).

Car maintenance is expensive (as a retired auto and truck mechanic I can vouch for this).

Baby your vehicle - it will save you more than you can even imagine.

Those that say you can just "start and go" do not understand the theory of the mechanics of cars. Engines, transmissions and so on are designed to work at a certain temperatures - freezing ain't it, so warming up the vehicle, even if you have to use gasoline, is cheaper in the long run than "start and go".

CC

ps: link for a 900 watt interior car warmer > > http://www.canadiantire.ca/en/pdp/little-buddy-110v-car-warmer-0303405p.html#.Ut6y3_Qo5w0

Reply to this post

Back to top Alert abuse Link here Permalink


Response to ConcernedCanuk (Reply #9)

Tue Jan 21, 2014, 02:32 PM

10. Now that I see it, I think my mom had one when we were little

She got tired of warming up the car by running it for so long every morning before she took my brother and I to daycare so she made my dad buy one. Yeah, it worked pretty good.

I think I would like to see a battery warmer with flowers on it, LOL.

I do baby my vehicle quite a bit. I have to right now because I cannot afford a break down or a new vehicle. Plus, I happen to love my vehicle apart from some quirks (minivan w/power doors that don't work in -20 or colder) and it only has 70,000 kms even though it's 8 yrs old. They don't make a vehicle that's not an SUV with everything my van has anymore, so I have to make it last until my kids are a bit older and can drive themselves. I bet that heater would help with the power door problem. Hmm. I'll have to think about it.

Reply to this post

Back to top Alert abuse Link here Permalink


Response to Eleanors38 (Original post)

Sun Jan 19, 2014, 11:06 AM

6. good idea

never thought of that, good job

Reply to this post

Back to top Alert abuse Link here Permalink


Response to arachadillo (Reply #6)

Mon Jan 20, 2014, 06:18 AM

7. Thanks. Another benefit of using non-AC/hot coolant heat

 

I forgot to mention: Your heater "core," the small radiator-type unit forced-air passes through, will have its life extended by frequent circulation or flushing through it (engine waterpump); otherwise, the coolant & other materials remains stagnant in it resulting in corrosion, then leaks.

My old '63 Chevy Nova's heater core lasted for 28 yrs: the design had engine coolant ALWAYS running through it, and you controlled temp by moving via cable control a trapdoor panel that allowed more or less outside air to mingle with the hot air; when off, the panel directed all the hot air outside! Primitive, but effective.

Reply to this post

Back to top Alert abuse Link here Permalink

Reply to this thread