first off, please don't do something that is potentialy dangerus if you aren't sure what you are doing, your owners manual should tell you how to use the ignition key, and that if you turn the key back to "run" (not "start") then all of your lights, turnsignals, odometor, and everything will turn back on, but because you haven't turned it all the way to "start" the engine will not be running, unless of course you have a manual tranny, and pop the clutch.
Befor operating a car I highly recomend that you read the manual, and fully understand how it works.
Also haveing your heater/vent fan on does draw electricity, my '92 honda civic draws 11amps on the highest setting, that is around 130 watts, or about the same as what the headlights draw on their high beams. http://www.gassavers.org/showthread....lectrical+draw
as you can see, the first fan setting only draws 3 amps, or about 36 watts, you can keep the inside of your car cool by parking in the shade, if you must park in the sun then cover your windsheild with something reflective and leave your windows cracked.
I think you're doing pretty good, honestly. You're correct about not wanting to coast with engine off, as this *will* cause damage to an automatic transmission. You can, however, coast in Neutral, with the engine on, for as long as you want. I've seen folks tow cars cross-country, with the tranny in N and the motor idling along behind the RV. It's perfectly safe, as long as the transmission doesn't shift into gear, or the motor stall.....
Having the fan on high I think does reduce FE. With my scanguage I can see small jumps at idle when I turn on the fan, or my headlights. Of course the effect is not very noticeable while at speed, but every bit helps.
Wow, thanks for the feedback everyone. It's really nice to find people who care about economy and are willing to share experience.
I park on a big concrete lot with very little shade. I open the windows weather permitting and that helps. Guess I better get one of those reflective screens for the windshield.
I try to drive with the windows closed above 45 mph. That's whats got me running the fan. I have push button air conditioning, so it's real easy to turn it on and off. I'm trying to run it only to keep the cabin cool enough for comfort. I think I'll stop running the fan then the rest of the time.
I have a hilly, curvy commute along with lots of ordinary folks. Farmers, commuters, big rigs, you name it, just everyday people who use the road. My cruise control really likes to jump to another gear and I'm thinking I'd be better off to try to feather the throttle rather than plow up the hills. If I'm careful, it seems I can keep my speed most times without downshifting to another gear. Am I saving gas this way?
I've also been thinking about the amount of gas I keep in the tank. I'm pretty sure it's the 18.5 gallon capacity. Generally, I fill it up once a week. I've seen some of the discussions here go into weight savings. I only need about 4 gallons a day. Would I see a savings by only keeping what I need in the tank?
I'm thinking I'd be better off to try to feather the throttle rather than plow up the hills. If I'm careful, it seems I can keep my speed most times without downshifting to another gear. Am I saving gas this way?
I try to drive with the windows closed above 45 mph. That's whats got me running the fan.
How much difference the fan makes, depends on a number of factors: how many watts your fan draws (the more watts the bigger the drag on the engine), how efficient your alternator is (as the efficiency of your alternator declines, each watt "costs more" in terms of drag on the engine), how efficient your car otherwise is (small FE cars actually have a higher percentage of their total load from electrical sources such as the fan), etc.
So how much "conserving electricity" in a car helps, is clearly a YMMV thing. However, the people saying it makes no difference at all (and even some mechanics believe this myth), are totally wrong (even if they don't realize it). Because all electro-mechanical generators (including the "alternator" in a car) increase their mechanical drag, as you increase your power usage. So increasing electrical usage in a car, results in a measurable (and mostly predictable) increase in alternator drag on the engine, which in turn will lower your fuel economy some (in some cars the lowered FE is too small of a percentage for most people to notice, but that effect is ALWAYS there in ALL cars/trucks)!
FWIW on my CRX (a small, reasonably FE car), the electrical drag on my engine (from running the fan) actually seems to be HIGHER than the aerodynamic drag from cracking the driver window about an inch (i.e. after running several months both ways, I find I get better FE if I leave the fan off, and crack the window). So I've started routinely driving down the highway with the driver window open a crack, but with my vent fan off (the car is still set to "vent", and there still is a little air through the vent when driving, but I often now leave the fan off).
NOTE: One popular way to conserve electricity (and therefore get slightly better FE in a car, due to lower alternator drag on the engine) is to convert many of your car's lights over to energy efficient LED modules. You have to be careful which modules you get, as many of the cheaper modules are poor lighting junk (so it's clearly "buyer beware"). However, more than one of us on this forum (myself included) have done this car light conversion, and it does seem to help a little bit (for a total cost of maybe $200/car). And a (properly done) LED conversion can have other useful advantages as well, such as lights that never burn out, and brake lights that come on about 1/8th second faster than stock bulbs (which means the person behind you as about 1/8th second more reaction time to avoid running into the rear-end of your car)...