TV Aircon

I am wondering how the air con affects the mileage on my TV. I always use it as it stops the windows steaming up and keeps the dog cool. I am led to believe that it can be as little as 2% up to 20%. at 2% it is obviously not worth worrying about but 20% I could up my mileage over 3 miles per gallon. What are your views,
Sean

I read about this a few years ago. With the A/C off, you'd have your windows open. The wind coming in the windows will meet with resistance when it hits the back window (even with the little sliding window open). Even though the mileage might be better with the A/C off rather than on, the wind resistance might make it negligible. At least that's my kind of rationing for keeping the A/C comfortably on.

Tater

Scruffy and Tater wrote:I read about this a few years ago. With the A/C off, you'd have your windows open. The wind coming in the windows will meet with resistance when it hits the back window (even with the little sliding window open). Even though the mileage might be better with the A/C off rather than on, the wind resistance might make it negligible. At least that's my kind of rationing for keeping the A/C comfortably on.

Tater

One of the guys in the Mustang club I used to run around with actually tested this. On his particular generation of Mustang it was less fuel efficient with the windows open. The shape on the 99-04 Mustang really funnels air into the back seat and almost acts like a drag chute.

It all depends on the shape and aerodynamics of the vehicle. An F-350 is already not an aerodynamic shape, so the windows open may not make a difference. Only one way to find out for sure, road test. That is, unless Scruffy can build a wind tunnel in the back yard for aerodynamic testing.

I've run both ways Sean,and I really can't tell that much difference.

Mopar_Earl wrote:I've read were running the a/c uses less fuel than with windows down. I myself would rather be comfy even if it used more fuel.



Earl

Right on Earl. More and more it's about being comfy.

Well, here we are, snug in our house in southern NH waiting for a foot of snow. April 1st ..... go figger!

Scruffy says we have enough wind in TX, we don't need a wind tunnel.

Besides, he doesn't have time, we're starting to re-cover our patio. Old cover was wooden lattice work (not the premade stuff, all done with 2x6s), and it didn't have a slope to it - provided nice shade, but we couldn't sit out there when it rained. So we took it down. Our new cover will have polycarbonate sheeting on the top, and we'll screen it all in. Gonna be nice..... gonna be a lot of work.

Mike, sorry you're getting more snow. When we lived in Chicago, we got snow in mid-April occasionally..... like 50 years ago when we were trudging through several inches of the white stuff looking for what would be our first apartment.

Tater

Why invite the bugs in. Use the A/C. I wish that my truck had the air filter for the A/C like the new cars do.

I am lucky that the temps never seem to get very high over here, so the air con could be a luxury I could do without if it was using 20% of my fuel. I am not a tight wad but the cost of fuel at the moment is a big issue at the moment.
Sean

Scruffy and Tater wrote:I read about this a few years ago. With the A/C off, you'd have your windows open. The wind coming in the windows will meet with resistance when it hits the back window (even with the little sliding window open). Even though the mileage might be better with the A/C off rather than on, the wind resistance might make it negligible. At least that's my kind of rationing for keeping the A/C comfortably on.

Tater

Scruffy and Tater are right. The other variables are
1. Speed at which windows are left down, causes more drag at higher speeds.
2. Size of engine counts. An A/C when on, uses about 10 hp to run. Ten hp is nothing to a 400 hp engine, but it is considerable to a 100 hp engine.

Maxtor wrote: but it is considerable to a 100 hp engine.

You must be talking about a FORD!!!

Maxtor wrote:

2. Size of engine counts. An A/C when on, uses about 10 hp to run. Ten hp is nothing to a 400 hp engine, but it is considerable to a 100 hp engine.

Right on Bro!

It will make a difference on a little 4 banger or small engine. I seriously doubt these torque monster diesels will even notice the compressor kicking in and out.

Sean wrote:I am wondering how the air con affects the mileage on my TV. I always use it as it stops the windows steaming up and keeps the dog cool. I am led to believe that it can be as little as 2% up to 20%. at 2% it is obviously not worth worrying about but 20% I could up my mileage over 3 miles per gallon. What are your views,
Sean

This Topic sounds like it would be a good project for the "Myth Busters".

Frank wrote:

Sean wrote:I am wondering how the air con affects the mileage on my TV. I always use it as it stops the windows steaming up and keeps the dog cool. I am led to believe that it can be as little as 2% up to 20%. at 2% it is obviously not worth worrying about but 20% I could up my mileage over 3 miles per gallon. What are your views,
Sean

This Topic sounds like it would be a good project for the "Myth Busters".

Done

Windows down vs. air conditioning
"Urban puzzle": it is more efficient, on a hot day, to run with the A/C on and windows up than to run with windows down (b/c of increasing car's drag).

Computer-based mpg measurements: * 11.7/11.8 with A/C on and windows up * 11.7/11.8 with A/C off and windows up * 11.3 with A/C off and windows down

So, according to the computer, it's better to use A/C with windows up.

This was too quick and easy for TV, so they decided to stage a seven hour marathon, race-til-you're-empty duel, with Jamie driving an SUV with A/C on and Adam driving an SUV with windows down. Though, once the safety inspector intervened, it was no longer a seven-hour marathon, it was a bit slower (45mph instead of 55mph), and a lot shorter (only 5 gallons each).

Jamie's A/C car ran out of gas first -- Adam's windows down SUV ran for another 30 laps -- completely contradicting the computer mpg estimate. Computer estimate based on air flow into the engine, so it would appear that it is unable to properly model the difference between A/C and windows down.

Mythbusted