Test #4: A/C On, Windows Up vs. A/C Off, Windows Down Cold Hard Facts: No measurable difference
I would like to see the facts of that test. I know that just about every car I have had I would burn up noticeably more in gas using the A/C than driving with the windows down.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
I would like to see the facts of that test. I know that just about every car I have had I would burn up noticeably more in gas using the A/C than driving with the windows down.
I've been hearing this tip make the rounds since the late 80's. Personally, I've never noticed much of a drop in fuel economy when using the a/c anyway. However, with newer, more efficient cars that have smaller engines that have to work harder, maybe the a/c puts more of a strain on it?
Now I imagine that if you're rolling down the highway doing 70-80 mph and you're comparing using the a/c against rolling all the windows down as far as they'll go, I guess it's possible that the a/c could be more efficient. But at 70-80 mph, I'm not going to have the windows down all the way. They're only going to be cracked a couple inches, at the most.
I just got back from the gas station, filling up my '85 Silverado, and filling up a 5 gallon container for lawn equipment. The truck sucked down $47.70 worth of $3.459 mid-grade, and by the time I put some fuel in the container, I was up to about $63-64!
The last time I personally filled this truck up was a little over a month ago. Since then, my roommate has been driving it almost exclusively. Looking at the mileage log, I see he put $20 in about 2 weeks ago, and another $10 in just last Wednesday. Overall fuel economy was pretty bad. About 10.5 mpg.
But, he's a leadfoot compared to me...I could probably nurse 12 mpg out of it that kind of driving. And even with that horrible fuel economy, I guess $77.70 every 35 days really isn't that much of a killer. Even swapping it for a car that could somehow get 42 mpg would only save about $58 per month.
And short of a hybrid or maybe a Jetta Diesel, are there any cars out there that could reasonably get 42 mpg in purely local, stop-and-go driving, where the maximum trip is less than 5 miles?
I've been hearing this tip make the rounds since the late 80's. Personally, I've never noticed much of a drop in fuel economy when using the a/c anyway.
Over the last 30 years of my driving I have always kept an eye on my mileage. Over that time I almost always drive with the windows open a/c off. Over those decades there have been several periods of intense heat that have lasted several days where I would drive with the windows up and the A/C on all the time for the duration. Each time I notice a noticeable drop in mileage.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
If you are in the market for a $30000 vehicle nearly all the hybrid autos are less than $30K. There is no such thing as a 'recovery period' for a number of reasons unless you're going to use the vehicle for business. All vehicles are just 'expense sinks'. Everyone of them just sucks up money and you get nothing from it except transportation. All you can do is add up all the expected expenses and see which one costs less over a given expected life or usage.
It mainly depends on what you want in a vehicle. A bicycle is nearly always the best choice to avoid consuming fuel.
Snake, just out of curiosity, what kind of mileage drop would you usually see?
One instance that comes to mind for me was back in 2005, when I took my 2000 Intrepid on a trip. Two friends and I went down to Florida. Had the a/c going just about the whole time, as it was really humid, and I was probably averaging 70-80 on the highway. For that whole trip, I figure we averaged about 27.5 mpg. Which for 3 people and all their luggage, a/c going the whole time, and throwing in a lot of stop-and-go local driving when we were down there, that doesn't seem too bad.
In contrast, the best mileage I ever got out of that car was about 31. That was last October, when I went up to PA for the Fall Carlisle. Just about pure highway driving going up, speed ranging from 60-70 for the most part, and no a/c. And it was just me in the car and just an overnight bag, versus three people and a trunk packed to the gills. Oh, I did have four Pontiac rally wheels in the trunk on the way back, though, so I guess that might've added around 100-120 pounds?
So comparing the two trips, my fuel economy was about 13% worse on the Florida trip. But that was a combination of factors...added weight, increased speed, a slight mix of local driving, and constant a/c use.
was an oasis of rare good weather here in new england lately. took the explorer to the gas station filling up at 3.299. after that i washed it up for the first time in many months. it still looks good and the v8 still rumbles, so when the equinox next to me at the light, tried to jump it, when the light turned green, i let the cat out of the bag a bit. it felt good. :P
2024 Ford F-150 STX, 2023 Ford Explorer ST, 91 Mustang GT vert
Snake, just out of curiosity, what kind of mileage drop would you usually see?
Well going back about 15 years there was a week where it was hot enough that I used the A/C for all but one day going to and from work. Then as now I topped off the tank on Sunday night. IIRC that week was about 8% less mileage. I like to use that as an example simply because the driving conditions were the same as when I normally drove with the A/C off. Same route, same traffic patterns, same driving style, same time of day, the only difference was using the A/C.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
The problem with the test is that neither one is an ideal solution. A/C saps energy. Turn off the AC but roll down the windows and you're creating additional drag. They should have tested both against A/C off, windows closed, and then made a recommendation.
We need to go back to the "good ole days" when cars had vents that could be opened to let it lots of fresh air and the windows needed only be down a little to let the air out to get a high speed cooling air flow. I believe a 1950 Studebaker had a scoop that could be raised in front of the windshield. A 67 Mustang had openings next to front seat occupants' feet that could be opened any amount to let in as little or as much air as the car's speed could initiate.
Not always. Some of them default to being on in all cases, and some people never notice enough to turn it off (and having to turn it off all the time can get tiresome). Most of them turn the A/C on when any amount of air is going to the windshield defroster vents, and no way to turn it off either (and some cars STILL only offer a split between that and the floor as the only split).
Plus some people just don't know what to do with a vent/recirc switch, and never have. :shades:
But todays A/C systems can vent in outside air without turning the A/C on.
Somehow though, it just doesn't seem the same. Today's a/c systems still vent it through the system, and it only comes in as fast as the fan will allow it to. And it never seems all that cool, IMO. It just can't compare to the old days when cars had those fresh air vent doors under the dash that let it in directly. Now coming through the HVAC system via the fan, that might actually be better when you're stopped in traffic, but out on the highway, the fresh air blasts through those old style direct vents with more force than any automotive fan could put out.
That, plus those vent windows, and rear windows that would roll down all the way, helped make lack of a/c more bearable in older cars. Plus, if you go back far enough, they didn't have as much insulation in them so they'd air out better, and the more upright side windows seemed to help shelter the interior from the sun better.
As for that "helicoptering" effect, my 2000 Intrepid was the first car I ever noticed it on. It only occurs if you roll down the back windows and leave the front ones up. However, after hearing it in that car, it seems like it put me more in tune with the reverberation. Nowadays, I can actually pick up on it in just about any car where the back windows don't roll all the way down. Even in my '89 Gran Fury, where they went down all but maybe an inch and a half, I could still sense it. However, the more aerodynamic the car is, the worse it seems to be.
You're right that they do--at least mine do so easily.
But there's a difference in where the air goes and how it feels. And the vents that I recall on earlier cars brought in air in great volume without having the blower fan roaring--at least when the cars were moving.
A 65 Mustang, without air conditioning, had a knob under the dash on each side that opened the vent that was in the bottom of the A-pillar. At speed that was all that was needed to feel cool because it blew on your legs and up over you.
I get better mileage with the AC on in the summer than in the winter with the AC off.
Depending on where you live, gasoline is formulated differently in different seasons. Oxygenated gas has less energy than the summer stuff, so that is one reason that fuel economy could suffer.
Cold starts take more and the transmission seems to be stiffer for about 10 miles on my car in the cold winter temps. After that the mileage seems to be up to normal on highway driving.
How much did you ever get out of your Uncle's Corolla?
The only time I actually measured fuel economy was that first time I drove it up to meet you guys last April when we went to Spring Carlisle. I got about 37.4 mpg, and that was just about pure highway driving. I topped off the fuel tank just before starting up there, and then filled it up when I got back. That was with no a/c use, and fairly mild driving. My uncle tends to keep a lot of junk in his car, but I don't think it added too much weight.
I remember driving that car up a second time. Maybe it was when we went to the Ford Nationals in June? I remember it being warmer, and using the a/c. I didn't check the fuel economy that time though.
I probably won't drive it any more, either. It's just not a good long-distance driver. I mainly did it as a test, to see what kind of fuel economy I could get out of it, and also to see if I could tolerate a car that small. While the 37.4 mpg was nice, it just wasn't worth the discomfort. Especially when the Intrepid can get 30-31 when driven the same way.
I actually find my '76 LeMans and '79 New Yorker to be better long-distance cruisers whenever I make the trip up in either of them. I get tired of the Corolla in about 10 minutes, whereas the Intrepid starts irritating me after about 45. The LeMans usually lasts me for at least an hour, and in this case I'm usually just getting fidgety, whereas the Intrepid and Corolla give me aches in my lower back and legs. And the New Yorker can usually get me all the way up there without any discomfort.
But on the downside, the NYer and LeMans only get like 15-16 mpg on that trip. :sick:
"While the 37.4 mpg was nice, it just wasn't worth the discomfort. Especially when the Intrepid can get 30-31 when driven the same way."
I'm experiencing that right now, I have a Corolla loaner while my ES300 is getting fixed (yes, Lexus cars do break! At least it's gone 120k relatively trouble-free). It's a great reminder what I'd have to give up (quiet, smooth ride, vibration free acceleration, and a roomier back seat) if I wanted to really get good mileage.
I probably could deal with something like my uncle's Corolla for the most part, since most of my driving is just local. Other than the trips up to PA for the Carlisle and other car shows, I usually don't go very far. I probably drove about 6,000 miles total over the past year, spread out over several cars. It's just that on the occasion that I'd need to go on a longer trip, I'd hate driving the car.
And another side effect of not driving a lot is that fuel economy actually becomes less important. In local driving I can get 20 mpg or so out of my Intrepid, whereas my uncle's Corolla might get 30. So where the Intrepid might use up to 50% more fuel than the Corolla, neither is really using much fuel to begin with. Even if all my driving was local, where the Intrepid got 20 mpg and the Corolla got 30, in the course of 6,000 miles per year I'd save 100 gallons. Or $400, when gas gets to $4.00 per gallon. A whopping $33 per month.
Even if all my driving was local, where the Intrepid got 20 mpg and the Corolla got 30, in the course of 6,000 miles per year I'd save 100 gallons.
I know some people that probably spend that much in propane and heating oil, letting the dogs and cats in and out of the house about every 2 hours. In looking to purchase a place I went to 1 house where they had cut a 1 sq. ft. hole thru the entire 8" thickness of the wall and had installed a 1/4" thick flap. there was quite a draft coming thru! So I can imagine they used quite a bit of extra oil.
there was quite a draft coming thru! So I can imagine they used quite a bit of extra oil.
I don't think it occurs to many people just how much they lose with a small hole during the cold weather. I live in a very well insulated home in San Diego. I had one month of $500 for propane at the new high prices. What would I be paying if it was really cold?
I get better mileage with the AC on in the summer than in the winter with the AC off.
It depends a lot on the type of driving you do. If most of your miles are on the highway at speeds above 65 mph then you will definitely get better mileage in the summer with the AC on simply because warm are is less dense than cold air, which will more than offset the hit you're taking from running the AC. If most of your mileage is city, stop and go, driving then you'd see a reduction in mileage. Wind resistance is not much of a factor at these speeds and the extra load placed on the engine to run the AC is pretty much a constant, not dependent on the speed you are going. So in slower driving a greater percentage of the total gas burned is going towards running the AC.
My house is 92 years old, not very well insulated, and pretty drafty. Over the fall and winter I did a little insulating and caulking and sealing here and there, and it seems to have helped somewhat. In the past, we tended to keep the thermostat around 72, but as soon as the furnace would turn off, it would feel cold almost immediately as the heat dispersed. So sometimes if we got cold enough, we'd move the thermostat up another notch just to make the furnace kick back on for a few minutes, but then it would just repeat the cycle, as the drafts would make it feel colder than it really was.
With the insulating I've done, we can now keep the furnace set around 68 degrees, and it feels more comfortable than it did at 72+, as there's less of a draft.
I'm not sure how much of a fuel savings I'm seeing yet, though. I have an excel spreadsheet where I keep track of oil deliveries, usage, etc, and as of 3/11/08, my last delivery, it's averaged out to about 460 gallons of oil per year. I paid $3.71 per gallon for my last delivery, so that averages out to...ouch, about $1700 per year!
the first year I was in the house (~November 2003-Oct 2004), I was only paying about $1.27 per gallon. If oil gets much more expensive (and I'm sure it will), I'm seriously considering switching to a heat pump.
Pardon my late response. This is a busy thread and I took the weekend off. :shades:
I think gigantic rims on a Prius defeats the purpose of the car. You're saying it's still more fuel efficient than most other cars, OK, but it's the least fuel-efficient Prius on the road. Least efficient among its peers.
You would think that would matter to a Prius buyer.
You don't see many Hummers with low-rolling resistance tires.
Well, as long as we are answering questions that were a bit ago I'll chime in on the mileage question on Andre's Corolla....
I once had a car that would break 40 mpg on a long trip. It was an 85 Sentra. It was slow as a slug - even with the 5 speed - but it was utterly reliable and sipped gas. Unfortunately it drowned in a noreaster back in 92.
2015 Mazda 6 Grand Touring, 2014 Mazda 3 Sport Hatchback, 1999 Mazda Miata 2004 Toyota Camry LE, 1999.
You just conjured this hilarious mental image for me: a Hummer driver "going green" and switching to those skinny hard LRR's for his H2. :-P
Just imagine how huge and empty the wheel wells would look!
Considering how huge those rubber slabbs are that H2s roll on, I wonder which would cause a larger-percentage change in mileage: the Prius driver with the 20s and 245 mm sport tires, or the H2 driver with the Prius rims and original equipment tires.
Anyway, thanks for the laugh! :-)
2014 Mini Cooper (stick shift of course), 2016 Camry hybrid, 2009 Outback Sport 5-spd (keeping the stick alive)
" If oil gets much more expensive (and I'm sure it will), I'm seriously considering switching to a heat pump. "
Heat pumps are HUGE energy savers because you don't make heat. Only move it. They use about 1/3 to 1/2 as much energy to heat a given area. They also serve as your central A/C (by running in reverse). The best heat pump setup is a geothermal (buried heat exchanger) rather than above ground, air heat exchanger. During heating season, once air temps get much below 35 degrees, your supplemental heat source has to start working too much with an air exchanger. In the cooling season, you are trying to move heat to the outside, but it's 100 degrees. By contrast, the earth stays at a fairly constant 50 degrees, so is a really efficient place for the heat exchanger.
A heat pump combined with radiant floor heat is even better than one combined with forced air because you can usually run a radiant floor thermostat at a lower temp and still be comfortable. You lose the ability for it to serve as an A/C, though, so that is one pro to a forced air system.
If you don't have enough yard space to lay out the ground loop horizonally, you can do a vertical setup where they drill a hole, similar to drilling a well, and run the ground loops vertically.
In the winter, you can use them to heat your water, too. Again, quite efficiently compared to electric or gas.
These systems are huge energy savers and I wish all builders used them as the default system on new construction. We had an air heat-exchanger heat pump once in a previous house and loved it. We investigated adding one to our current residence but couldn't because we don't have forced air and don't have radiant floors. We have a boiler with the long wall radiators and a heat pump needs more surface area than they can provide. Since it's a log home, we don't really have a decent way to cut in vents for a forced air system.
So we did the next best thing and replaced the 30 year old boiler with a high efficiency boiler. Not only does it use way less propane, but since it's a high efficiencly unit (meaning a second internal heat exchanger) the exhaust gas is only warm vs. hot so doesn't require a chimney. Only a PVC wall exhaust similar to the intake. We can now take out the chimney and also the old cold air intake vent that let cold outside air dump into the boiler closet. Now there will be way less cold air venting inward in the first place plus two less holes in the roof for future leaks. I still wish we could have done a geo-thermal heat pump, though. It will be even more important as natural gas and propane continue to become more expensive.
Heat pumps are HUGE energy savers because you don't make heat. Only move it. They use about 1/3 to 1/2 as much energy to heat a given area. They also serve as your central A/C (by running in reverse).
Back when I had my condo, I replaced its circa 1973 Rheem central air/electric furnace with a heat pump, and saw a huge drop in electric usage. With the old Rheem system, there were always a few months in the summer when the electric bill would break $200, and in the winter I think the worst I ever saw was $350!
The heat pump, which I think was a Kohler, got my summer bill down to $150 tops, and I think the worst I ever saw in the winter was $200...and even that was somewhat rare.
Having central a/c in my house would be a nice side benefit of the heat pump. I'm sure it would have to be more efficient than running the window units, not to mention giving more even cooling.
And with the way oil prices keep shooting up, I'm sure a heat pump would pay for itself pretty quickly!
Window units aren't too bad if you're only cooling certain areas of the house. For instance, if you only want 1-2 bedrooms to be cool while you're sleeping. They can remain off during the day. And you're not cooling empty rooms the rest of the time.
I use one part of the time. Saves me from cooling a big house for 24 hours, instead we only cool a small room for 8 hours.
I agree. Window air conditioners can actually save quite a bit of money and energy over central air if they are used to cool only a portion of the living space. This even though they generally have a lower SEER rating. Most window units sold today are only 10 SEER. Actually, many central air units were also only 10 SEER until the Department of Energy mandated a 13 SEER minimum, for all newly manufactured units, beginning in 2006.
But the fact remains that a central A/C system (unless it has zones), cools the entire living space rather than just one room where it is needed and that means that even an inefficient window unit may still use less overall. You can also pay extra for higher SEER rated window units, but the price difference can mean it will take a few years until you make back the extra cost.
A side benefit of a higher SEER rating is more cooling per Amp, meaning if you only want to draw a limited number of amps through one of your circuits to avoid overloading that circuit, you could get a higher BTU unit (more cooling) for the same number of amps draw if you get a higher SEER rating.
Do some asking about the underground source units. IIRC you have some room on your property. Ask reputable heating guys in the area. Stick with name brand units. Go with high SEER units but not the highest and latest and greatest (like variable speed fans and compressors). Dependability is the key.
Check with electric utility to see if they have an incentive or rebate program for switching instead of using the window units. Check into gas backup heat pumps if you have gas. Those probably cost more in the end.
Seal up your house including the wiring runs into the attic through the top plates on walls. Seal around windows--may need to remove trim to fill up.
The electric strip extra heat cuts on only below about 15 degree F. And then it's only occasionally if you're well sealed.
Note it's next to impossible to compare efficiencies based on electric bills because the hot water and cooking and lights and TV and all are in the electric along with the heat pump/AC costs. Families vary in electrical usage like our teenager taking long, long showers.
If you're using oil for heat, that will free up oil for gasoline and save you money.
Whooaaa. HUGE bill. On the coast here in NC we have what is a normal sized house ( not the $6 million kind ) and our electric bill ( the only utility ) is never over $200 for any month.
Propane was $3.28 per gallon last two fills. We only had two cool months. It is back to no heat for the last month so the Propane is just stove, water and dryer. Still a lot more than we pay for natural gas in the other house. My highest electric was during August last year. $179 for using lots of AC. Most of the time about $100. I am anxious to see how much we saved getting rid of the Spa and 56 incandescent lights. That will be on the next bill.
If you want to know where a lot of oil goes, just consider that many homes in the northeast use heating oil or propane to heat their houses. Natural gas is not available outside a narrow corridor of smaller cities and large towns. And it is still heating season here - finally getting into the 50's today.
I'm going to see a house today with a 1,000 gallon underground oil tank. The house is only about 2,000 sq.ft. and it has a couple of wood-stoves. The 1,000 gal. tank would be nice though, as I might be able to fill it in the summer, or when oil prices drop some, and not have to buy heating oil during the peak season.
I only drive about 70 miles a week and a full my tank once a month. I am 2.5 mile from work and 2 miles from wal-mart. I try to do everything in town now.
I'm going to see a house today with a 1,000 gallon underground oil tank.
Be very careful and get an engineers report on that tank. Many homes in Anchorage were put on the soil remediation list due to leaking underground oil tanks. That can add thousands to the price of the home. Some ended up going back to the bank as the cost to dig down and clean the soil was more than the home was worth.
NEW YORK (AP) -- Retail gasoline prices pulled back slightly from record levels Tuesday, but a new government forecast said gas could reach as high as $4 a gallon during the summer driving season.
In its monthly report on petroleum supplies and demand, the Energy Information Administration forecast monthly average pump prices to peak near $3.60 a gallon in June, but to rise as high as $4 a gallon at times. .
Heck, even without the high fuel costs, the commute would make me psychotic. Glad I live close to work and most of my shopping can be done within my neighborhood.
2 1/2 hours a day commuting? I bet it's more like 3 hours/day door to desk and back. No thanks. One of the few things we have some control over is commute time, some of the most stressful time of the day. Like he said, a 10 mile commute would be like he had 'gone to heaven.'
Oh I know what you mean, I would shoot myself if I had a commute like that. Currently I have a 21 mile round trip which is real nice. From walking out the door in the morning to walking in in the afternoon is only 9 hours. I love a short commute.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
Comments
Cold Hard Facts: No measurable difference
I would like to see the facts of that test. I know that just about every car I have had I would burn up noticeably more in gas using the A/C than driving with the windows down.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
I've been hearing this tip make the rounds since the late 80's. Personally, I've never noticed much of a drop in fuel economy when using the a/c anyway. However, with newer, more efficient cars that have smaller engines that have to work harder, maybe the a/c puts more of a strain on it?
Now I imagine that if you're rolling down the highway doing 70-80 mph and you're comparing using the a/c against rolling all the windows down as far as they'll go, I guess it's possible that the a/c could be more efficient. But at 70-80 mph, I'm not going to have the windows down all the way. They're only going to be cracked a couple inches, at the most.
The last time I personally filled this truck up was a little over a month ago. Since then, my roommate has been driving it almost exclusively. Looking at the mileage log, I see he put $20 in about 2 weeks ago, and another $10 in just last Wednesday. Overall fuel economy was pretty bad. About 10.5 mpg.
But, he's a leadfoot compared to me...I could probably nurse 12 mpg out of it that kind of driving. And even with that horrible fuel economy, I guess $77.70 every 35 days really isn't that much of a killer. Even swapping it for a car that could somehow get 42 mpg would only save about $58 per month.
And short of a hybrid or maybe a Jetta Diesel, are there any cars out there that could reasonably get 42 mpg in purely local, stop-and-go driving, where the maximum trip is less than 5 miles?
Over the last 30 years of my driving I have always kept an eye on my mileage. Over that time I almost always drive with the windows open a/c off. Over those decades there have been several periods of intense heat that have lasted several days where I would drive with the windows up and the A/C on all the time for the duration. Each time I notice a noticeable drop in mileage.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
If you are in the market for a $30000 vehicle nearly all the hybrid autos are less than $30K. There is no such thing as a 'recovery period' for a number of reasons unless you're going to use the vehicle for business. All vehicles are just 'expense sinks'. Everyone of them just sucks up money and you get nothing from it except transportation. All you can do is add up all the expected expenses and see which one costs less over a given expected life or usage.
It mainly depends on what you want in a vehicle. A bicycle is nearly always the best choice to avoid consuming fuel.
One instance that comes to mind for me was back in 2005, when I took my 2000 Intrepid on a trip. Two friends and I went down to Florida. Had the a/c going just about the whole time, as it was really humid, and I was probably averaging 70-80 on the highway. For that whole trip, I figure we averaged about 27.5 mpg. Which for 3 people and all their luggage, a/c going the whole time, and throwing in a lot of stop-and-go local driving when we were down there, that doesn't seem too bad.
In contrast, the best mileage I ever got out of that car was about 31. That was last October, when I went up to PA for the Fall Carlisle. Just about pure highway driving going up, speed ranging from 60-70 for the most part, and no a/c. And it was just me in the car and just an overnight bag, versus three people and a trunk packed to the gills. Oh, I did have four Pontiac rally wheels in the trunk on the way back, though, so I guess that might've added around 100-120 pounds?
So comparing the two trips, my fuel economy was about 13% worse on the Florida trip. But that was a combination of factors...added weight, increased speed, a slight mix of local driving, and constant a/c use.
Well going back about 15 years there was a week where it was hot enough that I used the A/C for all but one day going to and from work. Then as now I topped off the tank on Sunday night. IIRC that week was about 8% less mileage. I like to use that as an example simply because the driving conditions were the same as when I normally drove with the A/C off. Same route, same traffic patterns, same driving style, same time of day, the only difference was using the A/C.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
Do that here in Boise in the summer and what you save on gas will cost you in ER bills as you melt with heat prostration.
2014 Malibu 2LT, 2015 Cruze 2LT,
Nowadays you crack the windows and the helicopter noise busts your eardrums.
2014 Malibu 2LT, 2015 Cruze 2LT,
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D
Plus some people just don't know what to do with a vent/recirc switch, and never have. :shades:
Somehow though, it just doesn't seem the same. Today's a/c systems still vent it through the system, and it only comes in as fast as the fan will allow it to. And it never seems all that cool, IMO. It just can't compare to the old days when cars had those fresh air vent doors under the dash that let it in directly. Now coming through the HVAC system via the fan, that might actually be better when you're stopped in traffic, but out on the highway, the fresh air blasts through those old style direct vents with more force than any automotive fan could put out.
That, plus those vent windows, and rear windows that would roll down all the way, helped make lack of a/c more bearable in older cars. Plus, if you go back far enough, they didn't have as much insulation in them so they'd air out better, and the more upright side windows seemed to help shelter the interior from the sun better.
As for that "helicoptering" effect, my 2000 Intrepid was the first car I ever noticed it on. It only occurs if you roll down the back windows and leave the front ones up. However, after hearing it in that car, it seems like it put me more in tune with the reverberation. Nowadays, I can actually pick up on it in just about any car where the back windows don't roll all the way down. Even in my '89 Gran Fury, where they went down all but maybe an inch and a half, I could still sense it. However, the more aerodynamic the car is, the worse it seems to be.
But there's a difference in where the air goes and how it feels. And the vents that I recall on earlier cars brought in air in great volume without having the blower fan roaring--at least when the cars were moving.
A 65 Mustang, without air conditioning, had a knob under the dash on each side that opened the vent that was in the bottom of the A-pillar. At speed that was all that was needed to feel cool because it blew on your legs and up over you.
2014 Malibu 2LT, 2015 Cruze 2LT,
Depending on where you live, gasoline is formulated differently in different seasons. Oxygenated gas has less energy than the summer stuff, so that is one reason that fuel economy could suffer.
2014 Malibu 2LT, 2015 Cruze 2LT,
The only time I actually measured fuel economy was that first time I drove it up to meet you guys last April when we went to Spring Carlisle. I got about 37.4 mpg, and that was just about pure highway driving. I topped off the fuel tank just before starting up there, and then filled it up when I got back. That was with no a/c use, and fairly mild driving. My uncle tends to keep a lot of junk in his car, but I don't think it added too much weight.
I remember driving that car up a second time. Maybe it was when we went to the Ford Nationals in June? I remember it being warmer, and using the a/c. I didn't check the fuel economy that time though.
I probably won't drive it any more, either. It's just not a good long-distance driver. I mainly did it as a test, to see what kind of fuel economy I could get out of it, and also to see if I could tolerate a car that small. While the 37.4 mpg was nice, it just wasn't worth the discomfort. Especially when the Intrepid can get 30-31 when driven the same way.
I actually find my '76 LeMans and '79 New Yorker to be better long-distance cruisers whenever I make the trip up in either of them. I get tired of the Corolla in about 10 minutes, whereas the Intrepid starts irritating me after about 45. The LeMans usually lasts me for at least an hour, and in this case I'm usually just getting fidgety, whereas the Intrepid and Corolla give me aches in my lower back and legs. And the New Yorker can usually get me all the way up there without any discomfort.
But on the downside, the NYer and LeMans only get like 15-16 mpg on that trip. :sick:
I'm experiencing that right now, I have a Corolla loaner while my ES300 is getting fixed (yes, Lexus cars do break! At least it's gone 120k relatively trouble-free). It's a great reminder what I'd have to give up (quiet, smooth ride, vibration free acceleration, and a roomier back seat) if I wanted to really get good mileage.
And another side effect of not driving a lot is that fuel economy actually becomes less important. In local driving I can get 20 mpg or so out of my Intrepid, whereas my uncle's Corolla might get 30. So where the Intrepid might use up to 50% more fuel than the Corolla, neither is really using much fuel to begin with. Even if all my driving was local, where the Intrepid got 20 mpg and the Corolla got 30, in the course of 6,000 miles per year I'd save 100 gallons. Or $400, when gas gets to $4.00 per gallon. A whopping $33 per month.
I know some people that probably spend that much in propane and heating oil, letting the dogs and cats in and out of the house about every 2 hours. In looking to purchase a place I went to 1 house where they had cut a 1 sq. ft. hole thru the entire 8" thickness of the wall and had installed a 1/4" thick flap. there was quite a draft coming thru! So I can imagine they used quite a bit of extra oil.
I don't think it occurs to many people just how much they lose with a small hole during the cold weather. I live in a very well insulated home in San Diego. I had one month of $500 for propane at the new high prices. What would I be paying if it was really cold?
It depends a lot on the type of driving you do. If most of your miles are on the highway at speeds above 65 mph then you will definitely get better mileage in the summer with the AC on simply because warm are is less dense than cold air, which will more than offset the hit you're taking from running the AC. If most of your mileage is city, stop and go, driving then you'd see a reduction in mileage. Wind resistance is not much of a factor at these speeds and the extra load placed on the engine to run the AC is pretty much a constant, not dependent on the speed you are going. So in slower driving a greater percentage of the total gas burned is going towards running the AC.
With the insulating I've done, we can now keep the furnace set around 68 degrees, and it feels more comfortable than it did at 72+, as there's less of a draft.
I'm not sure how much of a fuel savings I'm seeing yet, though. I have an excel spreadsheet where I keep track of oil deliveries, usage, etc, and as of 3/11/08, my last delivery, it's averaged out to about 460 gallons of oil per year. I paid $3.71 per gallon for my last delivery, so that averages out to...ouch, about $1700 per year!
the first year I was in the house (~November 2003-Oct 2004), I was only paying about $1.27 per gallon. If oil gets much more expensive (and I'm sure it will), I'm seriously considering switching to a heat pump.
I think gigantic rims on a Prius defeats the purpose of the car. You're saying it's still more fuel efficient than most other cars, OK, but it's the least fuel-efficient Prius on the road. Least efficient among its peers.
You would think that would matter to a Prius buyer.
You don't see many Hummers with low-rolling resistance tires.
When I calculated a seasonal average, I found my peak MPG was in the fall and spring. Summer was about 1 mpg lower. Winter was about 2 mpg lower.
This was for a trip car that was not used for commuting, so the type of driving was fairly consistent.
I once had a car that would break 40 mpg on a long trip. It was an 85 Sentra. It was slow as a slug - even with the 5 speed - but it was utterly reliable and sipped gas. Unfortunately it drowned in a noreaster back in 92.
87 octane gas was $3.29.
Diesel was $4.19! 90 cents more per gallon. :surprise:
No wonder indy truckers are protesting.
Just imagine how huge and empty the wheel wells would look!
Considering how huge those rubber slabbs are that H2s roll on, I wonder which would cause a larger-percentage change in mileage: the Prius driver with the 20s and 245 mm sport tires, or the H2 driver with the Prius rims and original equipment tires.
Anyway, thanks for the laugh! :-)
2014 Mini Cooper (stick shift of course), 2016 Camry hybrid, 2009 Outback Sport 5-spd (keeping the stick alive)
Heat pumps are HUGE energy savers because you don't make heat. Only move it. They use about 1/3 to 1/2 as much energy to heat a given area. They also serve as your central A/C (by running in reverse). The best heat pump setup is a geothermal (buried heat exchanger) rather than above ground, air heat exchanger. During heating season, once air temps get much below 35 degrees, your supplemental heat source has to start working too much with an air exchanger. In the cooling season, you are trying to move heat to the outside, but it's 100 degrees. By contrast, the earth stays at a fairly constant 50 degrees, so is a really efficient place for the heat exchanger.
A heat pump combined with radiant floor heat is even better than one combined with forced air because you can usually run a radiant floor thermostat at a lower temp and still be comfortable. You lose the ability for it to serve as an A/C, though, so that is one pro to a forced air system.
If you don't have enough yard space to lay out the ground loop horizonally, you can do a vertical setup where they drill a hole, similar to drilling a well, and run the ground loops vertically.
In the winter, you can use them to heat your water, too. Again, quite efficiently compared to electric or gas.
These systems are huge energy savers and I wish all builders used them as the default system on new construction. We had an air heat-exchanger heat pump once in a previous house and loved it. We investigated adding one to our current residence but couldn't because we don't have forced air and don't have radiant floors. We have a boiler with the long wall radiators and a heat pump needs more surface area than they can provide. Since it's a log home, we don't really have a decent way to cut in vents for a forced air system.
So we did the next best thing and replaced the 30 year old boiler with a high efficiency boiler. Not only does it use way less propane, but since it's a high efficiencly unit (meaning a second internal heat exchanger) the exhaust gas is only warm vs. hot so doesn't require a chimney. Only a PVC wall exhaust similar to the intake. We can now take out the chimney and also the old cold air intake vent that let cold outside air dump into the boiler closet. Now there will be way less cold air venting inward in the first place plus two less holes in the roof for future leaks. I still wish we could have done a geo-thermal heat pump, though. It will be even more important as natural gas and propane continue to become more expensive.
Back when I had my condo, I replaced its circa 1973 Rheem central air/electric furnace with a heat pump, and saw a huge drop in electric usage. With the old Rheem system, there were always a few months in the summer when the electric bill would break $200, and in the winter I think the worst I ever saw was $350!
The heat pump, which I think was a Kohler, got my summer bill down to $150 tops, and I think the worst I ever saw in the winter was $200...and even that was somewhat rare.
Having central a/c in my house would be a nice side benefit of the heat pump. I'm sure it would have to be more efficient than running the window units, not to mention giving more even cooling.
And with the way oil prices keep shooting up, I'm sure a heat pump would pay for itself pretty quickly!
I use one part of the time. Saves me from cooling a big house for 24 hours, instead we only cool a small room for 8 hours.
But the fact remains that a central A/C system (unless it has zones), cools the entire living space rather than just one room where it is needed and that means that even an inefficient window unit may still use less overall. You can also pay extra for higher SEER rated window units, but the price difference can mean it will take a few years until you make back the extra cost.
A side benefit of a higher SEER rating is more cooling per Amp, meaning if you only want to draw a limited number of amps through one of your circuits to avoid overloading that circuit, you could get a higher BTU unit (more cooling) for the same number of amps draw if you get a higher SEER rating.
Check with electric utility to see if they have an incentive or rebate program for switching instead of using the window units. Check into gas backup heat pumps if you have gas. Those probably cost more in the end.
Seal up your house including the wiring runs into the attic through the top plates on walls. Seal around windows--may need to remove trim to fill up.
The electric strip extra heat cuts on only below about 15 degree F. And then it's only occasionally if you're well sealed.
Note it's next to impossible to compare efficiencies based on electric bills because the hot water and cooking and lights and TV and all are in the electric along with the heat pump/AC costs. Families vary in electrical usage like our teenager taking long, long showers.
If you're using oil for heat, that will free up oil for gasoline and save you money.
2014 Malibu 2LT, 2015 Cruze 2LT,
I'm going to see a house today with a 1,000 gallon underground oil tank. The house is only about 2,000 sq.ft. and it has a couple of wood-stoves. The 1,000 gal. tank would be nice though, as I might be able to fill it in the summer, or when oil prices drop some, and not have to buy heating oil during the peak season.
work and 2 miles from wal-mart. I try to do everything in town now.
Be very careful and get an engineers report on that tank. Many homes in Anchorage were put on the soil remediation list due to leaking underground oil tanks. That can add thousands to the price of the home. Some ended up going back to the bank as the cost to dig down and clean the soil was more than the home was worth.
In its monthly report on petroleum supplies and demand, the Energy Information Administration forecast monthly average pump prices to peak near $3.60 a gallon in June, but to rise as high as $4 a gallon at times.
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From the Philadelphia newspaper:
http://www.philly.com/philly/hp/news_update/20080409_Long_commutes__gas_prices_c- rimping_American_Dream.html
Heck, even without the high fuel costs, the commute would make me psychotic. Glad I live close to work and most of my shopping can be done within my neighborhood.
2011 Hyundai Sonata, 2014 BMW 428i convertible, 2015 Honda CTX700D