Vacuum vs. electric wiper energy use

I know that vacuum wipers are long gone, but I wonder which one uses less energy, vacuum powered wipers or electric powered wipers. Consider the case where there was no vacuum booster on the fuel pump and the wiper motor runs directly from engine vacuum. Now this would have to exert some drag on the engine. On the other hand, electric wipers require energy which creates more drag on the engine as the alternator or generator has to produce more power. Assuming that the friction of the wiper blade against the windshield is the same in either case with the same size wiper blades and the wipers are both being driven at the same number of strokes per minute, which system, vacuum or electric, would take the most energy?

Neither vacuum nor electric wipers consume a measurable amount of energy compared to the rest of the vehicle. Vacuum wipers went out for good reason – they would not work under full throttle, espically going up hill.

Vacuum has to exist for the purpose of engine control. Vacuum powered accessories simply recovers some of the lost energy, just like regenerative braking. So I don’t think there’s energy lost associated with vacuum wipers

I would think there would be no extra burden from the vacuum since it is just using a byproduct of the engine.

That sure reminds me, had those vacuum wipers on the 60 or 61 Falcon and I think on the Studebaker Lark. Step on the gas and the wipers would stop until more vacuum was available.

The things our kids will never experience.

The problem with vacuume power accessories is energy storage. You have an abundance o energy available electrically for power steering and wipers that can more easily be added as needed into the system. The present move towards electric power steering is an indication of where all this is headed as it has been over the years. With electric power, you can also add convenience features. In wipers, it includes variable speeds, intermittent wipers, rear wipers, even wipers your headlights. It’s a lot easier, safer, more reliable to run wires then vacuume and hydraulic lines.

Even with a vacuum booster on the fuel pump driving up a long incline in heavy rain resulted in driving nearly blind. I owned a 1961 Falcon and it was a pain in the rain.

My last car with vacuum wipers was a 1948 Chevy stove bolt 6, and, yes they were a pain going uphill.

‘Vacuum power - free, and worth every penny!’

The reason I asked this question was that the school bus I rode in the early 1950s had vacuum wipers. In a heavy rain, the driver would have to release the accelerator to make the wipers move. I asked him why electric wipers weren’t used. He said that the electrical system on the bus had enough problems keeping up with the load put on by the lights. In those days, the buses were on truck chassis, the electrical systems were 6 volt as opposed to 12 volt and generators were used instead of alternators. I do remember that sometimes on days where the headlights were used, some drivers after letting us off at school could not start the buses due to a run down battery. I suppose that the stop and start driving and low speeds kept the generator from adequately recharging the battery. The drivers were owner-operators of the buses and, in my district, were farmers. When the school bus was no longer suitable for passenger service, the body was removed from the chassis and a cab from a junked truck was put on the frame, and a grain bed built behind the cab on the chassis. The bus body that was removed became a chicken coop or a tool shed.
The last car I had with vacuum wipers was a 1968 AMC Javelin–bottom of the line with a 6 cylinder engine. I’ve often wondered why it was cheaper to equip the car with vacuum wipers and a dual section fuel pump than electric wipers and a single section pump.

@dagosa–the speed could be varied on the vacuum wipers depending on how far you turned the knob. Of course, these wipers also tended to vary the speed “automatically” depending on how far the accelerator was depressed. The 1948 Pontiac had an optional rear wiper and it was powered by engine vacuum. A long vacuum hose ran to the rear of the car.
My dad used a 1940 Chrysler for a year that a friend left with us while the friend was on leave for a year. That Chrysler had electric wipers. It seemed weird to me that 28 years later, my 1968 Javelin still had vacuum wipers.

Well, @dagosa–, Chrysler was ahead of most vehicles for many years. But to answer the OP’s question, Vacuum wipers used no energy.

I vividly recall being in my brother’s '54 Ford (equipped with vacuum-powered wipers), on a night of torrential rain while we were driving on a mountain road with no shoulders. To say that we were panicked from driving blind much of the time does not even come close to describing the feeling we experienced by having to keep driving in that car during those conditions.

However, one of his later cars–a '64 VW beetle–had the unique quality of having electric wipers that were totally ineffective in a heavy rain, so simply substituting electric power for vacuum power is not the total solution. Instead, it is necessary to have a properly-designed wiper system, and–luckily–all modern cars seem to have that feature.

"pain in the rain"
That sounds like something Willie Nelson should be singing.

This maybe off topic, but I wonder if pneumatic wipers, powered by air brake’s air compressor, is more efficient than electric. For some reason, those were used well into the 90s.

If we look at all the accessories on a car and decide, are we going to have multiple technology to drive them or a single, controllable, light weight, easy to install technology, the electric drive wins hands down even if other techologies may in some applications, be slightly if at all more efficient. It doesn’t matter, convenience and flexibility in operation, proven durability and manufacturing ease trumps all.

Well chunkyazian I don’t know of many cars with pneumatic/air brakes today!!
Everyone KISS electric wipers seem to do very well.

I don’t remember having problems on the cars I owned with vacuum wipers when there was a vacuum booster section on the fuel pump. These cars included a 1947 and 1955 Pontiac, a 1954 Buick and a 1965 Rambler Classic and 1968 AMC Javelin. However, my 1950 Chevrolet pickup truck which pulled the vacuum straight off the manifold without a vacuum booster on the fuel pump was terrible. However, I do think electric wipers are better.
I’ve also never replaced an electric wiper motor. However, the vacuum motor on my 1965 Rambler and my 1968 Javelin had to be replaced. The motors failed in the same week. I located a new wiper motor for the Javelin at the Rambler dealer and installed it. A few days later, the vacuum motor quit on the Rambler. I went back to the Rambler dealer and was told that someone came in two days ago and bought our last vacuum motor and I would have to wait a day. That person was me.

“The motors failed in the same week”

It sounds like AMC had elevated planned obsolescence to a high art!


Well heres a question, what was the last vehicles in the US with vacuum wipers?

I’m fairly certain that AMC holds that title.