You step into a small metal room, press a button, and sixty seconds later you are 400 meters above the street. The room never tilts, never shakes, never makes you feel the speed. Something is pulling you up through a vertical concrete shaft at 10 meters per second, and you have no idea what it is. The answer is stranger than a powerful motor. It is a block of concrete you will never see.
An elevator does not haul you up with brute force. A hidden counterweight on the other side of the cable does most of the lifting. The motor only handles the leftover imbalance.
Most people picture an elevator the way they picture a bucket on a rope: a motor at the top winds a cable and pulls you straight up against gravity. That picture demands an enormously powerful motor. A loaded elevator car weighs 5,000 to 6,000 kilograms. Hauling that weight up 100 floors would require hundreds of kilowatts of continuous power and cables thick enough to anchor a ship. Yet the motor in most elevator machine rooms is surprisingly small, rated at 15 to 30 kilowatts for a standard building. How does a motor that could not power a large boat engine lift a car full of people up a skyscraper?
The trick is the counterweight. On the opposite end of the cable from the elevator car sits a stack of concrete and steel blocks, riding its own set of guide rails inside the same shaft. This counterweight is carefully calibrated to weigh exactly as much as the empty car plus 40 to 50 percent of the maximum passenger load. When the car goes up, the counterweight goes down. When the car goes down, the counterweight goes up. Gravity pulls on both sides equally (or nearly so), and the motor only has to overcome the difference between the two.
The cable connects car to counterweight by looping over a grooved steel pulley at the top of the shaft called a sheave. The motor turns this sheave, and the grooves grip the cables through friction alone. The cables are not bolted or welded to the sheave; they sit in precisely machined grooves that provide just enough traction to move the car without slipping. This is why the system is called a traction elevator.
Here is the counterintuitive part: at roughly 40 percent of maximum passenger capacity, the car and counterweight are perfectly balanced. The motor does almost zero net work. It just nudges the system past the friction in the bearings and guide rails. Load the car beyond 40 percent and the car side becomes heavier; the motor works harder to lift it. But empty the car completely, and the counterweight side becomes heavier; the motor now has to work to hold the counterweight back as it descends. The system is never truly idle; it is always managing an imbalance. But that imbalance is always a fraction of the total weight.
The counterweight changes everything about how an elevator uses energy. Without it, a motor would need to generate enough force to lift the entire car and its passengers against gravity on every trip. With it, the motor only manages the surplus, typically a few hundred kilograms out of a 5,000-kilogram system. This is why elevator motors are measured in tens of kilowatts, not hundreds.
Modern traction elevators take this further with regenerative drives. When the heavier side descends (a full car going down, or an empty car with the heavier counterweight pulling it up), the motor does not need to add energy. Instead, it acts as a generator, converting the excess gravitational potential energy into electricity that feeds back into the building grid. In busy buildings, regenerative elevators recover 20 to 30 percent of their total energy consumption. The elevator is not just efficient; it sometimes produces power.
The cost of going higher
Every meter of height adds weight to the cables themselves. In the tallest buildings, the cables weigh more than the car, and engineers must use lighter materials or break the journey into segments.
The traction system scales beautifully up to about 500 meters. Beyond that, physics pushes back. A standard steel wire rope weighs roughly 1.6 kilograms per meter. In a 500-meter shaft, the cable run from car to counterweight and back is well over a kilometer. The cables alone can weigh more than the car they support. The counterweight can no longer balance the system at all floor positions because the cable mass shifts the balance point depending on which floor the car occupies. Engineers solve this with compensation ropes, additional cables hanging from the bottom of the car and counterweight to equalize weight as the car moves. But this adds complexity and cost.
For the very tallest buildings, like the 828-meter Burj Khalifa, a single elevator run from lobby to top is impractical. Instead, designers use sky lobbies: intermediate floors where passengers transfer between local and express elevators. Each elevator serves a portion of the building, keeping cable lengths manageable. The tradeoff is convenience. Getting to the 150th floor means two elevator rides and one transfer, not one continuous journey. Height demands compromise.
Before Elisha Otis demonstrated his safety brake at the Crystal Palace in 1854, buildings topped out at five or six stories because nobody would climb higher. The elevator did not just add a convenience; it inverted the value of height. Ground floors, once the most desirable, became commercial space. Upper floors, once servant quarters and storage, became penthouses. The counterweight made vertical cities possible by making vertical movement nearly free. Every skyline you have ever seen is a monument to a block of concrete you were never meant to notice.