Article updated: 8-09-2026
Going up to the top floor of a building and pressing a button is such an everyday gesture that almost no one stops to think about it. However, behind that metal door lies a work of engineering that has transformed modern architecture.
In the mid-19th century, cities were growing upwards. The big challenge was not to build taller buildings, but to ensure that people could climb them without getting exhausted. The answer came from technology: the force of water and steam gave way to the piston, and soon after electricity revolutionized vertical transport.
Today, the lifting market is mainly divided into two large families: the electric elevators and hydraulic elevators. Although both fulfill the same mission, they operate on completely different physical principles. In this guide we explain in a simple way how each one works and which one best suits each type of building.
Differences between an electric elevator and a hydraulic one
The fundamental difference between the two lies in the source of electromechanical force and the pushing or dragging mechanism:
- Electric elevator: It works by traction. An electric motor machine moves a pulley along which steel cables (or synthetic tapes) run. The cabin hangs on one side and a counterweight on the other. The cabin is «pulled» from above.
- Hydraulic elevator: It works by pressure of fluid. A power plant generates pressure using a synthetic or ecological oil that pushes a steel piston. This piston is responsible for raising the cabin from below or by means of a lateral pull. To go down, it does not require engine power: simply open a valve for the fluid to return to the tank due to the gravity of the cabin itself.
To learn more about how pistons work, visit our article Piston position and type of traction
How an electric elevator works
The electric or traction elevator is the most recognizable in high-rise buildings. Its technical principle is reminiscent of a well-balanced rocker arm.
Cable and pulley traction system
The tractor machine transmits the movement to a pulley with grooves. The steel cables are attached to this pulley. Due to the friction between the cable and the throat, turning the pulley moves the cabin.
Counterweight or without counterweight
- With counterweight: It's him standard system. The counterweight weighs the same as the empty cabin plus 40-50% of the maximum authorized load. Thanks to this balance, the motor only performs the force equivalent to the extra mass, saving a lot of energy.
- No counterweight (drum or winding elevators): The cable is wound directly onto a rotating drum. Since they do not have a counterweight, they make better use of space, but require more powerful motors and consume more electricity.
With machine room vs MRL
- With traditional machine room: The machinery is housed in a specific room located above the gap (or at the bottom).
- MRL (Machine Room Less or Without Machine Room): Modern technology allows reduced permanent magnet motors to be installed within the cabin opening itself, eliminating the need to reserve a dedicated room.
How a hydraulic elevator works
If the electric elevator pulls upwards, the hydraulic one pushes. It is a technology admired for its smoothness and its enormous load capacity at low and medium heights.
Hydraulic power plant, piston and valve group
The system consists of three key elements:
- Hydraulic power plant: The hydraulic power plant It is a fluid reservoir with a submerged pump.
- Valve group: He valve group It is the regulatory «brain» that controls the flow of oil so that starts and brakes are imperceptible.
- Piston: He elevator piston It is a telescopic steel cylinder that expands with the entry of fluid and is collected when it returns to the tank.
1:1 direct drive vs 2:1 differential
- Direct (1:1): In the direct tractionThe piston is connected directly to the base of the cabin. For every meter the piston rises, the cabin rises one meter. Ideal for very short journeys or large load capacity.
- Differential (2:1): The piston has at its end a pulley through which a fixed cable passes to the pit. When the piston moves one meter, the cabin travels two meters. It allows you to double the travel with a piston half as long.
Without machine room
One of the The biggest advantages of the hydraulic system are that it doesn't require technical space on top. The hydraulic power plant and the operating panel fit in a compact wardrobe approved that can be installed anywhere in the building (in the garage, under the stairs or next to the moat), facilitating architectural design.
Comparative table between electric and hydraulic elevators
| Feature | Electric elevator (MRL) | Hydraulic lift |
| Operating principle | Calbe traction/counterweight | Oil/piston pressure thrust |
| Optimal route | Medium and high heights (no limit) | Low and medium heights (up to 6-8 floors) |
| Standard speed | From 1 m/s to more than 2.5 m/S | from 0.63 m/s to 1 m/s |
| Gap space | Requires larger space for overtravel | Ultra optimized hole (maximum cabin) |
| Location of machinery | In the gap (MRL) or upper quarter | Metal cabinet on any floor |
| Rescue in power outage | Automatic by optional batteries | Very simple automatic/manual by gravity |
Energy efficiency: Which one consumes the least?
Evaluate the efficiency of an elevator It depends not only on the nominal power of the engine, but also on actual usage and the type of daily maneuver.
The electric one with frequency converter and downward recovery
In a modern electric elevator, the use of the frequency converter (VVVF) allows progressive starts without voltage spikes. In addition, regenerative systems transform the mechanical energy generated when the cabin goes down loaded (or up empty) into electricity returned to the building's grid.
Hydraulic without downhill consumption and with ecological fluid
In the hydraulic elevator, the electric motor only works during the climb. During the descent, the pump is off; gravity evacuates the fluid from the piston to the tank completely free of charge in terms of kilowatts.
Furthermore, the use of biodegradable biological fluids minimizes environmental impact and improves the thermal performance of the installation.
Installation and maintenance cost
Initial cost: Which is the most economical?
As a general rule, about the cost of installing an elevator, The hydraulic elevator is more economical in the initial purchase and installation. It requires less complex structures at the top of the building and transmits mechanical loads directly to the pit floor, reducing architectural reinforcement work.
Long-term maintenance cost
The hydraulic elevator has fewer parts subject to constant friction wear (lacks counterweight, extensive direct-draft suspension cables, etc.), which simplifies its periodic inspections. Electric traction requires a higher initial investment, but it amortizes electricity consumption in buildings with a high volume of daily trips.
Which one to choose according to the type of project?
There is no technology better than another in absolute terms; there is the right technology for every need.
Medium-high height residential buildings
For farms of More than 5 or 6 floors with heavy local traffic; the ideal option is the electric elevator traction. It guarantees speeds exceeding 1 m/s and speeds up waiting times
Buildings with few floors and small openings
In single-family homes or residential buildings up to 8 stories high, the hydraulic elevator It takes advantage of the available space up to 15% more than an electric vehicle with a counterweight.
Neighborhood communities with a tight budget
In old buildings that install elevators for the first time (rehabilitations), the hydraulic with compact cabinet It is usually the optimal response in neighborhood communities, since it requires less initial investment, does not overload the roof structure and does not require complex works in the attic.
Industrial buildings and forklifts
For the transport of large loads (cars, heavy goods, forklift industrial), the hydraulic technology She is the undisputed queen thanks to her ability to directly push tons of weight with complete stability.
Frequently asked questions
Can a hydraulic system reach the same speed as an electric one?
Conventional hydraulics operate between 0.16 m/s and 0.63 m/s (and can reach 1 m/s), which is ideal for few plants. Electric ones are designed to travel at 1 m/s, 1.6 m/s or much higher speeds in skyscrapers.
Which one needs more maintenance?
Both systems legally require the same maintenance reviews preventive. However, the hydraulic system exhibits less mechanical wear due to continuous use because it does not have permanent friction traction cables or heavy counterweight suspension.
Do they both comply with the same safety regulations?
Yeah. Both electric and hydraulic vehicles marketed in the European Union must strictly comply with the elevator directive 2014/33/EU and the EN 81 standard (EN 81-20 and EN 81-50), guaranteeing identical levels of protection for users.
Can a hydraulic system be replaced with an electric one in an existing building?
Technically it is possible, but it requires a prior structural study. When switching from hydraulic to electric, it is necessary to evaluate whether the building structure supports the loads suspended from the roof of the opening and whether there is space to house the counterweight.
Bibliography
UNE-EN 81-20 and UNE-EN 81-50 standards: Safety rules for the construction and installation of elevators.
Both rules are paid. Fact sheets in AENOR store: UNE-EN 81-20:2020 — AENOR Store; UNE-EN 81-50:2020 — AENOR Store
Directive 2014/33/EU of the European Parliament and of the Council on elevators and safety components for elevators. Full text in EUR-Lex: Directive 2014/33/EU — EUR-Lex
Janovsky, L. (1999). Elevator Mechanical Design (3rd ed.). Elevator World Inc.
Available for purchase at Elevator Books: Elevator Mechanical Design — Elevator Books
Miravete, A. & Larrodé, E. Elevators: Principles and innovations. Reverté Publishing House. Elevators: Principles and innovations — Reverté Editorial
Postgraduate in Product management at Eada Business School. Qualification in Project Manager and Community Manager from Cecot. Responsible for Marketing and Communication at GMV Eurolift SAU since 2010.
