Louver

A louver (American) or louvre (Commonwealth English; see spelling differences) is a framed opening fitted with horizontal slats in a structure. These slats (also sometimes called louvers/louvres) are angled to admit light and air, as well as to keep out rain and direct sunshine. The angle of the slats may be adjustable, usually in blinds and windows, or fixed, such as in exterior shutters.[1][2]

## Contents

* 1 History
* 2 Construction
* 3 Jalousies
* 4 Use
* 4.1 In architecture
* 4.2 In infrastructure
* 4.3 In transportation
* 5 See also
* 6 References

## History

Louvers originated in the Middle Ages as lantern-like constructions in wood that were fitted on top of roof holes in large kitchens to allow ventilation while keeping out rain and snow. They were originally rather crude constructions consisting merely of a barrel.

Later, they evolved into more elaborate designs made of pottery, taking the shape of faces where the smoke and steam from cooking would pour out through the eyes and mouth, or into constructions that were more like modern louvers, with slats that could be opened or closed by pulling on a string.[3]

## Construction

Modern louvers are often made of aluminum, metal, wood, or glass. They may be opened and closed with a metal lever, pulleys, or through motorized operators.[4]

The Australian Standard specifies requirements for the construction of buildings using louver in bushfire-prone areas in order to improve their resistance to bushfire attack from burning embers, radiant heat, flame contact and combinations of the three attack forms.[5][6] The revised building standard details various construction methods and materials that must be used depending on the homes level of bushfire risk. This includes changes to the window and glazing requirements for homes located in a Bushfire Attack Level category greater than BAL-Low.

## Jalousies

Often used interchangeably by mistake, the key difference between louvers and jalousies is that louvers are fixed position. Jalousies are installed within a movable adjustable mechanism which positions all jalousies into any parallel position with respect to each other.[7]

## Use

### In architecture

The belfry louvers of Sens Cathedral, France

Louvers are rarely seen as primary design elements in the language of modern architecture, but rather simply a technical device. Louvers are part of the design of Demerara windows to help keep 18th and 19th century buildings cool in hot climates and block direct sunlight.[8][9] Some modern louver systems serve to improve indoor daylighting. Fixed mirrored louver systems can limit glare and of redirect diffuse light. Such louvers may be integrated in between two panes of double glazing.[10] In industrial facilities such as steel foundries and power plants, louvers are very common. They are utilized for natural ventilation and temperature control.

Louvers are frequently found in bell towers, where they are utilised to let out as much sound as possible, while having the bells remain unexposed to the weather.

There are examples of architects who use louvers as part of the overall aesthetic effect of their buildings. The most well-known example is Finnish modernist architect Alvar Aalto who would create aesthetic effects in the facades of his buildings through the combination of different types and sizes of louvers, some fixed some moveable, and made mostly from wood (e.g., the various buildings of the Helsinki University of Technology). A second example, taking influence from Aalto, is the second-generation modernist architect Juha Leiviskä.

### In infrastructure

Louvers may be used as a type of flood opening, usually covered by one or more moving flaps. They are designed to allow floodwaters to enter and leave the building, equalizing hydrostatic pressure on the walls and mitigating structural damage due to flooding. Louver windows are a staple in the design of homes and perfect to withstand the pressures of future cyclonic conditions.[11] Cyclone homes have always been synonymous with louver windows, louver blades have been tested for 'debris type B' for cyclonic regions.

### In transportation

Louvers mounted to the rear window of a 1970 AMC Javelin

Rear window louvers are also available as an accessory for some automobiles. They have also been used over the years in hoods, trunk lids, and other various body panels; typically hot rods, but by no means exclusive to that period. Their purpose in this regard is both as a functional means of ventilation, but also as a styling modification.

Louvers are used as semi-passive means of thermal control on airplanes and spacecraft as well.[12]

Louvers may also be used on traffic light lenses to prevent traffic from seeing the wrong traffic signal.

## See also

* Air conditioning
* Jalousie window
* Window shutter

## References

Notes

1. ↑ "louver". https://thefreedictionary.com/louver.
2. ↑ "Shutters vs. Blinds". Shuttercraft Ltd. https://shuttercraft.co.uk/blog/window-dressings/what-should-i-choose-shutters-vs-blinds.
3. ↑ Henisch (1976), pp. 96–97.
4. ↑ "Louver from "Encyclopædia Britannica"". Encyclopædia Britannica. https://www.britannica.com/EBchecked/topic/349399/louver. Retrieved 2014-03-02.
5. ↑ "Specifying Louvres in Bushfire Prone Areas" (in en-AU). 2018-09-18. https://safetylinejalousie.com.au/specifying-louvres-in-bushfire-prone-areas/.
6. ↑ "Building in designated bushfire prone areas". Department of Transport and Planning. Shade It. 2023-11-21. Retrieved 2025-10-08.
7. ↑ Architectural Terms & Definitions Textbook
8. ↑ Rory, Westmas (2010-05-31). "Architecture - Building Under the Sun". Stabroek News. https://www.stabroeknews.com/2010/guyana-review/05/31/architecture/.
9. ↑ Haley, Murtland (2017-04-23). "The Demerara Window – the Colonial 'AC'". Kaieteur News. https://www.kaieteurnewsonline.com/2017/04/23/the-demerara-window-the-colonial-ac/.
10. ↑ Dariusz Heim and Kamil Kieszkowski: Shading Devices Designed to Achieve the Desired Quality of Internal Daylight Environment , PLEA2006 - The 23rd Conference on Passive and Low Energy Architecture, Geneva, Switzerland, 6–8 September 2006
11. ↑ "A Timely Reminder Why Louvre Windows Were Specified in Queensland Cyclone Shelters" (in en-AU). 2017-03-29. https://safetylinejalousie.com.au/a-timely-reminder-why-louvre-windows-were-specified-in-queensland-cyclone-shelters/.
12. ↑ "Frequently asked questions / Rosetta / Space Science / Our Activities / ESA". http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions. "The system devised for Rosetta employs several new techniques, including the installation of louvres over the radiators, to keep spacecraft hardware at proper operating temperatures"

Bibliography

* Henisch, Bridget Ann Fast and Feast: Food in Medieval Society. The Pennsylvania State Press, University Park. 1976. ISBN 0-271-01230-7
* "Foundation Flood Vents". National Association of Home Builders (NAHB) Research Center. 2001. http://toolbase.org/about.aspx.

* v
* t
* e

Heating, ventilation, and air conditioning

Fundamental concepts|

* Air changes per hour
* Bake-out
* Building envelope
* Convection
* Dilution
* Domestic energy consumption
* Enthalpy
* Fluid dynamics
* Gas compressor
* Heat pump and refrigeration cycle
* Heat transfer
* Humidity
* Infiltration
* Latent heat
* Noise control
* Outgassing
* Particulates
* Psychrometrics
* Sensible heat
* Stack effect
* Thermal comfort
* Thermal destratification
* Thermal mass
* Thermodynamics
* Vapour pressure of water

Technology|

* Absorption refrigerator
* Air barrier
* Air conditioning
* Antifreeze
* Automobile air conditioning
* Autonomous building
* Building insulation materials
* Central heating
* Central solar heating
* Chilled beam
* Chilled water
* Constant air volume (CAV)
* Coolant
* Dedicated outdoor air system (DOAS)
* Deep water source cooling
* Demand-controlled ventilation (DCV)
* Displacement ventilation
* District cooling
* District heating
* Electric heating
* Energy recovery ventilation (ERV)
* Firestop
* Forced-air
* Forced-air gas
* Free cooling
* Heat recovery ventilation (HRV)
* Hybrid heat
* Hydronics
* HVAC
* Ice storage air conditioning
* Kitchen ventilation
* Mixed-mode ventilation
* Microgeneration
* Natural ventilation
* Passive cooling
* Passive house
* Radiant heating and cooling system
* Radiant cooling
* Radiant heating
* Radon mitigation
* Refrigeration
* Renewable heat
* Room air distribution
* Solar air heat
* Solar combisystem
* Solar cooling
* Solar heating
* Thermal insulation
* Underfloor air distribution
* Underfloor heating
* Vapor barrier
* Vapor-compression refrigeration (VCRS)
* Variable air volume (VAV)
* Variable refrigerant flow (VRF)
* Ventilation

Components|

* Air conditioner inverter
* Air door
* Air filter
* Air handler
* Air ionizer
* Air-mixing plenum
* Air purifier
* Air source heat pumps
* Automatic balancing valve
* Back boiler
* Barrier pipe
* Blast damper
* Boiler
* Centrifugal fan
* Ceramic heater
* Chiller
* Condensate pump
* Condenser
* Condensing boiler
* Convection heater
* Compressor
* Cooling tower
* Damper
* Dehumidifier
* Duct
* Economizer
* Electrostatic precipitator
* Evaporative cooler
* Evaporator
* Exhaust hood
* Expansion tank
* Fan coil unit
* Fan filter unit
* Fan heater
* Fire damper
* Fireplace
* Fireplace insert
* Freeze stat
* Flue
* Freon
* Fume hood
* Furnace
* Furnace room
* Gas compressor
* Gas heater
* Gasoline heater
* Geothermal heat pump
* Grease duct
* Grille
* Ground-coupled heat exchanger
* Heat exchanger
* Heat pipe
* Heat pump
* Heating film
* Heating system
* High efficiency glandless circulating pump
* High-efficiency particulate air (HEPA)
* High pressure cut off switch
* Humidifier
* Infrared heater
* Inverter compressor
* Kerosene heater
* Louver
* Mechanical fan
* Mechanical room
* Oil heater
* Packaged terminal air conditioner
* Plenum space
* Pressurisation ductwork
* Process duct work
* Radiator
* Radiator reflector
* Recuperator
* Refrigerant
* Register
* Reversing valve
* Run-around coil
* Scroll compressor
* Solar chimney
* Solar-assisted heat pump
* Space heater
* Smoke exhaust ductwork
* Thermal expansion valve
* Thermal wheel
* Thermosiphon
* Thermostatic radiator valve
* Trickle vent
* Trombe wall
* Turning vanes
* Ultra-low particulate air (ULPA)
* Whole-house fan
* Windcatcher
* Wood-burning stove

Measurement
and control|

* Air flow meter
* Aquastat
* BACnet
* Blower door
* Building automation
* Carbon dioxide sensor
* Clean Air Delivery Rate (CADR)
* Gas sensor
* Home energy monitor
* Humidistat
* HVAC control system
* Intelligent buildings
* LonWorks
* Minimum efficiency reporting value (MERV)
* OpenTherm
* Programmable communicating thermostat
* Programmable thermostat
* Psychrometrics
* Room temperature
* Smart thermostat
* Thermostat
* Thermostatic radiator valve

Professions, trades,
and services|

* Architectural acoustics
* Architectural engineering
* Architectural technologist
* Building services engineering
* Building information modeling (BIM)
* Deep energy retrofit
* Duct leakage testing
* Environmental engineering
* Hydronic balancing
* Kitchen exhaust cleaning
* Mechanical engineering
* Mechanical, electrical, and plumbing
* Mold growth, assessment, and remediation
* Refrigerant reclamation
* Testing, adjusting, balancing

Industry organizations|

* ACCA
* AHRI
* AMCA
* ASHRAE
* ASTM International
* BRE
* BSRIA
* CIBSE
* Institute of Refrigeration
* IIR
* LEED
* SMACNA

Health and safety|

* Indoor air quality (IAQ)
* Passive smoking
* Sick building syndrome (SBS)
* Volatile organic compound (VOC)

See also|

* ASHRAE Handbook
* Building science
* Fireproofing
* Glossary of HVAC terms
* World Refrigeration Day

* Template:Home automation
* Template:Solar energy

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