Lighting

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Corner of typical lounge

Lighting Types

Filament

Filament

Filament Lamps made up most of Britain's domestic lighting until very recently.

  • GLS lamps (general lighting service) radiate light in all directions
  • R reflector lamps roughly double the light intensity in one direction
  • PAR lamps produce a narrower beam than R types, and can triple light output in one direction.
  • Tubular filament lamps (221mm & 284mm) are especially inefficient, and designed to lower safety standards
  • See Filament lamp

Halogen

Halogen

Halogen lamps are a type of filament lamp offering a compact light source, slightly better efficiency and better colour temperature. Some halogens have safety issues, and most halogen lighting installations have very low energy efficiency.

CFL

CFL

CFL lamps reduce energy use and total lighting cost, and most have very long lives. Light quality varies from one brand to another, and the quality of light is not to everyone's taste. Power equivalence markings are seldom realistic.

Linear Fluorescent

Fluorescent

(& circline)

Fluorescent lighting is highly efficient, and tube life excellent. The large sizes of linear tubes are often an issue in domestic situations. Tube light quality varies from very good to atrocious, and poor quality bare bulb fittings that flicker and flash are common, despite the existence of vastly better types. So its easy to get fluorescent lighting wrong.

Most circline fittings date from the 1960s, and a lot are of poor quality.

See Fluorescent Lighting

Mercury

Mercury discharge lamps produce an ice cold white light, and were widely used as street lighting in the 1980s.

Mercury discharge are now obsolescent. They give a poor quality white light at around 42 lumens per watt, CFL and linear fluorescent provides better energy efficiency and better light quality. For streetlighting and large yards, high pressure sodium give much better efficiency with low but acceptable CRI.

Metal Halide

Metal halide produces good light quality at high power with very high efficiency. However upfront cost is high, and the reputation for bulb explosions doesn't endear them to domestic use.

See Discharge Lighting

Sodium, High Pressure

High pressure sodium lighting is popular outdoors in towns today. It gives a golden light colour. It delivers excellent energy efficiency, but is slow to warm up and not white.

Sodium, Low Pressure

Sodium street light

Low pressure sodium lighting gives a pure yellow monochrome light, and is popular for lighting roads, car parks and yards. It has exceptionally high energy efficiency, much higher than all other lighting types, but has several downsides. The eye can't perceive any colour under pure yellow light, and the lamps take nearly 10 minutes to warm up. They also aren't dimmable (though slight dimming is possible with the right dimmer)

LEDs

LED

LEDs are promoted as filament lamp replacements. Light quality is variable. Light output has now reached 60-100w equivalence. LEDs are long lived, but the extremely long lives of indicator LEDs don't apply to lighting LEDs, and some don't last well in reality. Equivalent lamps need to be picked by lumen output not watts, LED efficacy varies.

Light Pipes

Light pipes are mirrored tubes that carry skylight from above the roof down to an interior light, providing lighting for rooms with no windows. They're expensive to fit, but cost nothing to run.

In high tech lighting systems used in some large buildings, light pipes are combined with fluorescent lights in the same enclosures. The electric light is used at night, and in the day the power is continually adjusted as needed to give the required light output. This means the electric lighting is off most of the day, but will gradually come on as daylight fades and on dark dull days. In a tower block the resultant power savings can be substantial.


Gas light

Rarely used for home lighting, but still used & manufactured, gas lights are an option for emergency lights that are not connected to the mains. Gas lighting has much better long term reliability than battery based electric lighting, low setup cost and minimal maintenance cost.

Vented gas lighting is an option for off-grid homes, where the cost of additional electrical capacity for lighting is high.

Gas lighting mantles are fragile, but when fixed in place permanently can have extremely long life.

Link here to the story of the walled up gaslight

Candles

Tea light candles 2579-3.jpg

Candles are the least energy efficient of all common lighting sources.

The use of candles in a power cut is a known fire risk. A small sconce mounted to a plastered wall eliminates most of the risk.

Solar Mirrors

Outdoor mirrors can be used to reflect skylight and often sunlight into a room to lighten the room and reduce electric lighting use. They also harvest a small amount of heat in winter, which can offset the cost.

Fitting large exterior mirrors is something few choose, but small ones are unobtrusive and improve interior light levels.

See Solar Mirrors

Heliostats

A heliostat is a reflective dish that moves, directing light to a fixed position. A tracking heliostat can be used to provide sunlight during the day, and moonlight or streetlight at night.

When used for lighting, the heliostat should be shaped to avoid concentrating light to a point, to avoid a fire risk. Some difference between horizontal and vertical geometry can give a line instead of a point at the focus. When satellite dishes are reused for this, they can be bent slightly to spread the point of focus.

Heliostats can also be made from flat sheet material fitted with lots of small angled reflectors. See: Solar furnace


More Topics

The lighting category lists the main lighting topics covered on this wiki:

Many more topics are covered within articles with other names, including:

Bad Ideas - Lighting

  • 500w Halogen Lights
  • Bare Fluorescent Lights with random tube
  • Lights high up out of reach over stairs
  • Plaster half-bowl uplighters

Fluorescent Lighting

  • Can I re-use my scanner/monitor CCFL?
  • Plant Lighting

Halogen Lighting

Rewiring Tips

  • Uplighters
  • Kitchen worktop lighting
  • Filament Strip Lights
  • Kitchen worktop lighting
  • Stair Lighting
  • Emergency lighting
  • MCB Type
  • Light Switch Controls Plugged in Lamps
  • Cutting costs
  • Futureproof Fitting Choices
  • Bulb Bases, BC ES & Miniatures
  • Bulb selection
  • Relamping Access
  • Outdoor Security Lighting
  • Tree & Shrub Lighting
  • CFLs outdoors
  • Making Outdoor Lighting Look Good
  • Outdooor Light Fitting Corrosion
  • Night Lighting


Lamp Life

  • Facilities lamps
  • The 900,000 hour light bulb
  • Boosting light output
  • Dimming
  • Rough Service Lamps
  • Photographic bulbs

Uplighters

  • Half moon plaster uplighters
  • R80 Spotlight Fittings
  • PAR38 spotlight fittings
  • Trough Fluorescent Lighting
  • Shelf Fluorescent Lighting


There are also many lighting relevant topics in Category:Electrical


See Also

Wiki Contents

Wiki Subject Categories