Lighting

Types of lightbulb

There are four main types of lightbulbs that are commonly used in domestic houses: incandescent, halogen, compact fluorescent (CFL), and light-emitting diode (LED).

Incandescent lightbulbs

These are the traditional lightbulbs that have been used for many years. They are relatively cheap and produce a warm, yellowish light. However, they are not very energy-efficient as light is generated by electricity passing through a thin wire (filament) and also produces heat, which in most cases is unnecessary.

Halogen

Another type of commonly used lightbulb these days, often in ceiling spotlights. They are a type of incandescent bulb that uses a halogen gas to increase the efficiency of the bulb. Halogen bulbs are more energy-efficient than traditional incandescent bulbs, but still less efficient than CFL or LED bulbs. They also produce a bright, white light and are available in a range of styles and sizes. However, they can get very hot and can be a fire hazard if they come into contact with flammable materials.

CFL

More energy-efficient than incandescent bulbs and can last longer, although the light can deteriorate over the years. They produce a cooler, bluish light and are available in a range of styles and sizes. You can usually spot these because there is a delay and often a flickering when they are initially switched on. However, some people find that the light they produce is not as pleasant as that produced by incandescent bulbs. Additionally, they contain small amounts of mercury, which can be harmful if the bulb is broken, so must be disposed of carefully.

LED lightbulbs

The most energy-efficient of the three types of lightbulbs and can last up to 25 times longer than incandescent bulbs. They produce a bright, white light and are available in a range of styles and sizes. They were originally much more expensive than incandescent or CFL bulbs, although prices have fallen dramatically their long lifespan means that they are much more cost-effective using up to 80% less energy than incandescent bulbs.

Things to consider

• Simply be careful about using more lighting than you need, whether it’s remembering to turn lights off when you leave the room, not having the room any brighter than you need , or having security lights that are triggered by a sensor that stays on too long.
• If you have old incandescent bulbs then consider switching to LEDs. These days the cost of LED lights is much lower with a very short payback time (see here), the quality of the lighting is better (e.g. you can get a nice warm white rather than cold blueish white).