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How to buy the best light bulb

Halogen light bulbs explained

By Matthew Knight

Article 3 of 3

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Halogen light bulbs explained

Find out everything you need to know about halogen light bulbs.

Halogen light bulbs are now the closest you can get to old-style incandescent bulbs in terms of light quality. This type of bulb has a filament enclosed in halogen gas, so they can burn hotter than an incandescent but still use less energy.

Halogens use around 20-30% less energy than incandescent light bulbs, but halogens are still the most energy-hungry energy-saving bulb on the market. 

Halogen light bulbs don’t compare that well with other types of bulbs in terms of energy savings. LED bulbs use 90% less energy than a traditional bulb and CFLs (compact fluorescent lamps - the standard type of energy-saving bulb) use 60-80% less.

Halogens are the cheapest type of energy-saving light bulb and you can buy one for as little as £1. They are currently the most common kind of spotlight bulb and also come in a variety of classic bulb shapes. 

We've rounded up the pros and cons of halogen light bulbs. Once you've decided what type of bulb is right for you, go to our to see the top bulbs we recommend from our independent lab tests.

What are halogen light bulbs great at?

  • they are the closest to a direct replacement for an incandescent that you can get. They provide a similar warm light and are available in similar wattages.
  • halogens are the cheapest type of energy-saving bulb, so are a good choice for a light that you don’t have on too often, such as a garage or loft.
  • they get to their full brightness the instant you flick the light switch. You don’t have to worry about waiting for them to warm up, like you do with some CFL energy-saving bulbs.
  • halogens can be dimmed using a dimmer switch, just like an old incandescent – unlike some CFLs and LEDs.
  • the CRI or Colour Rendering Index is a measure of how well a light source accurately reveals various colours. Halogens are near perfect, getting CRI scores in the high 90s. LED and CFL bulbs can't match this, but are still above acceptable levels.

What are the downsides of halogen light bulbs?

Halogen bulbs are the least energy efficient of the new type of energy-saving bulbs, so unfortunately you won’t see big changes in your electricity bills.

Their lifetimes are much shorter than either LEDs or CFLs – so make sure you consider this when looking at the cheaper price of a halogen. A typical bulb should last you about 2,000 hours (roughly two years), compared with 25,000 hours (25 years) for LEDs and 10,000 (10 years) for CFLs.

Should I buy halogen bulbs?

Halogens won’t reduce your energy use as much as LEDs or CFLs, but if you're simply after a quick replacement in looks and performance for an old incandescent, this is your safest option.

They are a good choice if you don’t want to spend too much on a bulb that you don’t use that often, as it won't have much of an impact on your bills.

  • if you want to save a bit of cash on your energy bill, replace bulbs in your home that you use least often with halogens and use CFLs or LEDs for bigger energy savings on the lights that you use most often.
  • if you're particular about light quality and aren't looking to make drastic cuts to your energy bills, halogens are a good, safe and familiar option.

Pros: Warm, soft light that is almost identical to the light from traditional incandescents, cheapest type of energy-saving bulb to buy, instant light, dimmable 

Cons: Short lifetimes compared to LED and CFLs, not as energy efficient as CFLs or LEDs, higher wattages are being phased out

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