Light bulb buying guide
LED, CFL and halogen lights: what's the difference and which is best?
Choosing the right lights
Light bulbs aren't as simple as they once were. We'll help you understand how to pick the right one for your needs.
- LED, CFL or halogen?
- Wattage and lumens: what do these mean?
- Costs of buying and running light bulbs
- Dimmable bulbs, colour temperature and other key specifications
Types of light bulb
Each type of light bulb (or lamp, to be technically accurate) has its pros and cons.
- LED (light-emitting diodes) are the latest in home lighting and in the last few years have rapidly moved from being new and expensive to just an everyday item. They can still be a bit more expensive than CFLs. They're very energy efficient and long-lasting (up to 10 times longer than CFLs), activate instantly and don't contain mercury. LED light bulbs are a good option for most lighting situations. CHOICE light bulb tests have focused exclusively on LEDs for the last few years.
- Compact fluorescent lamps (CFLs) are reasonably cheap, usually last for a few years and give good light. However, they tend to fade over time, and wear out faster if continually switched on and off or subjected to extreme heat or cold. They contain a small amount of mercury so you have to be careful about how you dispose of them. They can sometimes take a few moments to warm up to full brightness and can be difficult to fit into smaller light fittings. They have been largely superseded by LEDs now, but are still commonplace in most homes and are readily available in shops.
- Halogen lamps are a type of incandescent lamp. They're about 30% more efficient than old-style incandescent bulbs and are longer-lasting. They're likely to be found in homes as low-voltage downlights and in various special uses. They can be a good option when the light fitting is likely to be hot for long periods, as LEDs and CFLs can be sensitive to high heat.Note that low voltage doesn't necessarily mean low-energy consumption though. A typical low-voltage halogen downlight uses about 35W to 50W, plus another 10W for the transformer.
- Incandescent bulbs are simple and cheap to manufacture, but very inefficient to run compared to CFLs and LEDs; most of the electrical energy is converted into heat rather than light, so a 60W incandescent bulb only puts out as much light as an 8W LED. That's why they're now mostly phased out, but they're still available for specialty uses, such as in oven lights.
Wattage and brightness
Generally, for two light bulbs of the same type, the one that uses more watts will be the brighter. LED light bulbs use less power compared to CFLs, halogens and incandescent lights.
When CFLs first appeared, they usually had an "incandescent equivalent" guide on their packaging, to help consumers choose the right model (e.g. "equivalent to 60W"). But incandescent equivalence is an imprecise measure of light output, and in any case incandescent light bulbs have been largely out of the market for many years, so it won't mean much to many people these days.
Most lamps now state their light output in lumens (lm), which is more accurate and useful, as long as you know what the numbers mean.
How do lumens, incandescent wattages and actual LED/CFL wattages relate? Here's a rough guide:
- 420lm = 40W incandescent = 6W LED/ 7W CFL (suitable for a table or floor lamp)
- 800lm = 60W incandescent = 8W to 10W LED/ 12W CFL (to light a small room)
- 930lm = 75W incandescent = 10.5W LED/ 15W CFL (to light a medium-sized room)
- 1300lm = 100W incandescent = 13W LED/ 20W CFL (for a large room or work area where very bright light is needed)
- 2000lm light bulbs can also be found. These will typically be 18-20W LEDs.
Price and lifespan
LED light bulbs, and CFLs to a lesser extent, may look pretty expensive (especially if you're old enough to remember buying incandescent globes for less than a dollar each). Are LED light bulbs worth the price? The short answer is yes.
Here's a quick comparison of four light bulbs – LED, CFL, halogen and incandescent – and their costs for one year of use. We assume five hours' use per day and electricity price of 30c/kWh. These bulbs would be roughly equivalent in light output.
- 10W LED: Price $12. Yearly energy use 18.25kWh. Running cost $5.48.
- 12W CFL: Price $6.50. Yearly energy use 21.9kWh. Running cost $6.57.
- 46W Halogen: Price $2.90. Yearly energy use 83.95kWh. Running cost $25.19.
- 60W Incandescent: Price $1. Yearly energy use 109.5kWh. Running cost $32.85.
It's clear that despite their higher initial price, LED and CFL light bulbs pay for themselves quickly through their much lower running costs.
And remember that halogens and incandescents usually only last a year or two. Claimed life expectancy for CFLs typically ranges from 6000 to 15,000 hours (about three to eight years, assuming five hours' use per day). LED lamps claim 15,000 to 35,000+ hours (about eight to 19 years). Both types do fade over time, CFLs much more so than LEDs.
Our tests show that while a few LED light bulbs don't last the distance, most do, especially those from major brands. We've had several on test for 14,000 hours or more – up to 30,000 hours (equivalent to 16 years' use) in some cases. Read about what we've found.
So while the LED light bulb might look pricey, it's a much better bet in the long run. To get the best lifespan from your LED light bulbs, avoid putting them in small enclosed light fittings where the trapped heat will cause them to deteriorate faster.
Why do LED light bulbs cost more?
LED light bulbs have electronic circuits in their ballast (the base) to control the LEDs, so naturally they are more expensive than an incandescent or halogen bulb to manufacture. CFLs also have some electronics in their ballast.
While LED technology has been around for a long time, it's not been a simple process to develop it into a light bulb package suitable for home light fittings. LEDs are heat-sensitive, for example, so the light bulb has to be carefully designed to disperse heat effectively, otherwise the LED lifespan is drastically shortened.
If LEDs seem expensive, just think of this: the first LED light bulb on the market in Australia – the Philips Master LEDbulb 12W, back in 2011 – cost us $71.50 per bulb! Prices have come down as the technology became more common.
Features and specifications
Colour temperature is measured in kelvins (K) and is indicated on the lamp and its packaging.
- Warm white (3000K): yellowish light, similar to that from an incandescent bulb. This is a good choice for living areas and bedrooms, where a cosy, comfortable light is desired.
- Cool white (4000K): white light, similar to that from fluorescent tubes, and suitable for offices, kitchens, bathrooms and any other room where a whiter light is preferred.
- Daylight (5000K or more): blue-white light equivalent to outdoor daylight.
Colour rendering index (CRI)
This is a measure of the light bulb's ability to accurately show the colours of objects in the surrounding area, using bright natural light as a reference point. A CRI of 100 indicates perfect colour appearance, while a very poor colour rendering could rate zero or less. A light with excellent CRI should show the surroundings in the same colours you'd see in bright sunlight, while a poor CRI could cause odd red or blue tones to appear.
Most CFL and LED light bulbs have CRIs around 80 to 90. 90 and above is generally considered excellent, but for ordinary household use where exact colour rendering isn't necessary, 80 should be fine.
Note that CRI is not considered a perfect measurement for CFL and LED lights.
LEDs are usually bulb-shaped. CFLs are tubes, spirals or bulbs. The shape of a light bulb isn't a major factor in its brightness, but does determine the direction in which most light is thrown. A folded tube emits most of its light out of the sides and should be installed lengthways so the side faces out or down. A spiral emits light from its end and sides, so it suits most light fittings, but they can be too bulky for some. Some bulbs, particularly LEDs, emit light from only the top half and end of the bulb, so they're also better for downward or directional lights.
Many CFLs and LEDs are suitable for use with dimmer switches, but check the packaging to make sure you have the right type.
Most CFLs activate almost instantly with a reasonable light output, so they're usually fine for use in stairways, cellars and other areas where you need immediate, bright light. LEDs activate instantaneously and can be used in any area.
There's no performance difference between bayonet cap (BC) and Edison screw (ES) mounts on light bulbs. However, the light fitting's size, whether it has an effective reflector dish, the translucence of the glass and so on can make a big difference. Small enclosed light fittings can trap heat even from a CFL or LED light bulb and reduce its life, so a halogen lamp, which is less susceptible to heat, may be the solution in that case. Or, get a new light fitting.
CFL and halogen light bulbs range in price from about $2 to $8. LED light bulbs range in price from about $6 to $30+.