How to choose LED light globes

The first thing that most people shopping for LED globes notice is the price – they’re usually a bit more wallet-hungry than the compact fluorescent lamps (CFLs) or the halogen dichroics that you’ll find in many Australian homes. This initial price shock tends to dissolve pretty quickly though, when people get a better understanding of what they’re buying, how long it’ll last and the value for money that LED lights generally offer.

LED lamps don’t use the same kinds of technology as incandescent or fluorescent bulbs, and the things you need to consider when you’re choosing them are a little different. Below is a simple(ish) guide explaining what you should be looking for when you buy LEDs:

Step 1: Figure out what type of LED lighting you need

The first step is to figure out what type of luminaires you need (luminaire's a fancy French word, and an industry term for 'light fixture').

If you’re just replacing a globe it's likely to be an obvious choice (and you can skip this step), but if you’re planning a new lighting scheme, you’ll need to understand a bit about good lighting design, and what you want the light to achieve. Is it task lighting for a specific job? Or is it general lighting to light up a room? Perhaps accent lighting to show off a particular architectural feature or artwork? Different lamps will fulfil these purposes in different ways.

In most cases, you’ll need to choose either:

• A downlight - directional, good for general, task and accent lighting
• A general purpose globe - omnidirectional, good for general / ambient lighting
• A tube style globe like a long fluorescent tube - LED versions are available - omnidirectional and good for general lighting

Step 2: Choose or identify the mounting type

Different bulbs mount in different ways. Here's a guide to the common types of mounting options you’ll most likely need to choose from:

General purpose household lighting
Edison screw mount -typically E27 or E14 (‘E’ stands for Edison, either 27mm or 14mm screw diameter)
Bayonet mount – typically B22 or B15 (‘B’ for bayonet, 22mm or 15mm diameter)
Downlights
GU10 – This has two thick, nubby heads, and is twisted into place. Downlight lamps with this type of mount are 240V lamps, and don’t require an additional transformer.
MR16 – This mounting has two narrow, nail-like pins, and runs on 12V power – which means lamps of this type require a driver or transformer. The driver will need to be designed specifically for use with LED lights - it's not a good idea to try and reuse existing drivers from a halogen dichroic downlight setup.

Step 3: Choose the right beam angle (downlights)

General purpose household globes will cast light in every direction like a traditional incandescent (or 'GLS') globe would, so if that's what you're after you can skip this step.

If you’re buying downlights, it’s important to understand that they’re 'directional' - and that you’ll need to choose downlights with the correct beam angle for your purposes. The ‘beam angle’ determines the width of the beam coming from the globe.

For a 2400mm ceiling, a 60 degree beam angle should be fine, but you may want to test to be sure. Lower ceilings are likely to require wider beam angles (e.g. 100-120 degrees), and higher ceilings are likely to require a narrower beam angle.

If you’re after a reasonably consistent coverage on the floor, the beams should intersect at about 1100mm (a bit over a metre) above the floor surface. For a 2400mm ceiling with 60 degree beam angles, this means you'd need to space the lights out at about 1200mm intervals.

Step 4: Decide on the lumen intensity

It used to be that you could get a clear enough idea of how intense a bulb would be from its wattage. A 100W incandescent bulb would be bright, and 40W bulb would be dim. This kind of logic doesn’t apply to LED lighting though. As the technology improves, the power LED lamps use to create an equivalent amount of light is going down - and it varies from model to model.

What you’ll need to look for when deciding on the intensity of your LEDs is the lumen output (e.g. 250lm).

Lumens are a measure of what's known as 'luminous flux' - basically the total amount of light that’s put out by the globe. General purpose non-directional globes often give you a fighting chance by saying 'Equivalent to a 100W incandescent globe' or something similar – but take these with a pinch of salt because these claims are often a bit generous. Wherever you can, try look for the lumen output number rather than these (sometimes dubious) equivalence claims.

Below is a guide outlining what you should probably be looking for in terms of lumen outputs:

When it comes to downlights, things get a bit murkier. The older-style halogen downlights only really came in 35W and 50W varieties, with varying lumen outputs. LED downlights are likely to have a lumen output of anywhere between about 350 lumens and 1000 lumens. Dimmable ones are also available.

Step 5: Choose a colour temperature

You might have noticed that some lights are yellowish, and some are bright white or even bluish - this is because of the ‘colour temperature’ they’re designed to produce. If you hadn’t given it much thought, chances are you’ll notice it everywhere from now on...

Without going into all the psychology behind colour temperatures (it makes a surprising difference), as a rule of thumb you’ll want ‘warmer’, more yellowish colour temperatures in living areas to make them feel more comfortable, and cooler colour temperatures in the parts of your house where you need to be alert and see what you’re doing.

Below’s a basic guide to the colour temperatures that are usually appropriate for different parts of your home:

Step 6: Compare wattages

It's likely that many LED lamps will have different lumen outputs for similar wattages. 'Lumens per watt' is a good way to think about how efficient an LED globe is.

If there are two otherwise identical bulbs and one has a significantly lower wattage for the same lumen output, it may be worth thinking about how much money that’ll save over decades of use.

If the price isn’t that much more to begin with, paying extra for a lower wattage globe could easily be worth the difference.

Step 7: Look at the rated lifespan

The rated lifespan for an LED globe isn’t actually a guess about when it'll die. LEDs probably won't die for decades, unless they’re badly built or improperly installed. Instead, the amount of light they produce slowly fades over time.

The generally accepted measure for the lifespan of an LED globe is when it’s lost 30% of its original intensity – this is known as its L70 rating. Many modern LED bulbs claim to have an L70 lifespan of about 50,000 to 60,000 hours. In real terms, that would mean that you could probably expect about 50 years worth of use out of an LED globe with this L70 rating if it was used for a few hours a day.

In reality, these ratings are often an educated guess (or in the worst of cases a bit of a marketing gimmick). A lot of manufacturers don't test the lifespans of their LEDs under transparent, standardised laboratory conditions.

Good quality LED lights should have a minimum lifespan of between 20,000 and 40,000 hours... but it's far more important that you consider the things listed in step 8.

Step 8: Warranty, brand and quality

(Easily the most important part of your choice!)

Remembering that pretty much all LED globes are rated to last for decades, it's well worth paying close attention to the warranties on different products. The cost for a house full of LED lighting can certainly add up. A manufacturer's warranty is often a good indication of quality, which is a big consideration when you realise how many low-quality LED products there actually are on on the market.

Look for a warranty of at least two or three years - some manufacturers offer much longer warranties though.

Even more importantly, look for brands that have been around for a long time, and which have a presence in Australia that extends beyond a single distributor or importer (who could very easily disappear before your warranty runs out). A generous five year warranty isn't worth a damn if the only dealer in the country has skipped town!