Choosing a Lightbulb

For your lighting needs LED is currently the best technology to use and will be for the foreseeable future. It is very energy efficient so it will reduce your power bills and it is very long lasting. So, it is important to get the selection of the light bulb right.
Before heading to the store there are several considerations that you should review before buying LED light bulbs. I have prepared the following descriptions and design tips to help you make the best selections and you can also download the guide right here from our site

Start at the base
The base of the lamp is its connection point to the light fitting. So, the base of the light bulb needs to fit the socket of the light fitting. This is the first characteristic of the lamp to get right, otherwise it will not fit in your light!

Generally, these bases come in two types, screw (denoted ES for Edison Screw) or bayonet (denoted BC for Bayonet Cap). But within these groups there are different sizes so it good to know the size and type you need before heading to the store.

Take the old light bulb you are replacing (even if it is different tech, for example fluorescent) with you to the store to match the base.

Size is important
Light bulbs also come in different shapes and sizes. For example, in decorative light fittings where the bulb is visible, it is usually a small decorative shape like a candle or fancy round bulb. In light fittings with shades or a diffuser, the bulb is not visible and is typically the traditional rounded shape.

  • As a general rule replace lamps with the same shape.
  • Always check the lamp you select is sized to fit though the opening in the shade or diffuser and it is short enough to be fully concealed.
  • Buy LED bulbs with a minimum 270-degree light output otherwise you may create shadows on the shade or diffuser.

Clear or Frosted
Typically LED light bulbs are frosted (milky finish) and work well in light fittings which have a shade or diffuser and where a general overall light effect is required. LED lights can also come in decorative shapes, for example tubular or candle shapes. Often these shapes have clear glass with the LED visible inside, sometimes shaped as the old-style filament. These give a great effect when the bulbs are visible in the light fittings.

  • Where the light bulb is hidden behind a shade of diffuser, use a frosted light bulb.
  • Where the light bulb is visible in the fitting, use a clear light bulb.

How Bright ?
We are used to understanding the brightness of a light bulb by its wattage. With the advent of LED this is no longer a good measure as the efficiency of LED light sources is rapidly changing. This means that 2 bulbs with the same wattage rating can give different levels of brightness. A better measure is Lumens (donated as lm) which is usually noted on the lamp box near the wattage.

  • A light bulb rated over a 1600lm is bright – roughly equivalent to the old 100W incandescent, 60W halogen or a 23W fluorescent.
  • A suitable bulb for a small table lamp is 450lm – roughly equivalent to a 40W incandescent or 9W fluorescent.
  • A suitable bulb for a floor lamp is 800lm – roughly equivalent to a 60W incandescent or 13W fluorescent.
  • Lighting rooms to suit their function so that different rooms have different moods and intensities.

Warm or Cool White ?
LED lighting comes in many different colours of white, these differences are noted in Kelvin (K). The colour of light has a physiological effect on us. Cooler colours help us concentrate, give us energy, but also upset our natural biorhythms at night as they contain higher amounts of blue spectrum light. Warmer colours of light are cosy, help us relax, they contain higher amounts of light in the red spectrum so help us to prepare for sleep. Colours of white light can be understood as follows: 2700K and less are warm colours of light, 3000K to 4000K are neutral colours of white light, 4000Kelvin and more are cooler colours of light.

  • Look for the Kelvin rating of bulbs on their boxes. Don’t be fooled by manufacturer terms of warm and cool light, 3000K light is not warm light.
  • Generally, use warm light (2700K or less) in your home at night, this will help prepare your body for rest.
  • Generally, use 4000K light for tasks, for example in desk lamps for work areas. However, don’t use these lights for long periods at night as it may disrupt your sleep.

Dimming is always a good idea but not always easy to do, especially when retrofitting. Firstly, not all LED light bulbs can dim. Then sometimes, even when a dimmable light bulb is used, diming is not possible as an existing dimming system may not be compatible with LED. If your dimming system is not compatible then a replacement system may be required. This does not need to be complicated, it can often be as simple as installing small dimmers at the light switch.

  • Manufacturers make both dimmable and non-dimmable LED light bulbs. Check the fine print on the box to make sure you get the right one. If you want dimming and it is not noted, don’t buy it.
  • If you are planning use a LED light bulb in light fittings that are dimmed, test a bulb first. Maybe you can find one from another fitting to test before you go to the store.

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