Tips for choosing energy-saving light bulbs

13 November 2014

A guide to energy-saving light bulbs: which ones to choose, safety tips and how to save money.

Check the brightness of your energy-saving light bulbs

Although the brightness of energy-saving bulbs is measured in lumens not watts, there are also different wattages for energy-saving light bulbs that it's worth being aware of, so you choose the correct ones for your needs - especially if you are replacing traditional light bulbs.

If you want to replace a traditional light bulb with an energy-saver that offers the same level of illumination, you need to understand how brightness is measured in the new light bulbs.

Traditional light bulbs had a certain wattage – 40w, 60w or 100w, for example.

But the brightness in energy-saving light bulbs is measured in lumens.

Read our FAQs on energy-saving light bulbs.

How to convert watts into lumens

To get the same brightness as an old-style 40w bulb, you’ll need a new bulb that offers more than 400 lumens

A 6w LED bulb would do the job, for example; this gives you an idea how much less energy these bulbs consume.

Your new light bulb's packaging should tell you what wattage of traditional light bulb they are designed to replace.

If you are specifically looking for a replacement for an old-style incandescent 60w bulb, you’ll need an energy-saving bulb that emits more than 700 lumens to get the same level of brightness.

With a CLF, this means at least a 12w light bulb, a 42w-53w halogen light bulb or a 10w LED light bulb. And look for a light bulb which emits “warm white” light.

The glow from energy-saving bulbs can range from blue to warm yellow: check the packaging before you buy.

Read our safety tips for using energy-saving light bulbs.

Which energy-saving light bulbs offer the biggest savings?

The more you use an energy-saving light bulb, the more you should save. 

LEDs are the most expensive, but you will recoup the initial expense more quickly if they used frequently and for long periods, such as in a kitchen or living room.

It can be worth paying more for a light bulb which will light up more quickly or last longer. 

What shape energy-saving light bulbs should you choose?

Take the bulb you’re replacing with you to the shop to make sure you get the right type of fitting.

Your fitting may have the correct code on it. This could be B22 or B15 for bayonets, or E4 and E27 for screw-ins. So make a note of this to ensure you get the correct match.

Find out more about energy-saving light bulbs.


The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.