Putting spotlights under the spotlight – GU10 versus MR16

The GU10 and the MR16 are the main two spotlights used in the home today. Most people have them in their kitchens and/or lounges and unfortunately the existing halogen spotlights are incredibly expensive to run. Both types of spotlight are pretty similar in appearance but underneath the bonnet they are fundamentally different.

The main difference is that the GU10 bulb will run at 240 volts (which is the same voltage as supplied by the mains power supply), while MR16 bulbs run on just 12 volts.

As a result MR16 bulbs need an external transformer to convert the buildings main 240 volts mains supply to the 12 volts required to run the bulbs. With GU10s, you can simply plug in and you are good to go.

Retrofitting LED spotlights in your home

Halogen spotlights normally run at 50watts while their LED cousins run at just 5watts. Therefore it is certainly worth replacing them since you can produce massive savings on your electricity bills by doing so.

>>> Find out how much you could save by making the switch <<<

The first thing is to determine the type of spotlight you have in your home – you can use our diagram below to determine which one you have.

GU10 vs. MR16

So you have GU10 Bulbs…

If you have halogen GU10s firstly give yourself 10 seconds to feel smug – the LED bulbs will work perfectly straight out the pack and give you savings of over 90% on your energy bills.

The only thing to ensure is that you buy dimmable LED GU10s if you have a dimmer switch or non-dimmable if you have a normal switch in your home.

So you have MR16 bulbs…

Installing LED MR16’s is much less straightforward, however it is still a worthwhile process since replacing six halogen 50watt bulbs with six 5watt LED bulbs will result in substantial savings over a very short space of time (they tend to pay back in a little over a year despite being 10 times the price!)

The first thing you need to do is determine the existing type of transformer you have in your MR16 circuit. This will most likely be situated up in the roof above the light fittings – now in some circuits there is one transformer, but sometimes every individual light fitting has its own transformer. They tend to come in two varieties; the first is the older wire-wound magnetic transformers and the second is the newer electronic low-voltage transformer. Both work by stepping down the mains voltage (240v) to 12 volts, which allows the bulbs to function.

Now the older magnetic transformers will work perfectly with LED MR16s. The issue is that the electronic low voltage transformers may not. The reason for this is that they need a minimum voltage to pass through them to operate; for example the transformer in my kitchen is 40w – 400w. Historically there were 6 50w halogen bulbs in the circuit – giving a total load of 300w.

Replacing those 50w halogen bulbs with 5w LED equivalents will put a load through the transformer of just 30w in total. Therefore this means the transformer won’t work correctly and will probably result in your LEDs flickering. In this instance you need to replace the existing transformer in the circuit with an LED driver/transformer that is matched to operate on the total number of watts in your circuit.

Final thoughts – GU10 versus MR16

Now, in terms of ease, you can actually buy a GU10 LED bulb + a brand new GU10 fitting for just over £20 – so you can then ignore the MR16 transformer issue completely. However regardless with how you want to move forward, moving to LED bulbs is the future.

Using just 10% of the energy to power them means that they are going to deliver really significant savings on your energy bills. This blog looks at the sort of savings you could potentially make from the relatively simple swap.

>>> For our LED Buyers’ Guide please go here <<<


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