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Low Voltage Lighting - Why?

Gone are the days were we had to replace our 100w incandescent bulbs every 6 months because one day when you walked into the room and turned on the light, 'POP'; goes another light. 

Now as everyone is aware, LED lights are taking over! This is brilliant for energy bills and having lamps that actually last many years instead of many months. 

Because of this rush of technology, many manufactures are knocking out lamps and bulbs faster and faster. Which doesn't actually mean the quality is there and that they will live up to their tag line 'Up to 25 year life span'. 

Companies such as Osram, Civilight and Samsung do make brilliant lamps, fittings and bulbs, however; these are not always cheap. 
That's what it comes down too though, cost. Just as most things in life. 

If you pay £5 for a pack of 10 GU10 LED replacement lights that you got from your local super market, it's likely these won't be the best quality.
If you pay £10 for a pack of 3 Osram LED replacement lights, you are more likely to get a decent light. 

Problems with 240V LED: 

Lighting.

- Power supply in each bulb
When this gets too hot and cannot distribute it's heat out anywhere it can fail. With this normally sending a current back down the circuit, blowing the breaker in the home fuse box.

- Fading/Yellowing
Some cheaper LED lights that state 'Warm White' are not true WW but are just painted. Which means when the light gets hot, fading and yellowing happens around the light and this causes shine problems

- Cost to Dim
Traditionally cost of dimming 240V LED lights can be expensive because the right lamps and dimmer switch will set you back about £100 per circuit (plus fittings).

So Why 24V

Traditionally low voltage lighting (true name SELV , separated extra low voltage) like 12V MR16 or the odd cheap LED tape. Even boat lighting is normally 12-24V.

Now 24V lighting is becoming more and more popular due to the quality increase and long term efficiency that these lights offer.

 - Power supply before the lights
A power supply/transformer will still be required but at least there will not one per lamp and inside the bulb itself. The power supplies used will be before the lighting & control circuit, this would allow direct drive of 24V to the light making it more efficient and robust. 

- Better quality of dimming
When dimming low voltage lights, the process is normally PWM (pulse width modulation). This is where the light turns on and off very quickly in a short time, to allow the light to dim. In normal 240V dimming, leading and trailing edge is used. 
PWM allows better dimming control and smoother lights, plus you can get right down to 1% without issues with good lights.
Leading & trailing edge dimming basically chops the AC sign wave at the beginning or end and a lot of lights do not work well with this.

- Cost to Dim
Up front may seem a little more because of the different lights required but overall cost per circuit can be as low as £20 (plus fittings).

 

When linking any of the above to a decent control or automation system (such as Loxone, Fibaro, Control4 etc) the benefits become clear very quickly.