LED Downlighting with Dimmers

[wildtangent]

Hi all

I'm on a quest to reduce my electric bills, and one of the bigger ones is definitely going to be switching my house over to LED bulbs. On that note I have a few questions. I have had a look about and want to make sure I get current info so bear with me if some of these questions have been answered before

Currently I have 34 halogen downlighters in my flat. They are all AC 12V MR16 recess downlight sets made by B&Q (input 240V, output 12V, Max 35W).

I would like to replace the ones in the hallway (3) and kitchen (4) with current-tech warm LEDs with a wide beam (its a bit dim in the corners of the rooms due to the directional nature of the downlighters).

I would like to replace the ones in the bedroom (9), living area (12) and bathroom (6) with DIMMMABLE current-tech warm LEDs with a wide beam. The living area should be split into 2 separately dimmable zones on the same switch plate, one of 9 and one of 3 lights (this is currently how the switch plate is now only without the dimmer).


So, some questions!

1. Dimmable LEDs range from about £7 each up to £30. That's a big difference when replacing a 20+ of bulbs at once. What's the difference really both in terms of light quality, longevity and power efficiency? What are the benchmarks I can use?

2. I know need a trailing edge dimmer switch for LED bulbs, but what Amp rating would I need for each dimmer switch based on the aforementioned arrays.

3. Beam angle seems to range from very narrow (around 24-36 degrees) (e.g. Philips Master 7w up to 120 degrees (e.g Lumilife 4w MR16). A wider beam seems more desirable but are there any negatives? Also the Lumilife, are they good bulbs to buy?

4. I've noticed that most of my halogens are not in a fire rated casing. I read that as I own a (basement) flat, this is advisable. Advise?

Think that's enough to be getting started with. Thanks for any/all assistance!

 

[PrenticeBoyofDerry]

1. Dimmable LEDs range from about £7 each up to £30. That's a big difference when replacing a 20+ of bulbs at once. What's the difference really both in terms of light quality, longevity and power efficiency? What are the benchmarks I can use?

The price in general will be down to quality of the component/components and the safety standards of the fitting Some units will come with all the components integrated, such as the unit can/fitting, LED driver and the lamp. There will also be other things to consider such as if the fitting is designed to prevent the spread of fire, moisture and sound. This all ends up costing a little extra to those cheapo/poor quality ones kicking around at B&Q/Wickes/Homebase/Screwfix/Toolstation/and many other stockists, where they are probably not specified against fire, moisture, sound and you will need to purchase drivers and lamps
The quality ones often come with 7-10 year warranty

2. I know need a trailing edge dimmer switch for LED bulbs, but what Amp rating would I need for each dimmer switch based on the aforementioned arrays.

The amp/current rating would really be determined by your supply current as it really should be greater than the device protecting the light circuit, so for example if you have a 6A breaker at the consumer unit, then the switch plate require to be equal or higher than that, most switch plates are rated at 10A though.
But I guess you are asking really about the output rating of the switch?
You need to add up the total value of the load (lamp watts) that each switch will be switching, the dimmer requires to be rated higher than that load
So if you have say 10 LED lamps rated at 10W on the one dimmer switch then that dimmer needs to be able to deal with a load of 10 lamps X 10W =100W

3. Beam angle seems to range from very narrow (around 24-36 degrees) (e.g. Philips Master 7w up to 120 degrees (e.g Lumilife 4w MR16). A wider beam seems more desirable but are there any negatives? Also the Lumilife, are they good bulbs to buy?

The beam angle would really be determined by personal choice and what spread of light you require in certain situations, never used lumilife so cannot comment, normally use Aurora never had a problem with them, so happy to stick on that

4. I've noticed that most of my halogens are not in a fire rated casing. I read that as I own a (basement) flat, this is advisable. Advise?

You will need to access the risk, I generally put fire rated units where ever there is an habitable space above, but that does not mean that there is a requirement to do so, have look at this bit of literature, may help: http://books.google.co.uk/books?id=...epage&q=fire compartments wiring regs&f=false

 

[46philh]

Used these below and cannot fault them.....

Yes they cost but last a long time and massive saving in elect cost.

Doubt you find a good mr16 12v Dimmable one though.


http://www.simplyled.co.uk/led-spotlights/mr16-led-bulbs-12v/mr16-led-nxtgen-series-iii-non-dim.html