Replacing Luminaires with LED downlighters

[AMEdinburgh]

Has anyone experience in doing the above. We have 6 suspended ceiling luminaires each with 4 36W T8 tubes running in our waiting room through Cat 2 louvers, 10 hours a day. I am trying to work out how many LED down-lighters would provide a similar bright environment.

Is the "running" consumption as simple as 6x4x36W or is there more to it? They have the older switch/condenser start and I believe that to be quite inefficient.

I've to weigh up the cost of the lamps against the time taken to recover the cost through decreased consumption.

I've used some Haler H2Pro 60 degree 8.5W lamps upstairs in the flat and something at that level of quality would be where I am looking.

Anyone done such a thing and/or point me to a suitable resource.

Thank you in anticipation of any helpful comments.

 

[Taylortwocities]

For brightness comparisons you have to stop thinking about watts and start thinking about lumens.

 

[big-all]

my personal observations are for pendants
if you aim for 1w =9w normal bulb you wont be far out
as in
1=9
2=18
3=27
4=36
5=45
6=54
7=63
8=72
9=81
10=90
11=99w
only listen to greater claims when you know they are correct through recommendation or personal observation

 

[Porque223]

Assuming your present arrangement gives you the 200 lux recommended for waiting rooms, try this
http://en.wikipedia.org/wiki/Luminous_efficacy
to compare light sources.

There is also color temperature and CRI to consider, and some people find that the spectrum of LEDs gives an unpleasant light.

LED lifetime is probably a max of 100K hours but their driver circuitry, a constant current source, may not last as long.

 

[AMEdinburgh]

Thank you for all replies.

Anyone else care to comment?

 

[RF Lighting]

You'll need at least one halers type downlighter per 600 x 600 tile to get to a reasonable level of illumination.

You'd be better off looking at either 600 x 600 recessed modular LED fittings which use about a half the electricity of a four tube flurescent fitting of the same size, replacing the tubes in your existing fittings with LED tubes, or if you really want downlighters, you'll need something around 200mm - 300mm diameter every other tile, and then doing the sums to work out which light source is going to be most economical or cost effective.

 

[AMEdinburgh]

Thank you RF. I was coming to the conclusion that I would need at least as many downlighters as tubes or perhaps many more. High cost and lots of time.

I had looked up the LED tubes before and they seem to be getting a little more reasonable. Time to crunch the numbers.

My tubs are 4' 36W T8s old school with a starter. How much more than the 24x36W = 864W are they likely to be consuming once on for the day?

 

[RF Lighting]

There will be a bit of inefficiency in the ballast as it gets warm in use, but only maybe 10W at the most as a guess.

I remember years ago being taught to treat 70W (6foot) tubes as a 100W load when doing load calculations to allow for inefficiencies.

 

[ban-all-sheds]

Has anyone experience in doing the above. We have 6 suspended ceiling luminaires each with 4 36W T8 tubes running in our waiting room through Cat 2 louvers, 10 hours a day. I am trying to work out how many LED down-lighters would provide a similar bright environment.

Why do you want to replace lights which are designed to light up rooms with ones which are designed to not do that?