House light replacements

[pumphouse]

Our existing house lighting system uses an auto-dimmer with push-button control panels (Up/stop/down) to control about 8 pendant light fittings that have R80 B22 spot reflector incandescent lamps in them. They work very nicely and have a great quality of light for their purpose.

 

Our financial controller is on a drive to change everything to low-energy/LED equivalents, so is challenging us just buying more R80s to replace the blown ones.

 

I have concerns about finding an LED or CFL equivalent that will both work with our autodimmer and provide the correct quality of light - good even diffuse spread, and relatively low colour temperature to provide a 'warm' feel to the auditorium, LEDs in my experience produce a much less diffuse light, and even the 'warm white' lamps are still considerably higher colour temperature than incandescent. CFLs often don't dim down to zero very well.

 

Has anyone else done anything similar and found a good LED or CFL source for this application you could point me at?

 

Thanks and regards,

 

Jason

[Junior8]

At a guess I'd reckon given the current price diferential there would be little overall saving at least taking only energy consumption into account. Like for like LED replacements would cost around twelve times as much I should think. Add in the value of your time researching the alternatives and I'd guess there were easier savings to be made!

[musht]

Halogen R80`s will get you about 30% power saving with no loss in light or dimming quality.

[Jivemaster]

Well I've just been to an event where the LED lighting strobed badly at less than 100%. SO if you want LEDs then plan on buying a proper set with the proper dimmers, and get them demonstrated in situ FIRST. Also always buy spares up front and hide them in the technical spaces. SO FAR there is little model continuity. Once that wholesale container is empty the next one will be about 100 mods away from original with a different dim curve and a different colour.

 

Currently no domestic lamp dims like a filament lamp.

[timsabre]

You would need to use a DALI system to do this, or GDS arcsystem also works well but is expensive.

As said above no LED or CFL lamps dim properly.

Hull City Council has recently refitted all the house lights in the Hull City Hall with LED lamps and (apart from the unfortunate choice of cool white which makes it look like a giant sports hall) they now snap on and off rather than fading nicely, with the occasional strobing for variety - horrible. Curiously in the council owned theatre nearby they have done the job properly and fitted Arcsystem fixtures, which you wouldn't know were LED, it looks and dims just like tungsten.

[Jivemaster]

One of the things I LIKE about filament lamps is that they dim to a warm colour, dimmed daylight looks gloomy, dimmed "warm white" (sort of 2600K ish) looks warm and inviting. There is some science behind using low colour temperature light in the evening because it prepares the brain for sleep in a way that dim daylight (5600K) does not.

[Don Allen]

Get your financial controller to read this article on the Sydney Opera House House Light Conversion and he will buy you several cartons of halogen R80's. The LED conversion worked very well but is not cheap.

[adamharman]

If anybody does find LED lamps (to replace filament lamps in a domestic situation) that dim properly on standard dimmers I'd be very interested.

 

5 years ago I wouldn't use LED at all, it wasn't very bright, the colour temperature was horrible, it was expensive, and it couldn't be dimmed. Now you can get something for a few quid that looks great and I use loads where they're just switched on/off but I've yet to find one that dims nicely. The "dimmable" ones are improving but still not good below 50%. Maybe in another 5 years.....

[timsabre]

The "dimmable" ones are improving but still not good below 50%. Maybe in another 5 years.....

 

I don't think it will ever be possible in a replacement lamp. You need some power to run the driver electronics and with a dimmer set below 25% there isn't enough.

I could see a solution where you replace the dimmer as well with one that talks digitally to the lamp, or something like that.

[Jivemaster]

LEDs work, LEDs dim with the right control BUT done as a cheap install expect to get odd colour rendering, odd dimming, occasional pseudo random strobing and a constant colour temperature across a dim. Done well no-one knows it's LED only the accountants care because long term it's cheaper to run, Don't think it's cheap quick or easy to install right.

[timsabre]

Really if we are discussing LED replacement lamps on mains dimmers as the op was suggesting, you cannot do 0-100% dimming with any dimmer, there's always a big snap at the bottom.

If we get away from that into 10v control or dali or wireless then it can be done well.

[itiba]

Do you have separate work lights for the auditorium or do you just use house lights? You could consider putting a couple of cheap nasty led flood lights somewhere for cleaners etc to use and switch over to the warm tungsten units for show time

[adamharman]

I don't think it will ever be possible in a replacement lamp. You need some power to run the driver electronics and with a dimmer set below 25% there isn't enough.

My electronics knowledge is fairly basic, but the electronics need a tiny amount of power and the LED only a few watts at full brightness so much less when dimmed. I would have thought charging a capacitor from the dimmer would provide enough even at low levels to acheive that? Some means of sensing the input waveform and translating that to intensity of the LED shouldn't be too difficult to achieve. Obviously it will cost more than the non dimmable ones but not enough to wipe out the savings in reduced power consumption. The change in colour temperature at reduced levels that filament lamps give is clearly never going to be achieved with a single chip LED but I could live with that if it dimmed properly.

[timsabre]

Quite a few LED manufacturers are now offering white LEDs which have an additional red die to allow the colour temperature to track dimmed tungsten (with a suitable driver).

For example Ledengin luxitune

 

Some of the premium brands have this feature in their LED replacement lamps: Sylvania Sunset Effect

(sorry this is a link to amazon.com)

 

However running the driver at low dim levels does not work - partly the problem is due to classic wallplate dimmers being rubbish and unstable at low levels. If you can put a 60W lamp on them too then everything works much better, but you can't. The only good solution I've seen replaces the dimmer with just a potentiometer which is attached to a 0-10V driver, but obviously this only works if the driver is separate to the LED.

[Tomo]

You would need to use a DALI system to do this

DALI is not suitable for theatrical houselights.

The dimming curve that DALI specifies is not what you expect, and I've never seen a DALI luminaire that actually fades both down to and up from zero - even though it should be possible.

 

I've seen many theatres fit DALI houselights, and they were all disappointed.

 

It's quite difficult to get LEDs to fade well near the bottom end, and as it's not necessary for general-purpose lighting these types of luminaire just don't try.

 

As previously mentioned, mains dimmed LED does not dim to and from zero. This is due to physics and manufacturing tolerances.

- You can't power the electronics when they're off!

 

The only LEDs suitable for houselights are the ones that have been specifically designed for theatrical use.

Most of them are DMX controlled, some are 0-10V or other analogue.

 

The GDS Arcsystem is excellent, I know of several venues with that. There's a few other really good systems, though most are more difficult to retrofit as they need the

 

If you want a quick and efficacious way of saving energy, then use Halogen capsule lamps for production houselighting, and fit some HID or LED floods for maintenance and cleaning.

- HID floods are more efficacious, but LED is instant-on which tends to result in them being used more.