House lights replacement

[pmiller056]

A question on behalf of a local community theatre...

The auditorium gets used for community hires. The tiered theatre seating is usually stored rolled away, leaving a useful flat floor space of around 5m x 15m for dance, drama classes and similar uses. Most hirers regularly use the dimmable house lights 'because it looks nicer' instead of the fluorescent working lights. This lighting is installed at a height of 5 to 6m above the floor. 1.7kW of dimmable halogen downlights costs a lot of money to run. The halogen lamps are supplied from a common 2.5kW thyristor dimmer and are switchable in 3 banks to cater for different uses of the space.

 

Are there any sensible dimmable LED options to replace the existing lighting to reduce running costs? I'm aware of the limitations of some dimmable LED systems at low (<20%) brightness levels. Depending on chosen solution, the existing thyristor dimmer does not need to be retained. Needless to say, because it is a self-funded community space, the installed cost of any replacement is a major consideration. The pay-back time based on energy savings will be a big influence on any chosen solution.

Thank you.

[sandall]

From (limited) home & local theatre experience Philips LED lamps seem to dim ok & last well; Chinese ones, particularly "special offers" don't & don't.

[Junior8]

Charge them the right hire for a start. I spent hours twenty five years ago convincing the powers that be that the hirers of our theatre space weren't covering the running costs. It got through eventually.

[A.Russell]

Junior8 is right that usage that incurs higher costs should be charged out at a higher rate. Whilst it may be hard to convince management teams/directors of this, the incandescent lamp ban (I know there are exemptions, but by now every performance space should have long term plans to replace incandescent equipment) and now the halogen lamp ban means that legacy systems have to be replaced.

 

It sounds like you/the venue are thinking along the right lines for your house lighting.

 

One of the best LED systems (with true fade to black) is GDS houselights, though quite possibly outside of your budget.

 

An alternative might be (as suggested) dimmable LED lamps but with a suitable dimmer. The sunDial quad from Artistic Licence is probably just the dimmer that you are looking for. They have custom dimming profiles available for a number of lamps and from the demos that I have seen it appears to be pretty good. Link here. Wayne at Artistic Licence is very helpful and may be able to do a demo. Failing that Stage Electrics retail them and have previously demonstrated them at PLASA and may be able to do something.

 

I have no connection to Artistic Licence or Stage Electrics, I have just seen the product. I would be interested to hear from anyone that has used the sunDial quad long term to see what they think of it over a longer period.

[richardash1981]

Most hirers regularly use the dimmable house lights 'because it looks nicer' instead of the fluorescent working lights.

 

Have you thought about fixing that instead, so that you can reasonably stop users using the house lights?

My logic is this: I doubt that the hirers actually care about the house lights being dimmable, particularly if (as you suggest) they are all on one dimmer. They use them because they are either in a different place to the fluorescent lights (and so illuminate differently), or have a markedly different colour temperature (or there is some maintenance issue with the working lights which means they flicker etc.).

 

My suggestion is you consider replacing the fluorescent tubes with (non-dim) LEDs (either whole fitting replacements with battens, or retro-fit tubes), of a colour temperature suitable for the use the space is put to, which is probably a warm white. From a reputable supplier these should be flicker-free (unlike the current tubes) and cheap to run, without being as "cold" a light as most fluorescents are by default.

 

[adam2]

What type of lighting fixtures are used, or proposed for house lights ?

 

If other circumstances permit, it can be preferable to use fixtures that take multiple lamps to give an indirect light reflected from the ceiling. Dimming tends to be imperfect near the bottom of the range. An indirect fitting tends to hide this and give visually better results.

If one lamp that is exposed to view, snaps to off at say 30% this gives a displeasing effect. If an indirect fitting contains 6 lamps, one of which snaps to off whilst the other 5 lamps dim, then this looks better. Even if all 6 lamps snap to off, but at slightly different dimmer settings, then the overall effect is not bad.

[sleah]

Houselight dimming curves.

 

I wonder how many people other than 'techs' even notice the houselight dimming curve? I doubt the audience would be aware that they snapped on or off at 5%. I think it's more important in a professional theatre to get these things right as there is greater expectation.

However in schools/community centres/am-dram it's less so. I'm sure many of us have been operating lighting for a show, nice fade to black after the final bows, then the pregnant pause and about to bring up houselights and BAM!, some helpful person puts all the flourescents on.... I've had it happen at the interval too - even pre-show :o . Audience don't seem to notice or care, but I have to hold back the expletives and politely explain that I am in control of the houselights.

Edited September 3, 2021 by sleah

[richard_cooper]

Houselight dimming curves.

 

I wonder how many people other than 'techs' even notice the houselight dimming curve? I doubt the audience would be aware that they snapped on or off at 5%. I think it's more important in a professional theatre to get these things right as there is greater expectation.

 

Interestingly I used to work in a newly built theatre that had a fluorescent dimmable house light system that claimed to dim to 1%. The ballasts claimed 1% capability but the snap off/on was still really pronounced. We did use to get a surprising number of comments about it, especially the jarring snap back on.

 

Fortunately for those of us that cared the ballasts were seriously unreliable and within a couple of years became nearly impossible to get hold of so the whole system was changed.

[Tomo]

I wonder how many people other than 'techs' even notice the houselight dimming curve? I doubt the audience would be aware that they snapped on or off at 5%. (snip)

Almost everybody notices snap-on/snap-off and popcorning, unless you can't actually get a blackout at all.

 

School shows (especially when in school halls) get a lot of slack because everyone is there for their specific darling (and they usually don't get a decent blackout anyway).

 

Way back when, I had a few 'school show' parents pass compliments on how the lighting was "so much better than last year", when the only real change was a (possibly) better blackout and actually using the proper houselights instead of the exam hall floods.

 

Punters rarely know why they don't like it, only that they didn't.

 

Anyway, for the OP:

 

First of all, try to find out why these hires are using the tungsten houselights instead of the cleaning workers.

It's very likely because they're "too harsh" (meaning too cool), or that they flicker.

 

I agree with richardash that it's worth looking into replacing the florry worklights with non-dim LED.

It may well save more energy than replacing the houselights, as workers tend to be on for far longer.

 

- If nothing else, it's going to be more difficult to buy (and dispose of!) replacement tubes in the next few years as they don't meet the Eco Design regs that came into force this year.

The specialist halogen lamps are still permitted and will still be made for many years (albeit the price will rise), but the same is not true for fluorescent tubes.

 

The other common alternative is to replace both systems with theatrical-quality dimming LEDs and use them for everything, perhaps breaking it up into more circuits so the purely decorative lamps are only used for shows.

 

Choosing something suitable depends entirely on your current houselighting and control.

- Many smaller places have simply put up a load of COB LED Par-style fixtures, others lots of LED tape with good drivers, but that's not suitable if you've got a nice chandelier!

Edited September 3, 2021 by Tomo

[pmiller056]

Thank you all for your helpful comments and suggestions.

 

The working and house lights illuminate the same useable space and are available to all auditorium users. For logistical and practical reasons it is not practical to restrict access to the inefficient house lights for specific users. The auditorium has a pitched ceiling which is the underside of the roof and is painted black, so uplighting as suggested by @adam2 is not a sensible option. Our treasurer is well clued up on the cost of heating, lighting, cleaning, maintaining and generally running different parts of our building - I'll let him/her tell the managment committee how much to charge our hirers. Energy savings will most likely end up in the capital account to pay for future 'big ticket' refurbishments and upgrades.

 

The fluorescent working lights have a higher colour temperature than the house lights which makes them look harsh and industrial in comparison. They are relatively new (<10 yrs), so they have HF electronic ballasts, are flicker free and start 'nicely'. We have noted that different users do set different brightness levels to suit their needs when using the dimmable lighting, so it is a feature that hirers want to use. If a good dimmable houselights system is installed and the operating costs are similar then I would expect the fluorescent working lights to become disused and eventually removed.

 

The GDS systems noted are very nice but well outwith our budget range. The Artistic Licence product mentioned by @A.Russell is interesting because it appears to work nicely with well-chosen commercially available 'normal' LED lamps. A benefit of this system is that it can re-use most of the existing infrastructure and wiring which will significantly reduce installation costs. We are able to acheive a very dark blackout, so from comments above, low-end 'snap on' is something that needs to be well controlled in any upgraded system. Another benefit of the AL product highlighted is that it is natively a 4 channel system, so it would be a 'drop in' replacement for our existing bank-switching arrangement.

 

Looking at @Tomo's suggestion, the houselight system is available 25/7/365, so I'd be inclined to use 'normal' household/industrial lamps. In the first instance I'm not sure about the long-term survival of leaving theatre/entertainment COB PAR fixtures powered continuously. Trying to get a compatible like-for like replacement for any failed COB PAR fixture after installation may be difficult. Changing a group of 'normal' lamps after failure will be easier and cheaper when LED lamps do fail, despite the manufacturer's promises....

 

Thank you again.

[Owain]

Is it possible to switch the fluorescents in banks/sections so there's more choice than all on / all off?

[pmiller056]

@Owain - at present, no. The fluorescent fittings are open-tube ones (no diffusers or reflectors) attached directly to the undersides of the open roof trusses (for minimum cost worklighting). They throw light everywhere, so in practice bank switching won't acheive much. I'm beginning to think that any money that could be spent improving the worklights probably would be better spent on improving the houselights, which is what people want to use.

[TomHoward]

Can I just ask, 1.7kW of house lighting would cost circa 35p/hour to run?

And even then that's at 100%, if they are dimmable it may not even be that much? Is it worth the investment to avoid or could it be better spend on reducing costs elsewhere?

 

Out of of interest what is the total power of the fluorescent light?

[adam2]

Can I just ask, 1.7kW of house lighting would cost circa 35p/hour to run?

And even then that's at 100%, if they are dimmable it may not even be that much? Is it worth the investment to avoid or could it be better spend on reducing costs elsewhere?

 

Out of of interest what is the total power of the fluorescent light?

 

35 pence an hour sounds about right, it corresponds to about 20 pence a unit which is rapidly becoming the new normal. And even if the electricity cost is less than 35 pence an hour, then the total costs including lamp replacements could easily be as reported.

 

Dimming does not save much, a lamp dimmed to 50% light output uses a lot more than 50% of ratted watts.

 

As regards the running cost of the fluorescent lighting, simply add up the lamp wattages and add up to about 2% for electronic ballasts, or about 15% for newish copper/iron ballasts, or as much as 25% for older types.

[pmiller056]

The fluorescent worklights have a total installed load of around 250W. 35p/hour doesn't sound much, but this adds up to a lot of money with too many 100's hours of running a year. The suggestions and information above from the community are useful and helpful, so the next time the managment committee are looking for suggestions to reduce operating costs, this is one that can be put to them. As energy and maintenance prices rise and the payback time becomes shorter this and similar upgrades becomes more attractive. Our mostly halogen stage lighting doesn't get used enough over a year to make replacement viable, yet....