Fluorescent tubes efficiency

[CChris]

Hi,

Ive just had an energy efficiency review/certificate done on a building I own, and one of the items noted on the improvements is the replacement of 38mm T12 tubes with 26mm T8 tubes.

However when Ive taken a light down myself to check this, Ive found they are Phillips PL-L, not T12.

Ive done a bit of a google but cant find the anwer, but it looks like a PL-L 4 pin fitting, is just the equivalent of having two seperate T8 tubes.

Has the inspector made a mistake here or can I swap out these PL-L's for T8's and is there as much benefit as the stated "swap T12s for T8's" noted on the assesment?

Many thanks for any help.

 

[winston1]

Buerocrats don't you love them? Yes T8s are more efficient than T12s but when you consider the cost of replacing them against the energy savings it does not make financial sense. When they wear out get T8s next time. But with some high frequency control gear you can't just swap them anyway. New control gear means more money and more of the planets resources.

I can't answer re efficiency of PL'L against T8 but the cost of replacing them argument still applies.

I have 3 5ft T12s in the garage and 2 in the loft and they are staying there. I also have a box of second hand spares acquired when people foolishly swapped for T8s.

 

[CChris]

I dont think we have any T12's They all appear to be these PL-L type - and rough estimate we have about 100+ of them in this building, and the lights tend to be on most days for about 8 hours. All with 2 x 55w PL-L's in - so somewhere in the region of 11KW of lighting.

The building is in Band D for efficiency, and we are just a few points away from a C, not the end of the world, but I'd just like the report to be correct. So if we have been marked down for having T12's, when in fact we dont have them, and the PL-Ls are as efficient as the T8's (or at least more efficient than the T12's), then that may get us a few points.

 

[ban-all-sheds]

I'd just like the report to be correct.

Can't argue against that desire.

Nor against the suggestion that if they got it wrong you should not pay for it.

 

[Iggifer]

PL-L's are compact fluorescent lamps so it wouldn't just be a case of changing the tube & control gear you'd need to change them for whole new fittings. And a 55w PL-L is 541mm in length, so I don't really see how this guy got confused.

Philips do a PL-L "Energy Advantage" that is apparently as bright, but only 40W, and is Energy Rated A, don't know what your current lamps are rated as.

 

[ericmark]

From 60 lumen per watt to 100 lumen per watt they all seem to have same energy rating. I seem to remember the Phillips PL-L is rather high up lumen per watt can't really see any point in changing them.

 

[CChris]

Thanks for the replies. I'll have a chat with the assessor tomorrow and see what the explanation is.

 

[333rocky333]

2x 55w pll lamps is a common choice in 600mm x 600mm sguare modules in retail lighting, mainly as an improvement to the older 4 x 18w T8 tube fittings , so one 55watt pll lamp really replaced using 2 x 18w T8 tubes

The "T" in T8 stands for Tubular and as you know a PLL is a U shaped lamp, Your twin Pll lamps will be working off either 1 or 2 high frequency ballasts, there is no T8 "Tube" shaped lamp that will run on them ballasts or even fit in the light fitting without major rebuilding, I would of thought the only improvement from the pll lamp is Led.
With his referance to T12 could he be talking about some batten fittings in your buildings back areas rather than your main lights

From BLT website
PLL Compact 55 Watt
The Compact Fluorescent lamp is a low energy cost effective light source designed as energy saving alternative to the conventional incandescent lamp type. As this is a specialist lamp please check you have ordered to correct cap/base type when replacing failed lamps. The PLL Compact lamp is one of the most popular CFLs on the market featuring a lamp life of up to 15,000 hours (15 times that of an incandescent) and offering savings of 80% in energy usage.

The initial cost may put you off, but don’t be fooled; this lamp pays for itself 5 times over the course of its life! The PLL lamp also features superior lumen efficacy and excellent colour rendition, so you can be sure you are getting a high quality lamp ticking those all-important cost, quality, reliability, and energy efficiency boxes.

The output of the 55 Watt PLL Compact is the equivalent of a 200 watt incandescent, so is ideal for applications where a powerful; light source is required. This lamp comes in 8 different colour temperatures including Multiphosphor colour temperatures; this type of lamp offer exceptionally high colour rendition and superior efficacy and is very common in professional commercial applications.

 

[CChris]

Thanks again for the info.

The building is only office, and lighting is only in the 600x600 ceiling tile fittings. There are a few round fluorescent bulbs on the staircase and in cleaners cupboard but again these are thin and not T12.

 

[ericmark]

I, in a way, got caught out. The old 65W 5 foot fluorescent tube failed and when I went for a replacement found they were no longer made. This left me with a number of options from a complete new fitting to changing the ballast for a 58W type to fitting a LED tube.

Without checking lumen per watt I found the LED tube was 24W v 58W for the fluorescent so jumped in both feet and bought the LED replacement tube. On fitting the tube looked bright but I found I needed my glasses where I had not needed them before. So I then rather late in the day as already bought and fitted started to look at lumen output.

I could not get good figures as the fluorescent tube I was comparing with was the new 58W and although lumen values are given they are for when used with a wire wound ballast, if I was going to replace the ballast it would be a HF type. It seems all HF ballasts are not equal down I am told to if the heaters are used and if used are they turned off when it fires up, and also how good the step down transformer is. It is claimed the HF ballast uses less power, gives out up to 10% more light and extends the life of the tube by a third again. But there are no published figures. So much also depends on the tube which can have different coatings so all you can get is figures for using tube with a wire wound ballast of the correct voltage.

So figures 24W with 2400 lumen output if the existing control gear is removed for the LED tube. For the fluorescent tube 58W with 5100 lumen using a wire wound ballast. Tube life LED 30,000 hours, fluorescent 20,000 hours. If using a HF ballast it would seem the lumen would likely be 5610 lumen and hours 30,000 so looking at 96.7 lumen per watt compared with 100 lumen per watt with life the same.

As to cost LED = £17.09 and HF ballast complete with fitting and tube £16.20 also replacement cost of LED tube £17.09 and replacement cost of HF tube £3.12 so in real terms the HF fluorescent is far better than the LED replacement only way they make you think the LED is better is by reducing the output.

To get same output from the LED tube one would have to swap to twin tube version so add £31.19 for new fitting then assume you can sell the new tubes on and ballast which is unlikely so add £11.81 for empty twin fitting plus two tubes so like for like in light output LED costs £45.99 and HF costs £16.20 now we start to see things in a different light excuse the pun. The LED costs 284% more than the equivalent Fluorescent and saves 3% on power used.

I am sure some one can work out how many years to pay back, but since the replacement fluorescent tubes are that much cheaper clearly if over 4 years then they will not save, assuming a tube used all night will last 4 years. At today's prices the LED tube is a non starter in more ways than one. As well as massive increase in cost there is also the safety issue should some one try to change back to fluorescent or even put the tube in wrong way around or get a LED starter and a fluorescent starter mixed up.