Sunday, 2 February 2014

LED there be light!

We are changing the lighting in our main office to new LED lighting panels.

Before - all but one are fluorescent
After - all LED
To be fair, the original reason for even considering this was the geekiness of it. Kev is fitting out a workshop and, as he does, he researched lighting options and came up with LED lights and told me.

Now, I think they look cool, futuristic, and so on, but even I am not going to splash out over £1000 on new lighting without it being sensible, so I started looking in to the costs and savings.

In the main office we had 12 lights, each of which is four 36W fluorescent tubes. These each take up two 600x600mm ceiling tile spaces. What we are installing is 45W LED panels, each of which each takes only one 600x600mm ceiling tile space.

The first step was working out how many new lights we need. Can I swap one for one? So we installed one light initially to assess the results. We are quite pleased - the new lights appear, subjectively, at least as bright as the old lights, and maybe even brighter. They are also white rather than yellow.

So, 12 new panels, and power supplies. We also got some in-line connectors to make the installation simpler. The panels and power supplies work out around £105+VAT each.

Is it worth it?

Working out the payback on this is not as simple as it sounds.

There is simple power consumption, 45W vs 4x36W. This shows the new panels are around 1/3 of the power of the old. Assuming 12 hours a day, 5 days a week, 12 panels, you get around 1684kWh/year for LED and 5491kwH/year for fluorescent. A saving of 3700kwH at 15.8p is £584 a year saving. The cost of 12 panels being £1260, so payback in two years.

But then there are a number of other factors. Simple regular changing of old fluorescent tubes, and starters, and such, have costs for the parts and the staff time fitting them.

Of course, it is never as simple as it sounds. For some of the year we are heating the office, so reducing the power coming in to lights means a corresponding increase in power for heating. In fact, we use modern air-con for heating which means more that 100% efficiency from electrical power at the office converted in to heat. The waste from lights is merely 100% efficient. So we save some money by heating using air-con rather than heating using waste from lighting.

For a lot of the year, with an office full of people and computers, the air-con is cooling the office. Removing a heat source means correspondingly less cooling, and so less power used by the air-con.

This means we can multiply the power saving by some amount - the exact amount is not that easy to work out, but it could easily be another 50%.

Of course, the original calculations are based on the stated power ratings. The LED panels are 45W at DC and the mains power supply unit will have some efficiency less than 100%. On the other side, the fluorescent tubes will have reduced efficiency as they age, and additional components meaning it will use more than the rating on the actual tubes. It will be interesting to do an actual power test on these, which I may do later this week.

The people selling the LED panels do try to show some of the savings, but also seem to factor in to their examples an HMRC low energy scheme. Reading the scheme, it says it will save money. Yet it appears to simply be a 100% write down of capital on such lighting in first year. Personally I would think repairs and renewals for replacing light fittings would be first year write down anyway, but I leave such things to the accountants. The scheme, if it has any effect at all, appears to simply change which year tax is paid and not how much is paid meaning no actual savings at all. Maybe I have missed something.

That said, it is likely that overall the savings will result in a payback in 1 to 2 years, plus the lights look way cooler which is what really matters :-)

Fitting the new lights

This means removing the existing fluorescent fittings and replacing with the new LED fitting.

Removing the old fittings is a faff. For a start, you want to remove the tubes. This is a fiddle at the best of times, but if you don't do this first then you risk breaking them when removing the fitting, and having to clear up glass, and powder, and avoid breathing any mercury vapour. So don't do that.

Then you have to remove the actual fitting, push up, move to one side and drop down. Of course the wiring in the fitting will not allow you to lower the fitting far. So you have to take the front off it so you can get to the connectors (screw terminals). The front is attached by an earth lead, so that is a pain too. With two people, one holding the fitting and on on the ladder, you can manage. Of course the screw terminals are seized up, and you end up cutting the wires :-)

Finally, we chose some simple in-line wiring connectors. Fitting one of them to the wiring in the ceiling space was easy. You can fit the plug to the power supply safely on the ground level.

Of course, you will need a suspended ceiling T bar to change the double slot to two single slots. These are a bit of a fiddle, but not too hard.

The new panel goes in just like a normal ceiling tile. Push up at an angle and drop in place. It is a tad thicker and heavier but easy to lift with one hand if needed. It just slots in. You connect the power supply up, and pop a new ceiling tile in the other space.

Just properly dispose of the old fittings and tubes, and job done.

I got it down to under 10 minutes per light.

Emergency lighting

We also had a few separate emergency lights by the exits, as you do. The new lightings can have a simple in-line emergency lighting kit and battery. This meant we could replace the emergency lighting without having separate lights. The new LED panels by the door work as the main lights and the emergency lighting now. The emergency lighting comes on when the power is off, and is dimmed to about 30% to allow the battery to last longer.

LED lights at home?

Well, I was so impressed, I decided to do my study at home. The issue with that is I do not have a suspended ceiling. This meant I needed to find a way to fit these panels on a normal ceiling.

The answer, of course, a 3D printed bracket (see thingiverse for the ones I made). These fit to the ceiling, and allow the panel to be suspended from them whilst leaving room between the panel and the ceiling for the power supply and in-line connector.

Of course, in my study, I am more than happy with the lights. Nice and bright.

My son had to follow suit, and got new lights because (conveniently) a light fitting had just broken in his flat. So, in his games room (living room) he needed a new fitting.

Apparently, according to Julia, it is way too bright! You can't win, can you?

The good news is that a slightly more expensive power supply works with mains dimmers to allow the light to be dimmed. So, we have one on order. That should keep her happy.

Up side?

The cost saving is obviously an up side, and if you like, the green impact that has. They also don't appear to flicker, of if they do it is far less obvious. The colour of the light is much better (though you can choose, e.g. daylight white, etc). If you want more light in a room, they are a good way to do it without more cost.

The actual panels we got are IP66 rated! That means dust proof and high pressure water jet proof. One short of actually immersion in water (so don't light your swimming pool with them), but obviously not an issue in a bathroom!

Down side?

I think we have only seen one possible down side so far - we changed the lights in the toilets. There was not the obvious cost saving, but the lights in there were an 80W big spotlight in the middle of the room and always seemed very dim, annoyingly so. Apparently these bulbs need replacing quite often and are not cheap, so probably a cost saving just in replacement bulbs and time. The room is now very light, brilliant even. It does, however, show how well a job the cleaners do, and that is not so impressive. In the long run, this is not a down side at all, just more work for someone to keep the room clean!


Well worth it I think. Not that expensive. They look good, and ultimately save money. Very impressed.

I think, a couple of years ago, LED lighting was not there. Now, all of a sudden, it is. It has overtaken the fluorescent lighting and an obvious choice now.

We purchased from a company called TLC Direct. They are quick and efficient.


  1. We have some of these at work. Like you say they are lovely!

  2. I tried LED lights in our kitchen but it made the place look like a fish tank so my missus banned then..

  3. I keep meaning to purchase some LED bulbs for home, Even the ones for standard fittings have improved vastly over the last year or so.

  4. Your saving would be more as you need to factor in the power consumption of the control gear/ballast on top of the 36W for the tubes.

  5. Using the choice of colour balance as a reason to switch to LED lighting is bogus. It has long been possible to buy flourescent tubes in the same range of colour balances as on the TLC LED page you linked to. We have Daylight tubes at work, I have White tubes in my Kitchen, and Cool White in my bathroom. There may well be good reasons for choosing LED lighting but please don't quote colour balance.

    I've bought from TLC Direct several times and had no problems with them.

    I hope your LED lights last. There has been much discussion about LEDs not lasting anywhere near as long as they claim and the cost savings being cancelled out due to the high purchase cost and frequent replacement cycle.

    LED lights are a technology I'm watching, but not yet using myself. Please update us on how these do long term, eg. when they start to fail or the colour changes etc.

    1. I was only comparing colour with what we happen to have in the office and not the main reason to change, obviously. They do say "guaranteed 5 years" on TLC, so even if they had to be changed every 5 years they save money. They are very easy to change and I would say easier than the fluorescent tubes, and I would expect that in 5 years the replacements will have moved on and be way better still.

  6. With all due respect, I believe modern electronic-ballasted T5 fluorescent lighting is still more efficient in terms of lumens/watt for general lighting than LED is, and much cheaper!

    1. I have been trying to research this. Wikipedia suggests LED can be much better in lumens/W than T5 tubes, but perhaps not yet. We did not have T5 tubes, so changing the lights is a good idea anyway. These panels are 74 lm/W so not as good as a good T5.

    2. In my experience LED is by far the best for spotlighting applications because the reflector losses are zero. For general lighting T5 still has the edge and the colour rendering of triphosphr tubes is excellent, though the electronics that drive them can fail as with LED drivers. The fittings designed around LED tend to be pretty good. What I hate are the retrofit LED tubes... they correctly quote how much energy they save but fail to mention the huge drop in light output!

  7. TLC Actually do a flush mounting bracket kit for the LEDLite modular panels, but don't list it obviously on the website - the part code is LTMODSF (

    1. Cool, but, this is one of those rare occasions where 3D printing it is actually way cheaper, about £1.28 of plastic.

  8. I am not an electrician and don't keep up to date with the latest wiring regulations but as you had fluorescent tubes you would likely have 'C' type MCB circuit breakers which have a higher trip threshold in order to avoid trips due to their high starting current. Now that you are using LED with a lower power consumption you might wish to consider switching to a 'B' type and perhaps even a lower rating. It would give you better protection in the event one of the transformers developed a fault.

  9. Over here in Norway you can purchase direct replacement tubes with LED's.

    1. I'm unsure if they're a direct replacement - I have some LED tube samples in the garage. They're good and bright, but require all ballasts etc to be removed and a simple supply of live at one end and neutral at the other.
      I fitted one in our fishtank for a while, until I swapped it for 12v LED strips - I wasn't keen on mains voltage a couple of inches away from the water!

  10. I've had bad experiences with 12V LEDs used in vehicles - my car has two interior lights (designed to take Festoon bulbs, annoyingly of different sizes). The one in the front is fine, but in the back they keep failing after a few months's use. Sometimes the indicidual LEDs will fail one after the other over time, but the current one has taken to flashing, which is really annoying! Having a strobe light in the back whenever you open a door is a Bad Thing.
    In the back of my radio-van I replaced the 18W fluorescent tubes with sealed 12V "tubes" - they are aluminium C-section tubes with a string of LEDs facing out of the open side, all sealed to a decent IP level (no idea what!) I removed the fluorescent tubes and electronic gear, and fitted Terry clips that the LED tubes fit nicely.

    But again after a year or so of fairly intermittent use, groups of the LEDs (I think three at a time) have started to flicker and flash, and some have failed completely.

    So overall I'm unimpressed so far! Does anyone know of a supply of (nominal) 12V white LED strips that really do last longer than bulbs?