Green Building Forum - LED savings Tue, 19 Dec 2023 05:30:39 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284437#Comment_284437 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284437#Comment_284437 Sat, 07 Nov 2020 15:56:19 +0000 tony
Unusually two regularly use spaces one a gym and the other a art area both remote from the other buildings and both with radiant electric heating.

In both cases I rejected the winter savings on heating, can you see why?

I have a very interesting semantic point on LED and it is true too --  when the energy rating of lighting is reduced less heat goes into the building as lost heat from lighting (saved on electricity bill) BUT in the heating season this heat was reducing the demand from the heating system and so not all of the savings attributed to LED are genuinely available, there is often a cost saving but it will be the difference in cost between electrically produced heat and oil or lpg heat which is delivered cheaper per kWh output.
In the space with electric radiant heating there is no saving for changing to LED !!!!!]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284442#Comment_284442 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284442#Comment_284442 Sat, 07 Nov 2020 16:47:28 +0000 Mike1 LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284444#Comment_284444 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284444#Comment_284444 Sat, 07 Nov 2020 18:14:08 +0000 tony LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284452#Comment_284452 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284452#Comment_284452 Sat, 07 Nov 2020 21:34:24 +0000 muddy LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284455#Comment_284455 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284455#Comment_284455 Sat, 07 Nov 2020 21:56:24 +0000 tony
My hobby is reducing energy use 🙂]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284456#Comment_284456 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284456#Comment_284456 Sun, 08 Nov 2020 00:05:11 +0000 WillInAberdeen
The Radiant heating in the gym is maybe chosen to get the heat downwards, to where the people are, without needing to heat the whole building. Wouldn't heat from incandescent light fittings just rise up to the roof 30 feet above everyone's head?]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284459#Comment_284459 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284459#Comment_284459 Sun, 08 Nov 2020 07:59:30 +0000 tony LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284479#Comment_284479 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284479#Comment_284479 Sun, 08 Nov 2020 22:53:15 +0000 Jeff B LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284484#Comment_284484 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284484#Comment_284484 Mon, 09 Nov 2020 10:54:03 +0000 SimonD Posted By: Jeff BI have never considered radiant heating. Is it any good? It's still electric at the end of the day so I assume quite expensive to use?

I installed an IR panel that looks just like a whiteboard in our temporary garden office. It's a 580W version I think. It's definitely more efficient than a fan heater or oil radiator, but I don't think I'd consider installing them throughout my home. The warmth feels lovely mind you as it's like having gentle sunshine on your back while working away. My wife loves it.

I'm quite interested in the discussion on heat/light energy consumption as I'm also looking to design our lighting plan. I like the fact that LEDs save energy but I'm less enthused by their application. I don't generally like the quality of light emitted from them where with many versions I've experienced produce too much glare for my liking. Perhaps that's just down to poor specification and installation design patterns?]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284488#Comment_284488 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284488#Comment_284488 Mon, 09 Nov 2020 13:00:47 +0000 Jeff B
Re LEDs. I think it's a case of "horses for courses". We prefer the warm white versions in the living rooms/bedrooms but the cool white type in the kitchen, workshop etc where a brighter light is needed. I must admit I do tend to buy bulbs with a higher output than is probably necessary because the wattage is so low anyway!]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284490#Comment_284490 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284490#Comment_284490 Mon, 09 Nov 2020 14:50:26 +0000 tony
Low temperature spectrum for me everywhere

Should really calculate lumens, and beware of glare and over specifying how many needed - too common

Don’t get me going on street lighting which will all have to get changed to very low temp spectrum 2400-3000K to protect wildlife eventually.]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284491#Comment_284491 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284491#Comment_284491 Mon, 09 Nov 2020 17:58:35 +0000 Simon Still Posted By: SimonD
I don't generally like the quality of light emitted from them where with many versions I've experienced produce too much glare for my liking. Perhaps that's just down to poor specification and installation design patterns?


I think that's completely poor specification and installation design - most likely the terrible trend for electricians/builders/whoever to fit a huge number of fixed recessed spotlights in the ceiling.

I bought a few books and read up before designing our lighting. We've got LED spots everywhere but they are all adjustable - the only ones that are set straight down are in the hall. If you use them to light the walls and bounce the light back into the room (light objects/artworks etc) the lights much more interesting and pleasant.

You don't actually want/need many rooms super bright or evenly lit (except maybe when cleaning!).

Led bulb replacements are really good now - Phillips the best I've found.
All our lighting is 2700k colour temperature (except the workshop and utility room which have daylight fluro tubes)

If I was doing it again I'd probably have slightly cooler light in the bathrooms and kitchen. The advice I've seen since is that you want a cooler temp (ie higher K number) where you're trying to supplement daylight rather than add mood when its dark]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284493#Comment_284493 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284493#Comment_284493 Mon, 09 Nov 2020 18:50:55 +0000 tony LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284494#Comment_284494 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284494#Comment_284494 Mon, 09 Nov 2020 19:26:47 +0000 Victorianeco
Eg. How many lumens per room/height of ceiling or m2 etc?

We have led filaments on chandeliers in the hallway (2no x 5 bulbs) and I'd like spots, can you get chandeliers with spots? The missus is insistent on being chandeliers but lighting is an area of interest to me]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284498#Comment_284498 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284498#Comment_284498 Mon, 09 Nov 2020 22:36:31 +0000 Jeff B LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284500#Comment_284500 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284500#Comment_284500 Tue, 10 Nov 2020 08:20:52 +0000 tony LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284602#Comment_284602 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284602#Comment_284602 Sat, 14 Nov 2020 09:48:08 +0000 goodevans Posted By: Jeff BI have never considered radiant heating. Is it any good? It's still electric at the end of the day so I assume quite expensive to use? sorry, late to the discussion. All low temperature heating could be considered to be radiant heating - the lower the temperature diff to the room the less convection is a factor. Of course heating from above at almost any temperature is primarily radiant.

Tony,
We have installed recessed led lights throughout the house - mainly for their unobtrusive look (white bezel on a white ceiling) and our air tightness layer is well away from the plasterboard (at the rafter level) so not a problem for us. Being unfashionable I usually end up buying/choosing stuff just as it goes out of fashion - oh well.]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284614#Comment_284614 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284614#Comment_284614 Sat, 14 Nov 2020 16:41:09 +0000 Simon Still Posted By: tonyjust an unfortunate fad, pool at general lighting, a disaster for air tightness (even in g/f ceilings), I would love to see the back of them

I respectfully completely disagree. Airtightness shouldn't be at the plasterboard/internal ceiling level. The further out in the envelope the better. Recessed spots are a good way to light a room - way better than the classic UK solution of a single central ceiling rose which is utterly useless with a typical 2.4m ceiling when I'm 195cm tall...

However, they need to be located with a bit of thought (not just a grid pointing straight down) and to be able to be directed. Wall mounted (or floor mounted) uplights good as well, some table lamps wired into 5A sockets linked to the room light switches too.

In terms of design I bought https://www.amazon.co.uk/Lighting-Bible-Ideas-Every-Room/dp/1845433572 and it was pretty good.

How many Lumens light you need is more difficult and I'm still not sure but if you're using bulbs that can be swapped out then it is something you can change fairly cheaply.

(on the other hand I'm cursing the expensive wall mounted beside lights we bought. non replaceable LED with supposedly 60k hours life - even if they were on 4 hours a day that would be 40 years and the reality is nothing like that much. One now has an intermittent flicker. I'm guessing it's the driver thats' failed rather than the LED (anyone think differently?) so I *might* be able to source something of the right size to fit within the lamp case but I bet it's not going to be easy. For 99% of owners it would be in the bin.]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284622#Comment_284622 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284622#Comment_284622 Sun, 15 Nov 2020 12:26:08 +0000 revor LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284634#Comment_284634 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284634#Comment_284634 Sun, 15 Nov 2020 17:35:57 +0000 djh Posted By: Simon StillAirtightness shouldn't be at the plasterboard/internal ceiling level.
I think Tony was thinking of existing houses rather than the design of new ones where you have control. The space above the ceiling is very often a problem area.]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284635#Comment_284635 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284635#Comment_284635 Sun, 15 Nov 2020 17:37:34 +0000 djh Posted By: revorCollingwood
Reassuringly expensive :cool:

I bought John Lewis cheapest own brand fittings. :bigsmile:]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284733#Comment_284733 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284733#Comment_284733 Tue, 17 Nov 2020 13:51:25 +0000 CWatters Posted By: VictorianecoSimon: Can you share the books you read up on? Or can you give a bit more insight into light design?

Eg. How many lumens per room/height of ceiling or m2 etc?



That depends on the room and its usage. If it helps there are comparisons such as..

Lumens Incandescent light bulb (Fluorescent)
375 lm 25 W (6.23 W)
600 lm 40 W (10 W)
900 lm 60 W (15 W)
1125 lm 75 W (18.75 W)
1500 lm 100 W (25 W)
2250 lm 150 W (37.5 W)
3000 lm 200 W (50 W)

Some thoughts on spots/downlights..

If you are looking at replacing existing downlights then be aware that a 50W 230V GU10 puts out less light than a 50W 12V MR16. I think in a kitchen they recommend a 0.9-1m spacing for 50W 230V GU10 and 1.2-1.3m spacing for 50W 12V MR16 (its a different spacing anyway).

So with that in mind I reckon a 450 lumen LED is equivalent to a 50W 230V GU10 and I've made that swap. If you are replacing 50W 12V MR16 on the wider spacing I think you need to look for nearer 550 Lumen LED if you can get them. Elsewhere that comparison chart seems to work ok.


The beam angle from downlight bulbs also varies. Personally on a grid like you have in a kitchen I prefer wide angle (120 degrees) over the more common 35 degree LEDs. You get a more even light with fewer shadows but a bit more glare. For some reason wider angle are harder to find.

There is a vast array of LED "chandeliers" (aka ceiling lights) these days..
https://www.google.com/search?q=modern+downlight+chandelier+LED&tbm=isch&ved=2ahUKEwiJmsSc3IntAhUC0xoKHd8uA0gQ2-cCegQIABAA&oq=modern+downlight+chandelier+LED&gs_lcp=CgNpbWcQA1CGkgJYzZsCYPmfAmgAcAB4AIABQ4gB8gGSAQE0mAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=6tSzX4n9BYKma9_djMAE&bih=833&biw=1461]]> LED savings http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284734#Comment_284734 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16783&Focus=284734#Comment_284734 Tue, 17 Nov 2020 13:54:00 +0000 CWatters
https://mountlighting.co.uk/technical/cibse-recommended-lighting-levels/

1 LUX = 1 Lumen per square meter.

Technically its not as simple as multiplying the required lux by the floor area because light gets reflected. Bulbs also don't emit light equally in all directions and other issues. However lets try that..

The table says for a kitchen you need say 300 Lux. If your kitchen is say 4m * 4m that's 16sqm so you might need lights that generate 16 * 300 lux = 4,800 Lumens. That could be a 3 * 3 = 9 grid of downlights each would need to be 4800/9 = 533 Lumens.

Earlier I said I was happy with LEDs around 450 Lumens so I guess this method may overestimate slightly.

Apologies to any real lighting engineers.]]>