Changing the colour temperature of LED lighting in the evening

[Falesh]

During the day I like a colour temperature of about 6000-6500K, but I would like to change it to 3000K in the evening to help me get to sleep. Is there a way to do this economically or do I need to buy expensive bulbs/double the number of lights in the room and switch between them?

[Roundtuit]

Not sure about daytime - I only use mine when it's dark - but I've varied the temperature around the house, and within the kitchen; half 6500k (working area) and half 4000k (kitchen table area) both on dimmers.  In the evening watching the tv, ceiling lights go off, and lamps come on (on a 3 amp circuit wired to a wall switch like some others on here have done), so I can vary the colour if I want.

 

Is it really temperature that's the issue, or brightness?  Dimmers might sort out brighness, but the only way I've seen to alter colour temperature is with colour-changing led strips.  Doubling up your lights doesn't sound aesthetically pleasing.

[Falesh]

It's the colour temperature primarily due to its affect on the circadian rhythm. I'm not sure whether the brightness of a light has the same impact as colour temperature does, I should look into that. This is for one room; I spend the vast majority of my time in my bedroom/office.

Edited March 11, 2020 by Falesh

[PeterW]

What I would do is use two different light sources. I would use spot / panel task lighting at a 6000k setting for the day, fitted to give coverage across the work area, and then use a 2500/3000k LED strip in a cove trim/cover around the edge of the area to give a low level light for late evening.

 

Neither are expensive, and both are easily controlled.

[dpmiller]

Local B&Q recently clear some 2-temperature bulbs for a few quid. Switch on as warm white 35W tungsten equivalent, toggle the light switch and they're 60W equiv cool white.

[joth]

In daytime you need more primary lighting (direct, overhead e.g. downlighters) but in evening secondary/indirect lighting comes more into its own, so +1 to @PeterW's approach of using different temperatures in different lights.

Another option we're looking into is dimmable LED bulbs that change temperature as they dim. There was a recent thread on this suggesting IKEA bulbs. Worth a look, very price effective and no extra control complexity needed. 

 

Last resort is bulbs that use Bluetooth app to adjust temperature or dedicated Dali fittings that have fully adjustable temperature. They're all are too fiddly or expensive (or both) for me to consider, but a colleague recently redid their whole house with temperature adjustable DALI fittings (controlled from Gira server and KNX) and love it. 

Edited March 12, 2020 by joth

[Falesh]

I like the idea of the strip for the evening lights. Thanks for the ideas.

[Dreadnaught]

My tuppence on this subject.

 

Smart lighting is currently developing at a huge speed. Strong rumours about Apple suggest in their next OS upgrade, scheduled for release to the public in the autumn, will include a feature to change the visible temperature of smart lights throughout the day as a standard feature (in Apple HomeKit, so called "Night Shift" for lights).

 

Combined with this, as has been mentioned on BH before, there are initiatives to dispense with those little connected boxes needed to control smart lights (Project Connected Home over IP) which is supported by all the big technology companies, even including Philips lighting and Ikea.

 

Thus within a year or two I think it will be cheaper and much easier to have lights that change their colour temperature throughout the day.

 

In my case, with an Apple HomeKit home that works reliably combined and with a bunch of Philips Hue bulbs all running from HomeKit (not controlled from Philips own app), I wrote some routines using Apple's Shortucts app to make the temperature change. I works flawlessly. But I do look forward to it becoming a standard OS feature in the autumn.

 

(Before others reply, I know that here on BuildHub some prefer not have any outgoing connections to the cloud for smart devices. My own view is that the privacy-first approach taken by Apple and the encryption levels inherent in Apple HomeKit are sufficient to allay such fears. Others may disagree.)

 

Just my tuppence.

 

Edited March 12, 2020 by Dreadnaught

[Dan F]

@Falesh Yes there is a way.  A number of manufactuers sell fittings with "tunable white" LED's that allow the color temperature to be adjusted between 2700K and 6500K.  You'll need a suitable control system to "tune" them though.  I plan to look at these, but integrating them with Loxone is a challenge given the Loxone DALI extension does not support DT8.

 

Other options are:

- "Warm dimming".  These typically have a temperature of 2700K, but reduce to 1800K as they as dimmed, and are simpler to control.

- Have main lighting at a high daylight temperature, and secondary lights for warmer more indirect evening light.

[joth]

15 hours ago, Dan Feist said:

  I plan to look at these, but integrating them with Loxone is a challenge given the Loxone DALI extension does not support DT8.

 

Do you have any tunable white DALI LED modules?

 

I have a Merten KNX->DALI gateway which works OK with Loxone, after a fashion, and AIAUI in theory supports DT8 but I don't have any drivers/modules that support it to actually test out.

 

btw I've mostly decided against the DALI because of the costs and additional wiring complexity, so will post up the bits I have for sale at some point.

 

[Dan F]

33 minutes ago, joth said:

Do you have any tunable white DALI LED modules?

 

No, but our interior designer is strongly recommending Iguzzini for lighting.  Most Iguzzini fittings support DALI and tunable white.  Not looked at the relative prices yet though. 

 

Quote

I have a Merten KNX->DALI gateway which works OK with Loxone, after a fashion, and AIAUI in theory supports DT8 but I don't have any drivers/modules that support it to actually test out.

 

Doesn't this means you need Loxone KNX extension + KNX->DALI Gateway?  Another option I looked at is DALI 4Net (Lunatone) but that requires fairly complex modbus integration with Loxone (See: https://www.loxforum.com/forum/hardware-zubehör-sensorik/211535-dali4net-via-modbus-tcp)

 

Quote

btw I've mostly decided against the DALI because of the costs and additional wiring complexity, sowill post up the bits I have for sale at some point.

 

Have you already decided on Loxone? What do you plan to use instead of DALI for lighting?  I wanted to try any find something low-voltage or PoE, but nothing really out there at all for the residential market.

 

Edited April 6, 2020 by Dan Feist

[joth]

3 hours ago, Dan Feist said:

 

Doesn't this means you need Loxone KNX extension + KNX->DALI Gateway? 

 

I've got the older Loxone miniserver with KNX interface built in, so only need the one gateway

 

3 hours ago, Dan Feist said:

Have you already decided on Loxone? What do you plan to use instead of DALI for lighting?

 

I was 95% decided on Loxone, but the recent (predictable) change in their online shop, locking it down for partner companies only, no retail sales, has given me cold feet.  I already have most of what I need, basically everything except a couple more Touch tree switches, so might keep with them. The alternative is MDT KNX switches, and either use the Loxone purely as KNX->DMX gateway or buy a dedicated gateway.

I have 30 channels of DMX triac dimmers from AliExpress,  which is a very straight forward solution and seems to work with all the mains dimmable LEDs (GU10 etc) I've thrown at it.

 

 

[Dan F]

9 hours ago, joth said:

I was 95% decided on Loxone, but the recent (predictable) change in their online shop, locking it down for partner companies only, no retail sales, has given me cold feet.  I already have most of what I need, basically everything except a couple more Touch tree switches, so might keep with them.

 

There are a number of partners that are willing to resell...  I'm getting some quotes for Loxone install, but if prices are high.. will buy parts from reseller and DIY.  Might end up using KNX for some things, but still like the idea of Loxone as simpler/central control.

[Dan F]

On 06/04/2020 at 10:36, joth said:

I have a Merten KNX->DALI gateway which works OK with Loxone, after a fashion, and AIAUI in theory supports DT8 but I don't have any drivers/modules that support it to actually test out.

 

Loxone just added DALI DT8 support, so you can now change color temperature of any DALI fittings that support "tuneable white" without any intermediate hardware in theory.

[joth]

16 hours ago, Dan Feist said:

Loxone just added DALI DT8 support, so you can now change color temperature of any DALI fittings that support "tuneable white" without any intermediate hardware in theory.

... except their (£450) DALI extension - presumably if only works via that, not KNX. I see they updated the DALI extension data sheet last month (but doesn't mention DT8), do you know if it's a new HW version?

(just asking out of curiosity so not urgent)

[Dan F]

You are right yes, still needs DALI extension, just no additional KNX bits or the KNX->DALI/Modbus->DALI extension which I'd been looking at and seems very complex.

 

Change is software only it seems. They've also added a daylight responsive function block. See https://youtu.be/JdIc4OcwvlI?t=1086

 

Edited May 5, 2020 by Dan Feist