Thursday, February 28, 2013

Energy Efficient Lighting for Passive Houses

Been looking long and hard at energy efficient and sensible topologies for wiring a house or a building.
Here are the needs:
  1. Other than power outlets, we need very little energy for everything else - so why wire them with the 14ga Romex?  I'd like to see a new style of wiring for this stuff.  One that more closely reflects the realities of today - very small loads, and more demand for flexibility.
  2. Long term flexibility:  It is really nuts that we wire the whole house and then hide everything behind drywall - it makes it so hard to make adjustments and changes.  Why can't we have a wiring and control scheme that is modular, flexible, and not expensive?
  3. Every CFL or LED light works on voltages not related to household voltages of 120 or 240V.  All these silly LED lights we buy that fit into regular 115V sockets come with power supplies built-in.  While the bulbs can last 50,000 hrs, the power supplies die after 2000 or whatever.  Why not have a central LED light control/power supply to distribute low voltage to our lights and a host of other things like USB charging jacks, clocks, etc.
  4. We need some low voltage lights for our exposed beam ceiling.  Ever notice the exposed beam ceilings in magazines?  Most of them don't seem to have effective solutions for their lighting.  That's because there is no joist space for them to hide pot lights or wiring or electrical boxes.  A lot of times you see the light is run using a metal conduit (EMT) along the joist, and then to chandelier.  These days I always look for this when I see exposed beam ceilings in magazines.  This can be a vexing problem.  Our solution is to use low voltage (hence few electrical code issues).  The wire is small, and we hope to bury it above the plywood subfloor - this should be easy because we are looking at adding acoustic layers to the subfloor top side anyway (another vexing issue).  Then each wire will enter a surface mounted, hopefully very small light fixture  - something like an under-the-cabinet light.  The trick is finding lights like this that are small, beautiful, and give off tons of light on very little power.
Well, it looks like Lumencache is a product that addresses most of these needs, if not all.  Other than the duplex power outlets, everything is wired with CAT5 ethernet cable.  All devices are wired with home-runs to a central box.  This means every light and every switch, and every other point wired with CAT5 is a potential data node.  It also means the house's wiring is highly flexible and adaptable to future changes - 3-way wiring is done in the central cabinet, rather than in the walls.  A switch can control any light, and this can be changed, and it can control any number of lights, or it can control something other than lights. A light fixture can be changed to be (theoretically for now - not sure if any product yet exists) a smoke alarm, or it can be both, or perhaps a motion sensor with light, or a WiFi Hotspot....

The possibilities are endless.  That is why I am wiring the house with CAT5 instead of Romex.
We will be having CAT5 at every window opening, every door, every light fixture, every switch, and every thermostat, HVAC component, sensor, etc.  In addition, every data point and telephone point - the data and lighting use the same wire, after all.  Sometimes 2.  This makes it all so simple, and I would say very future friendly.

The only thing which I might wire with different cable is the in-wall speakers.  Ethernet connected speakers might be OK, but from what I hear, not quite that good as yet, so we'll probably wire them with 18gauge or something like that.

There are other developments in the home automation field which are exciting.  OpenHAB is an open-source software framework for home and building automation.  Just appeared on the internet last year.  I hope everyone who makes automation gear pays attention to that standard....
These days, the way to go seems to be to control the house with a small PC, powered by an atom processor.  These are inexpensive and consume very little energy - something like the EEEBox 1033.  On this you can run a home automation software like Mcontrol V3.  Only $170 or so online.  Apparently very open and has drivers for hundreds of different protocols so can connect to and talk to virtually everything from your smartphone.


  1. Thank you for sharing your research and thoughts on effective LED lighting solutions. One issue you don't address is cost. Have you any data yet?

    The Lumencache FAQ indicates that the installed cost of their system is essentially the same as the cost of 110V LED systems from sources such as Lutron, which I recall as being expensive. Furthermore, it is not clear whether Lumencache's statement includes savings that acrue from not having to install the 110V wiring. If it does, then in reality it is very expensive.


  2. As far as I know, the costs are compared to wiring the house with Lumencache and Cats instead of the regular 110V romex configuration.
    To me, one gets so much more with Lumencache that this is a no-brainer for new construction. Why would I go with the old style which has very little if any flexibility, no central control, is much less efficient even with LED fixtures, and has little if any potential for adding data/sensing to the lines in future?
    I'll update on costs when they become more clear.

    1. Your strategic logic is clear. But when budgets get tight other forces come into play. I look forward to your update. Many thanks!

  3. At 2012 Home Show GL-Lighting Tech Inc, of Markham, had warm white powerful LED discs which use 12vt and install similar to pot-lights but are only a tad thicker than the drywall ceiling. A good number of them can be paralleled onto one wire, but be mindful of wire and PSU's load capacity. Lights were under $20. each. Nice looking too plain gloss white surrounds. I plan to use in basement retrofitting from tube flourescents. Dimmable. Watch out that RF of remote doesn't crosstalk with same system installed upstairs as it may emit through floors. You might consider Cat5-e and install it so it can be pulled out while pulling in a replacement as the tech improves. I wonder could such systems transmit data as they are diodes...

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