PDA

View Full Version : Converting 120V can lights to 12V?


Lite4
09-10-2007, 08:04 PM
I looked at a house today that I am going to be lighting soon. The homeowner has about 50-60 soffit mounted recessed 120 volt can lights being used to downlight the architecture of his house. He likes the effect but is not so keen on his electric bill every month as a result of these lights. He asked about converting these cans to a 12 volt system. I have seen the 12 volt cans before, but I don't know if there is another way to do this or if it can even be done. He doesn't want to really do any additional uplighting on the house, but would rather utilize the cans if he can. His builder told him no because of nearby insulation, but I can't imagine the line voltage lights are much cooler. Any body have any thought or solutions I might entertain? Thanks for the help in advance.

Firefly Lighting
09-10-2007, 09:16 PM
Tim- Depending on the size can that is already installed (6", 8" ?) you could possibly change them out with and MR-16 can that has an integral transformer. Juno makes good ones and have ones that are rated to be against insulation. The only problem is that most of the MR cans are 3-4". Good luck

pete scalia
09-10-2007, 09:48 PM
what are you gaining by changing them out but a big materials bill. why not use a lower wattage bulb or put them on a dimmer and be done with it.

Chris J
09-10-2007, 10:00 PM
Yes, I don't understand the reasoning either. A 20w low voltage lamp will burn no more or no less energy than a 20w high voltage lamp. There is no energy savings simply because the system is low voltage. Can you not change the lamps to a lower wattage and or different style of lamp? What is currently in use at this time?

Pro-Scapes
09-10-2007, 10:05 PM
it is possible as Matt said. As chris said 20w is 20w... does he have monster 75w lights where a 35 halogen would do the trick ?

It will be rather pricey and will need to be done by an electrican. You need to find out the size of the cans and then go from there to see whats avalible. In actuality he would be cheapest to install a ground mounted system and then only turn on the downlights when entertaining and such.

Im sure the downlights are really nice.

I dont think adding a dimmer would be the answer here. If its too bright as is it might be a good start as a dimmer switch is rather inexpensive but i would feel its just a bandaid in this situation as it might drop the level of light to low.

How acessible are the cans ? can you get to them easily from the attic area ?

I hope you have a good working relationship with a great electrician on this one :)

JoeyD
09-10-2007, 11:10 PM
A Watt Is A Watt

INTEGRA Bespoke Lighting
09-10-2007, 11:43 PM
Although it is true that a watt is a watt, there is an inherent electrical efficiency in using low voltage lamps over line voltage lamps. Fact is that Low Voltage lighting produces about 33% more light per watt then line voltage lighting does. Don't believe me? Closely check out some lamp photometric charts from GE or Sylvania.

That being said, I would suggest that Tim look to using a good dimming system on the installed soffit mounted recessed fixtures OR look to some of the new, emerging LED lamp technology that is out there. I am sure you will find some appropriate PAR base LED lamps that will offer you the colour and intensity you require while significantly reducing the electrical bill the client recieving.

Changing over the fixtures or perhaps the wiring system to a Low Voltage system would be cost prohibitive.

Have a great day.

Eden Lights
09-11-2007, 12:02 AM
Although it is true that a watt is a watt, there is an inherent electrical efficiency in using low voltage lamps over line voltage lamps. Fact is that Low Voltage lighting produces about 33% more light per watt then line voltage lighting does. Don't believe me? Closely check out some lamp photometric charts.

Have a great day.

I agree a watt is a watt, if you are comparing apples to apples there is no difference. There is not inherent electrical efficiency that I know of?? Please explain? Are you studying MR's against MR's or BiPins against BiPins?

Eden Lights
09-11-2007, 12:55 AM
I agree a watt is a watt, if you are comparing apples to apples there is no difference. There is not inherent electrical efficiency that I know of?? Please explain? Are you studying MR's against MR's or BiPins against BiPins?

I was just thinking about this a little more and looking at some lamp charts and I understand what you are saying now,my comment above was wrong. I think it just pertains to the Halogen lamps due to the way that the filament is wound in a low voltage lamp and not the actual voltage? I was thinking about it from the 12 vs 120 debate and not the actual lamp vs. lamp in output lumens. I have not got much sleep since Friday, working in the mountains of Colorado and I am all messed up.

steveparrott
09-11-2007, 07:46 AM
James,

I'm a little foggy on some of the electronics, but isn't it true that using a dimmer does not diminish the load on the system. Doesn't it just clip the wave or increase resistance - both having the result that the energy is converted to heat in the dimmer? Could be wrong on this - enlighten me, please.

INTEGRA Bespoke Lighting
09-11-2007, 08:36 AM
Dimmers are widely touted and promoted by the electricity industry as an effective means by which to reduce the amount of electricity you use. Certainly some power is lost to heat inside the dimmer, but not all.

If you contact Nightscaping you can purchase a handy little device that measures electrical load in watts and KW/H, even converting it into $ if you enter the right varialbles for your market. (They cost $50 or so) Then you can see for yourself just how much is saved using different types of dimmers.

Remember, that a 500watt transformer only uses the amount of power loaded onto it. (yes there is a 'power factor' to take into consideration) If you only have one 20w BAB loaded onto a 500watt transformer then that transformer will only be drawing slighting over 20w. If you reduce the load by choking it through a dimmer module (either primary or secondary side) then the electrical load will be reduced.

Have a great day.

MarcSmith
09-11-2007, 08:53 AM
not to take away from a sale, but has anyone thought of a compact fluorescent.... you might spend 3-400 in bulbs, but you'll get an instant savings on your bill...

NightScenes
09-11-2007, 09:26 AM
Ugh, talk about ugly lighting. This is fine indoors but there is now way that you use these things for landscape lighting.

NiteTymeIlluminations
09-11-2007, 10:16 AM
Not true!!! There are good fluor out there...funny alot of guy here put down buying landscape lightijng from home depot but think its the only place to buy other things like paddle fans and fluor bulbs...there are great fluor bulb out there if you buy them form a quailit distributor or mfr who knows fluor lighting...pay attention to kelvin...

NiteTymeIlluminations
09-11-2007, 10:17 AM
I specify alot of 3 watt and 5 watt fluor bulbs, 3000 kelvin, torpedo shaped.

David Gretzmier
09-11-2007, 10:19 AM
I'm not a big fan of compact flour's either. I use them inside. I think James and I are the only ones open to LED's out there at this time, but the ones with the best lumens and warm white color seem to be 12 volts. so you may have to convert to 12 volts and then switch bulbs to LED. An electrician will have to do the 120-12volt conversion.

there are some 120 volt LED mr-16's available, you might just have to look around. If the goal is to save electricity, then for around 20-50 bucks per fixture, warm white LED's may be the way to go on this. no electrician involved.

Try to look for the newer Cree q4 or q5 bin 3-LED arrays, or the new Luxeon Rebel 0100 bin 3-LED arrays coming online now. They offer the most lumens, warmest color, and give you close to what you can get from a 20 watt old style for about 3-6 watts.

Try to stay away from the old Luxeon III and V's, or "cree equivalent" as they really only mimic a 10 watt or so, even in arrays.

you can always just get one or three and do a test comparing the 120 volt existing to the new LED's and let the customer decide.

MarcSmith
09-11-2007, 11:18 AM
I agree that CFL's are not the prettiest, but if the guy just wants to save money on his electric bill and get an immediate savings, cfl is the way to go..

Switching form 120 to 12 then all new fixtures, it will take years to realize the energy saving since you'd have to offset the install cost first...

Pro-Scapes
09-11-2007, 12:10 PM
tim one other concern.

Is this a 1 story home ? 2 story with hard to reach fixtures ? From not only a learning stand point but to educate your client I would provide them with a proposal containing a variety of solutions. Unfortunatly there is probably not much profit in this job by installing new bulbs. I would guess with 50-60 sofit lights its a very good sized home. The client will need to decide if he wants to spend 10's of thousands to reinstall the system accordingly to make it 12v.

If its 2 story or more with hard to reach fixtures also consider the maint factor of this project.

I still stand by the ground mounted system with leaving the line voltage intact for when he needs the extra brightness. Pictures would definatly help in this case. Dont sacrafice the looks of the project to lower his power bill. I doubt he will be any happier

Lite4
09-11-2007, 08:31 PM
I have decided not to even mess with it. It just isn't worth the cost for the customer to switch them over. He is currently running 75watters in the cans now. Its a 2 story house, I will just have to talk him into some ground mounts for auxilliary lighting or he can reduce the wattage. I have not seen it at night yet, I am going up in a few hours to get a visual in the night.