Design Pleasantly Baffled (LED House Lights)

[JD]

Ok, there has been a push to convert all of our house lighting systems to LED and, as a conservationist, I have been on board. The side lights, sconces, all the PAR38s, no problem! So, then we came to the hanging lights over the congregation. 14 of them.

Each contained: Three, 75 watt R30 lamps facing up, Three 75 watt A-style lamps to light the body of the fixture, and one big old R52, 500 watt down-light. (total 950 watts each)

Since the up-lighting did nothing, I planed on changing those out to 2700k 11 watt LEDs. It was the down-light that worried me. As fat and inefficient as it was, it still was rated at about 7600 Lumens. I had good luck using the 17 watt PAR38 (2700k) LED lamps in other locations, but they are rated at 920 Lumens. So, for the heck of it, I placed three of them in the former "body light" position (which happened to face down) and put a mogul to medium adapter in the R52 position and put an 11 watt LED in that to light the body. According to my calculations, that would only give me 2760 Lumens of down-light. The PAR38's had a 40 degree spread. The R52 had no beam rating, but looked to be about 60 degrees. With one fixture equipped this way, and the other 13 still with the old lamps, it was time to kick things on and see HOW BAD the output would drop.... Remember, prior total wattage 950, new wattage 95.

So, the new unit is substantially brighter in every way! The down-light (28 feet elevation) is a total blow-away. I do not have a light meter, but it wasn't even in the same ballpark. The beam is somewhat tighter, but not enough in my mind to explain why the unit is so bright. Of course everyone was happy, so I should be happy. My problem is having an outcome that was so different then what I expected! I examined the old R52 to see if the loss was due to blackening or voltage, but they are 120 volts, and there was no real degradation to the reflective coating in the lamp. Just one of those things I guess.

 

[techieman33]

You can get light meter apps for newer smart phones. Don't get me wrong I'm not saying they'll be as good as a true light meter, but they'll get you in the ballpark, and will be more than sufficient for comparing to itself.

 

[David Ashton]

the other question is how does the colour compare, high colour temperature gives the illusion of brightness but tends to be a less pleasant fluoro look

 

[JD]

the other question is how does the colour compare, high colour temperature gives the illusion of brightness but tends to be a less pleasant fluoro look

I went with all 2700k lamps to match what people are used to, and indeed, they are darn close to the old bulbs. It's just crazy to stand and look at one of the old units, and one that's been converted side-by-side while lit, and comprehend that the brighter unit is using about 10% of the electric as the dimmer one!

I have to believe that much of the output of the older R52's must be either and over-rating, or is somehow lost off axis. At 28 feet, anything beyond 60 degrees probably would not hit the floor, and since the bottoms of the fixture contain concentric rings to block stray light, it may be lost there. These are the lamps that were spec'ed for the fixture back in 89'.

Still, my gut tells me that if I remove the baffle, it still won't compete. Depending on what time is available, I may try that on one fixture just to settle my mind.

One thing is for sure, if anybody is on the fence about LED conversion, I say go for it, or at least try it!

Those fixtures have been in used since 89' at about 20 hours a week. A little math tells me we have wasted 157 megawatt-hours just on the R52s!(450watts X 14fixtures x 20hours X 52weeks X 24years)
(Of course, it would have been a little hard to convert to a product that didn't exist yet!)

 

[MarfaLights]

Encouraging report. I'm making recommendations to replace our 100 Par38 house lights to LEDs...

 

[JD]

Encouraging report. I'm making recommendations to replace our 100 Par38 house lights to LEDs...

Highly recommend these:
Lighting Lampholders Ballast LED Fixtures CFL - TCP 17 Watt 2700K Dimmable PAR38 LED Lamp

Shop around. I was able to find a price of $38, and in that quantity, our local electrical supply house matched it and there was no shipping. They are a good match for replacing 95 to 120 watt PAR38s.

For an LED, they have a very smooth dimmer curve, and the 2700k is a real good color match.
Part # LED17E26P3827KFL sometimes listed as LED17E26P3827KF (same thing.)

 

[JD]

A quick update now that the project is done. (more info here- Green )
Changing out the 14 500 watt down-lights with sets of 3 17 watt LED pars still amazes me.
Total project replaced 30kw of standard lamps with 3k of LED.