Area Light Mounting Height

[Bull]

I want to mount an area light on the front of my barn. The goal would be to light the area in front of the doors, but I'd love it if the light also lit up my driveway, which is between the barn and my house. I am unsure as to whether I should mount the light lower, or higher. Lower, and I worry that the light won't be able to spread out far enough. But higher, I worry that the three in front of the barn will soak up all the light (when it has leaves) before it can reach the ground.

The picture needs to be zoomed, but hopefully you can see the red lines where I identify the two possible mounting locations, based on where inside the structure I have wiring that I can tap into. What do you think?

Here is the light/kind of light I am looking at.
http://www.amazon.com/dp/B000HM7QXA/?tag=atomicindus08-20

 

[FJ 432]

If you went with a halide light I think the higher option would be fine.

A typical barn light would look better in the lower position (the type that has a single bulb with an upper shade).

Is your photo taken from your house? If so do you have an option of having a light switch placed in your house so that you could turn the light off and on? It would be nice to set a powerful light on a switch so that you could turn it on for guests and turn it off so you can sleep at night!

 

[stratman977]

That fluorescent light will be somewhat weak for what you want to do. You will want high pressure sodium or mercury vapor. I have a 70 watt high pressure sodium light installed at 12' and it would definitely light up the area in front of the garage nicely and it gives off light up to 100'. AT 100' you can see where you're walking but if you dropped a quarter you wouldn't find it. The make a 150 watt version of the hps light also which would work nicely for your high up mounting position. The arm that gets them away from the side of the building also seems to make a difference.

I could not find a usa built version of those outdoor lights but I would recommend buying a qualty fixture cause the cheap ones last about a year and then you have to climb up the ladder again and replace the ballast.


By the way 65 watt fluorescent is 4,000 lumens, 150 watt hps is 15,800 lumens.

http://www.amazon.com/dp/B002NU56FO/?tag=atomicindus08-20

 

[MoonRise]

Just how much light are you looking for?

Just enough that it is lit somewhat?

Or enough that you could do some work in the driveway (change a tire, check the tire pressure, etc), but not brain surgery?

Do you want light-spill to the edges, or is a bright spot in the middle what you want?

Are you trying to avoid having the light(s) shining into/onto the house, or do you want the light to pretty much reach all (or most of) the way to the house? (assumption that your picture was taken near the house and facing the barn/garage.)

The flood light down-light fixture that you posted would probably work OK to light up the area directly underneath it, but won't 'reach' all that far. The light fixture is directing the light downward, and fluorescent lights usually are more of a flood light than a spot light (optics not withstanding).

I would probably put two light switches in, one for the low-position flood light and the second with a double or triple light fixture up at the high position. Put the flood light on dusk-to-dawn sensor mode, and then turn on the higher output spot lights at the high-position as needed with their separate switch.

As mentioned, that 65W fluorescent is about 4000 lumens (when new, with the tube and electronic ballast warmed up and operating at full output, cause fluorescents usually have a reduced output when first fired up especially when cold).

4000 lumens, rated output might give you a more real-world output of about 80% (fixture lighting efficiency, light-spill going the 'wrong' way, etc) of that, so 3200 lumens.

Spread that 3200 lumens across an estimated area of 22-24 ft wide by about the same distance away from the barn, so an area of approximately 484-576 ft^2, gives a light level of about 5.5 to 6.6 lumens/ft^2. Which is a relatively dim light level IMHO. Adequate to maybe not trip, but you're not going to be doing much work with that sort of light level. Cut the light level in maybe half for when it is raining or snowing and things will be a bit dim. Maybe you could find that dropped quarter, or maybe not.

YMMV.

 

[skyking]

Just put a cheap Mercury vapor at the highest point . You will be happy with that and it is an easy install .

 

[skyking]

Btw....cool upstairs area. Not too fond of double garage doors though.

 

[ishiboo]

I would put an energy efficient light at the highest-most position, such as a metal halide or mercury vapor.

I would then install one or two 500W halogen task lights at the mid-point. These are only about $10-15 a piece. They provide a warm halogen light good for working on tasks in the driveway and instant on.

I have this setup and most of the time I use the 500's as task lights and leave the mercury off, but for energy efficiency reasons if I was going to leave one on it'd of course be the mercury.

 

[stratman977]

I dont know if this will help but i'm standing about 60' from the light in the picture. The shed to the right is about 65' away. I think you would have plenty of light if you mount at the middle point. I prefer the yellow light from the high pressure sodium, it just seems less harsh than the white light. I don't have any problems with light glaring into the house at around 60' to 70' from window to the light.

 

[Norcal]

Mercury vapor is pretty much obsolete, the ballasts have gone the same way as a lot of T12 ballasts, no longer able to be imported or manufactured in the USA. The only advantage mercs have over other sources is looooong life, there is more bang for the buck with other HID sources such as metal halide, or high pressure sodium. At this time HID is the best choice over LED since they are still too new & too expensive ATM.