When you figure it out send it to my neighbor plz.

So are you trying to limit the amount of light transferred from the inside of the home to the outside? What is the purpose of trying to do so if this is your intent? Privacy?

Let me see if I understand your question: "...The new house I am building will have a lot of glass. It will light up at night. I am looking for ways to limit it while it is comfortably bright inside..."

So...you're not wanting any interior light to reach the exterior...is that right?

Have you considered window coverings?

Landscaping/trees, window tint, window treatments, automated blinds, exterior lights on timers/dimmers... Depends who/what is around you

So are you trying to limit the amount of light transferred from the inside of the home to the outside?

Yes. To keep it dark for the neighbors. Without window coverings.

Also consider what rooms of your neighbors are looking at your home. If it's garage/bathroom/etc then screw it. But if it's a bedroom you want to be courteous. aka no flood lights lol

Have your neighbors voiced any concerns? Are they worried what they may observe viewing into the all glass bathroom?

Short of everyone in the house wearing night vision glasses, I would think if all your light fixtures and lamps projected light down and nothing was there to reflect the light horizontally, that would keep light generated from within your home outward to offend your neighbors.

Inviting your neighbors over in the late evening often would also reduce the opportunities for them to complain.

You may be over thinking this.

Why are you opposed to window covering? There are tons of options that are out there that are minimal and barely noticeable when installed.

Are you a tall house?

I think there is no really good answer. Window coverings, design - ie low with roof overhangs, and landscaping/fencing. I would also suspect that low Vt windows would help some.

But I have to say I was expecting a discussion on outdoor lighting....

Are you concerned at all about being on display? Not that you're planning on running naked races through the house (although maybe you are!) but a house lit from within with no window coverings when it's dark outside puts the residents on display. Reading, TV watching, dining.... neighbors will see in easily if they are close by.

Install a tint film on windows to

limit light, a fairly inexpensive solution.

It is to keep the night sky dark. No one can see through my house from a distance. The bathroom is sheltered from view unless they are in my property.

Are you a tall house?

@David, Kind of. It is a low house at a high spot. What is low Vt window?

But I have to say I was expecting a discussion on outdoor lighting....

There is an old discussion on the outdoor lighting. It suggests using shades, pointing down, and to avoid blue light. I will employ all that except pointing down. I like warm lights and do not like glare of a bare bulb anyway.

Have your neighbors voiced any concerns? Are they worried what they may observe viewing into the all glass bathroom?

@Mark, They could be concerned. No. No one can see into the bathroom unless they are on my property.

Why are you opposed to window covering?

It has to be more permanent than a window covering that I may choose not to pull down.

"They could be concerned."

Have an open conversation with your neighbors before proceeding about your (honorable) concerns. I moved into a home that had a side door light that projected light in every direction. Because of my concern that it disturbed the neighbors I changed the fixture to one that projects all the light down. I asked the neighbor if he noticed any difference and he said, "It never bothered me".

Well...choose interior and exterior light fixtures and placements where the light source is not visible, and only the actual work areas are illuminated. No chandlier, no pendants, no table lamps, no neon signs. None of those.

Recessed cans and surface mounted cans are two types of fixtures which will work.

Is this a regulatory requirement?

Low Vt - visible transmission. It is a measure of how much light comes through a window. A .5 Vt means that 50% of the light is blocked. Now - I think that means visible wavelengths and it is a measure of how much sunilght comes in. I would guess (although not sure) that it would be a good measure of what comes out.

No chandlier, no pendants, no table lamps, no neon signs. None of those.

If you do for some reason end up with a chandelier, pendants, or table lamps, do make sure they have lamp shades. No bare bulbs (or clear glass in the case of the pendants) of any kind. Lamp shades go a long way toward minimizing glare and "escaping" light.

No chandlier, no pendants, no table lamps,....

Sounds like a death sentence! Wouldn't they be ok if all the bulbs are shaded or diffused?

Is this a regulatory requirement?

Kind of although they don't seem to know how strict they want to be. But I agree to keep dark sky dark and would like do my part regardless of regulation.

If you do for some reason end up with a chandelier, pendants, or table lamps, do make sure they have lamp shades. No bare bulbs (or clear glass in the case of the pendants) of any kind.

I can do that happily. I don't like glare anyway or clear glass, much prefer frosted.

The only way illumination will not radiate through lamps shades, pendant globes and chandeliers is if the shades, globes and other materials surrounding the lamps are completely light proof, i.e., metal with no perferations. Normal cloth and glass shades, globes and the like allow substanial light to penetrate and illuminate the surroundings.

Either you want to limit ambient light or you don't.

Virgil, they illuminate the surroundings but are much more contained, even with normal cloth shades. One can of course also get shades in darker colors, though that limits the amount of light the homeowner can enjoy.

There comes a point where you have to decide whether you're going to live life in your new house for yourself or your neighbors. Get window coverings -- automated/mechanized/motorized if it makes it easier for you to deal with them every evening -- and be done with it : ) .

At night the windows will be big black holes. Unless, of course, you illuminate the out-of-doors.

I saw a modern treatment one time (you need to plan for it before hand because it's heavy) of stainless steel chainmail that can be drawn across the plate glass windows. It doesn't eliminate light transfer but reduces it. And it looks great inside.

Yep, Becky, that's the point here. The great majority of light fixtures are purposely designed to create ambient light which provides general interior illumination for a space. In so doing the light on the interior is visible from the exterior, and, in turn, washes out into the exterior to a greater or lesser degree.

What the OP is attempting is virtually impossible without window coverings, especially for "a lot of glass". The situation is a bit of an oxymoron.

I think there's a window tinting that you can apply where you can adjust the tint with your smart phone. You could have it clear during the day and tinted at night.

Probably ridiculously expensive though.

I saw a modern treatment one time (you need to plan for it before hand because it's heavy) of stainless steel chainmail that can be drawn across the plate glass windows.

Could you elaborate it?

Just google "chainmail curtains" and you'll see a bunch of examples.

Will do!

What the OP is attempting is virtually impossible without window coverings, especially for "a lot of glass". The situation is a bit of an oxymoron.

Not necessarily. Some light or light configurations must dissipate sooner than others. That's what I need to find.

Fighting light pollution generally doesn't come from your glass, it comes from well designed homes in well designed areas with attention paid to lighting height and cover.

http://ruralplanning.org/assets/dark-sky---web.pdf

Here is an example of a dark sky house.

ETA: I don't know that the above example is the best, but basically you try to eliminate surfaces that are horizontal and reflective. Try to get lights above windows so the entire house acts as an opaque shade that directs light down. Lights below the tops of windows should be downlighting, etc.

Is a dark sky design what the OP is seeking? I got the impression the OP was concerned about light spilling out of her/his house and illuminating the neighbor's property.

"...are you trying to limit the amount of light transferred from the inside of the home to the outside? Yes. To keep it dark for the neighbors. Without window coverings..."

That doesn't sound like a dark sky objective to me. But I could be wrong...

Here is where the definitions get a bit specific. Light pollution is defined as the brightening of the night sky by man made sources. Now he might not have intended it that way, so I could be taking it wrong.

However, he mentioned dark sky and light pollution, so my assumption is that he wants to counteract his light polluting his neighbor's sky rather than being worried about some reasonable distance around his house. I could be incorrect, but the information is there if anyone does a future search for this topic.

I have a close friend who is an astronomy nut and he raves about our farm because of our effort to protect dark sky. Which we accomplished completely by accident, and our farm house has a similar amount of glass as the one above.

Yes, I meant neighbors' sky. Could you elaborate what else you did?

Well...whatever the OP's intent...the very simple and easiest strategy is to conceal the light sources from direct view. No pendants, no wall mounted fixtures, no chandeliers, no fixtures of any kind where one may see the direct light source from inside or outside the house.

Said differently, all of the direct light sources are shielded from view in one way or another.

Even with this stategy, the indirect light and bounce light are still a challenge.

It's much easier to reduce the illumination impact as seen from 20,000 feet than it is to keep one's interior illumination, even indirect illumination, from being seen from the neightbor's property at ground level.

Large window areas transmit light. There's simply no getting around that, unless or until something stops the interior light from reaching the exterior.

So on the farm we have to be able to see into the fields at night with a spotlight to count the horses, yes horse thieving is still a thing...

This means that we need to protect night vision and so all of our lights project a circle on the ground that you can walk out of. We just use the classic barn gooseneck lights. Outside at night, you are never more than a few steps from darkness. We keep the lighting warm for the exact same reason. I think dark sky is recommended below 3000 kelvin.

If a picture is worth a thousand words, here is what you are going for outside.

-------

Inside we have a lot of task lighting rather than lighting up entire spaces. This works better anyway. Our lighting over the sofa illuminates our knees and the table sofa table and doesn't directly hit our faces when we are reclining on the sofa. We can see the remote well, eat in that room and are still comfortable watching television.

We have several shielded pendants that work well but no open pendants. We also have quite a bit of recessed lighting that is really close to walls that provide interior light but are largely shielded by those walls.

I suspect the most difficult part is controlling light trespass and secondary light sources. Basically I would think you don't put a light in an area because of some pattern of light positions and instead focus on what you want lit and what you don't want lit and design your lighting plan that way.

I do suggest you find someone with real experience to get advice from rather than someone who accidentally achieved what you are going for.

I am sure what you did is as good as any expert can come up with. I may need a little more light than that. The house in your picture seems quite well lit. I'd be happy with it. It has pendants. I can't tell what they did that made them a dark sky house. I am planning to get a lighting designer. But I have a feeling this is not an exact science and they may not be much help unless they are experienced in that area.

OP, are you building near a Dark Sky Park or other designated area where this is a requirement? Or might you contact one and ask for THEIR advice on how to minimize the scatter from everyday lighting on your project?

Something like that. I think they are still making up their codes and it is not quite designated yet. Their advise would be limit the glaze. I meet their requirement. It's really not an issue but I'd like to keep the dark sky dark beyond minimum to meet the code. I think it's wonderful to have so many stars in the sky.

I think it's wonderful to have so many stars in the sky.

Here is a picture edited only to approximate human vision in a real dark sky environment (not mine). The picture doesn't really do it justice but you can get the idea.

ETA: I am pretty happy that dark sky awareness is starting to catch on.

Many communities across the U.S. have been addressing this for years with zoning ordinances which require outdoor steet, parking and other lights to be shielded down lights which do not throw any light upward.

I was also going to ask about the Dark Sky designation and where the OP is from. Seeing the Milky Way and all the stars is absolutely amazing. Seems most people don't get to live or visit a place where you can see it so clearly. Stunning to say the least.

Though I am not sure there is much to do inside a home to keep the light from venturing outwards that isn't going to be either A) visible or B) super expensive to do if you want it nearly invisible.

Photo credit: Babak Tafreshi

To be fair, human eyes can't detect color in the milky way so the second photo is a bit misleading.

Maybe to the extent of that photo due to it being a long exposure I'm sure, but I have seen it very close to that with the naked eye.