Why don't more houses use glass in their roofs?

[desura]

After seeing the Elon Musk Solar City presentation, it occurred to me that simply making a large portion of the roof out of glass could save substantially for home heating costs. And because it is on the roof, there aren't privacy concerns. I guess during summer it could get too hot, but there could be like a retractable shade or something, no? Or just crank up the AC.

 

[ControlD]

Most houses have an attic / insulation between the roof and the living area. A glass roof wouldn't be a privacy concern, but it would probably significantly heat up the void space between the roof and the attic floor.

 

[desura]

Most houses have an attic / insulation between the roof and the living area. A glass roof wouldn't be a privacy concern, but it would probably significantly heat up the void space between the roof and the attic floor.

Eh, I'm thinking you could get rid of the attic area so you have an expanded space and lots of natural light.

 

[OutHouse]

After seeing the Elon Musk Solar City presentation, it occurred to me that simply making a large portion of the roof out of glass could save substantially for home heating costs. And because it is on the roof, there aren't privacy concerns. I guess during summer it could get too hot, but there could be like a retractable shade or something, no? Or just crank up the AC.

my home heating cost are cheap thanks to natural gas. Cooling is where i spend the big bucks.

also a glass roof and a hail storm would not end well.

 

[edro]

Because plywood and asphalt shingles are cheap and rugged.

 

[deadlyapp]

You would need two or three layer glass, likely thicker than usual to handle loading, and you'd need a very UV opaque coating to prevent heat loading. It's simply not practical.

Plus, not everyone likes the idea of being able to see all the super structure that you would need to hold up all the weight of that glass.

 

[nakedfrog]

I feel like nearly every thread you post is dumb, but not quite dumb enough to make you a troll.

After seeing the Elon Musk Solar City presentation, it occurred to me that simply making a large portion of the roof out of glass could save substantially for home heating costs. And because it is on the roof, there aren't privacy concerns. I guess during summer it could get too hot, but there could be like a retractable shade or something, no? Or just crank up the AC.

Yeah, at least until there are commonly available, cheap airborne remote control vehicles with cameras in them.

 

[Red Squirrel]

It would be super energy inefficient. Normally you have about 2-3 feet worth of insulation in the attic which is to be treated as outside space. You want it well ventilated and the same temperature as outside to prevent ice damming from snow melting from under. You can build sky lights that go all the way down to the living space but it's generally a thermal loss more than it is a gain even from the sun light. When the sun is even out. (most of winter, it's not as the days are short) Not to mention the glass would be covered in snow most of the year and when it does melt you have ice damming to worry about, ex: there are more seals and seems involved than just shingles.

There are some interesting sky light ideas though that involve a tube, and work kinda like a periscope. If these stick out high enough through the roof and end up not covered in snow, and are well insulated they can add some natural light inside the house without that much of a thermal loss. Generally though it's best to minimize the amount of penetrations going in the ceiling and roof. For the ceiling, it means more potential air loss in the vapour barrier as it's an extra thing that needs to be sealed, and the roof it's a potential leak point.

Some people have cathedral ceilings where sky lights would work better instead of an attic you just have an insulated rafter space, similar to a wall, but that leaves less room for insulation, and often can have problems if not done right.

Now what would be really efficient is a south facing wall that has large windows and a big overhang and a dark room. In winter the sun would go right through and shine in the room, in summer the sun is a bit higher up and the overhang would shade most of the windows. This would take some rather good engineering and planing to get right though. Curtains help, but once sun has reached curtains it's still inside the thermal envelope of the house.

 

[OutHouse]

id rather not live in a greenhouse.

 

[iroast]

* Glass is heavy and expensive compared to traditional roofs. The cost is in the glass itself, the foundation to support the glass, the weather proofing involved, etc.
* Glass adds heat.

Assuming that you're retrofitting, you would have to pay for tearing down the old roof and reinforcing roof structure. You would also need to install cooling vents (solar powered?), or motorize the opening/closing of panels. Once you have your new roof up, you would need to renovate the attic to make it into a usable space. What you gain:

Pros:

* Great looks
* Added value to your house
* Sunbathing in privacy
* Relaxing on a rainy day
* Star gazing
* Greenhouse

Cons:

* Professional glass cleaners needed?
* Cost

 

[desura]

It would be super energy inefficient. Normally you have about 2-3 feet worth of insulation in the attic which is to be treated as outside space. You want it well ventilated and the same temperature as outside to prevent ice damming from snow melting from under. You can build sky lights that go all the way down to the living space but it's generally a thermal loss more than it is a gain even from the sun light. When the sun is even out. (most of winter, it's not as the days are short) Not to mention the glass would be covered in snow most of the year and when it does melt you have ice damming to worry about, ex: there are more seals and seems involved than just shingles.

There are some interesting sky light ideas though that involve a tube, and work kinda like a periscope. If these stick out high enough through the roof and end up not covered in snow, and are well insulated they can add some natural light inside the house without that much of a thermal loss. Generally though it's best to minimize the amount of penetrations going in the ceiling and roof. For the ceiling, it means more potential air loss in the vapour barrier as it's an extra thing that needs to be sealed, and the roof it's a potential leak point.

Some people have cathedral ceilings where sky lights would work better instead of an attic you just have an insulated rafter space, similar to a wall, but that leaves less room for insulation, and often can have problems if not done right.

Now what would be really efficient is a south facing wall that has large windows and a big overhang and a dark room. In winter the sun would go right through and shine in the room, in summer the sun is a bit higher up and the overhang would shade most of the windows. This would take some rather good engineering and planing to get right though. Curtains help, but once sun has reached curtains it's still inside the thermal envelope of the house.

I like this lots.

 

[JoeBleed]

You would need two or three layer glass, likely thicker than usual to handle loading, and you'd need a very UV opaque coating to prevent heat loading. It's simply not practical.

Plus, not everyone likes the idea of being able to see all the super structure that you would need to hold up all the weight of that glass.

Not to mention the combined weight of the glass itself would be a lot heaver than standard roofing materials. This is about as bad as the whole "solar freaking roadways" and such. On, and Elong's "hyper loop"....

 

[zinfamous]

Yeah, at least until there are commonly available, cheap airborne remote control vehicles with cameras in them.

I was thinking the same thing until I told myself that this will never happen.

 

[Humpy]

After seeing the Elon Musk Solar City presentation, it occurred to me that simply making a large portion of the roof out of glass could save substantially for home heating costs. And because it is on the roof, there aren't privacy concerns. I guess during summer it could get too hot, but there could be like a retractable shade or something, no? Or just crank up the AC.

Why haven't you installed a glass roof on your house?

 

[zinfamous]

It would be super energy inefficient. Normally you have about 2-3 feet worth of insulation in the attic which is to be treated as outside space. You want it well ventilated and the same temperature as outside to prevent ice damming from snow melting from under. You can build sky lights that go all the way down to the living space but it's generally a thermal loss more than it is a gain even from the sun light. When the sun is even out. (most of winter, it's not as the days are short) Not to mention the glass would be covered in snow most of the year and when it does melt you have ice damming to worry about, ex: there are more seals and seems involved than just shingles.

There are some interesting sky light ideas though that involve a tube, and work kinda like a periscope. If these stick out high enough through the roof and end up not covered in snow, and are well insulated they can add some natural light inside the house without that much of a thermal loss. Generally though it's best to minimize the amount of penetrations going in the ceiling and roof. For the ceiling, it means more potential air loss in the vapour barrier as it's an extra thing that needs to be sealed, and the roof it's a potential leak point.

Some people have cathedral ceilings where sky lights would work better instead of an attic you just have an insulated rafter space, similar to a wall, but that leaves less room for insulation, and often can have problems if not done right.

Now what would be really efficient is a south facing wall that has large windows and a big overhang and a dark room. In winter the sun would go right through and shine in the room, in summer the sun is a bit higher up and the overhang would shade most of the windows. This would take some rather good engineering and planing to get right though. Curtains help, but once sun has reached curtains it's still inside the thermal envelope of the house.

one thing you and the OP need to realize: the entire world does not have the same climate that you guys (or at least, you) are familiar with. The OP seems to think this is a fix-all solution, where it is probably only a decent idea in only certain parts of the world. You seem to think it is the best idea ever because you are only familiar with one climate--your own.

you guys should get married and start making glass-roof houses the polar regions of the planet where no one else wants to live.

 

[nakedfrog]

I hereby volunteer my services as officiant for the pending nuptials, and wish both grooms all the happiness in the world!

 

[ponyo]

Great idea. Let's spend $50,000 to save $20 a month on heating cost.

 

[GagHalfrunt]

Yeah, at least until there are commonly available, cheap airborne remote control vehicles with cameras in them.

That's never going to happen, so stop droning on about it.

 

[zerocool84]

Great idea. Let's spend $50,000 to save $20 a month on heating cost.

Yea seriously, gas is no where near as expensive as electricity.

 

[Rubycon]

Because too many people throw stones.

 

[John Connor]

Because hail would play hell and the eventual leakage over time. I would not have one damn skylight in my house. Talk about running up the AC bill too!

 

[John Connor]

Couldn't even fuck in piece.

 

[Red Squirrel]

Yea seriously, gas is no where near as expensive as electricity.

It's actually crossed my mind to cancel hydro service and just get a natural gas generator. There's probably bylaws about constant excessive noise though and generators tend to be loud. It's too bad because electricity is more green, but they keep jacking up the prices to ridiculous levels. It's the delivery that's a killer. It's like more than half the bill, which also means there's not much incentive to reduce usage as it won't make a big difference.

Then they're turning around and going to have a carbon tax soon, just to add insult to injury.

Wood stove + steam turbine would be nice, but they'll probably ban wood stoves soon I'm sure. They don't want people to be self sufficient.

 

[Rubycon]

It's actually crossed my mind to cancel hydro service and just get a natural gas generator. There's probably bylaws about constant excessive noise though and generators tend to be loud. It's too bad because electricity is more green, but they keep jacking up the prices to ridiculous levels. It's the delivery that's a killer. It's like more than half the bill, which also means there's not much incentive to reduce usage as it won't make a big difference.

Then they're turning around and going to have a carbon tax soon, just to add insult to injury.

Wood stove + steam turbine would be nice, but they'll probably ban wood stoves soon I'm sure. They don't want people to be self sufficient.

Cost to generate your own power is going to be hideously expensive like over fifty cents a kWh.

That's why so many get suckered into believing stuff like this!

https://www.youtube.com/watch?v=Fv53K9MnDuM&feature=player_embedded

 

[zinfamous]

Couldn't even fuck in piece.

How many pieces does it normally take?