Vacuum glazing units - Pilkington Spacia, Finero etc.

[brent stanley]

I've been helping a number of folks in North America get into reproduction sash work as well as manufacturing higher performance European windows and folks are always asking me about the "newish" vacuum glazing which provides U-Values, and internal surface temperatures similar to triple glazing with better solar heat gain but as little as 6 to 12mm total thickness. The margins of the units are sealed or "welded" with glass so there's no rubber gaskets to deteriorate over time. The overall benefits are thinner sash and frame using less materials for similar performance (frame U-Values go up) but drawbacks are (depending on manufacturer) limited sizes available and visible pillars and extraction valves.

I'm just wondering if anyone here has any experience with it? Seems like it might be an option for some situations.

B

[Kevin Jenness]

Sounds good on paper. If it were available in custom sizes it would be an attractive option. My guess is the equipment would be more expensive than that used for conventional igu's.

https://www.gw-news.eu/glass/vacuum-ig-unit-igu-thin-some-laminated-glass

and

https://www.pilkington.com/en/global/products/product-categories/thermal-insulation/pilkington-spacia

[Tom M King]

Are you familiar with the old Anderson glass that was double glazed, but all made in one piece? I redid a house with some of those in 2012, and not a single one had fogged up. I'm not sure when that house was built, but thinking probably early '70's.

One of the things I do is build exact reproduction sash, and fix old ones, but we use handblown cylinder glass. The houses are museums, typically unheated, so it was more important to do real historic preservation than remodel them into something modern.

[brent stanley]

Sorry, meant to include links. Here's another one:

https://www.fineoglass.eu/product/

As I understand it, the only ones available now are from Japan but I don't have prices yet. The French ones can go down to 8x8 panes where the pilkingon one's minimum is larger than that, so TDL might be limited. I believe there's a maximum too. Everything is pretty well custom ordered. The other advantage of course is weight savings. Some of the larger triples are asking a lot of some hardware and of course demand heavier sash components too.


Sounds good on paper. If it were available in custom sizes it would be an attractive option. My guess is the equipment would be more expensive than that used for conventional igu's.

https://www.gw-news.eu/glass/vacuum-ig-unit-igu-thin-some-laminated-glass

and

https://www.pilkington.com/en/global/products/product-categories/thermal-insulation/pilkington-spacia

[Kevin Jenness]

I have some large triple glazed igu's in my house which are far more effective than the double glazed units in the operable units. All of the seals will fail eventually. Thermally sealed units would be a great improvement as to thickness, weight and longevity. I will be interested to learn more about this. I remember the old Anderson windows - wonder why that technology faded?

[brent stanley]

I have some large triple glazed igu's in my house which are far more effective than the double glazed units in the operable units. All of the seals will fail eventually. Thermally sealed units would be a great improvement as to thickness, weight and longevity. I will be interested to learn more about this. I remember the old Anderson windows - wonder why that technology faded?

I get the impression that the technology needed to mature and it's just getting there now. I expect we'll see the size ranges increase over time too. The Pilkington ones have a fairly visible valve in one corner and some of the little pillars are visible too. The French/belgian ones seem to have a less visible valve and pillar assembly. I'm going to try to get my hands on some this winter. As I understand it, the Anderson ones had thermally sealed perimeters, but weren't vacuum "filled" which is key to the performance and thickness reduction. I have a client that does a lot of reproduction work in Victorian homes and is very interested in being able to offer some thermal performance while still looking very close to traditional windows.

[Tom M King]

The Anderson ones I was talking about were nothing but glass. The edges were rounded, and slightly irregular. There appeared to be nothing but glass in the structure, but there is a space between two "panes". I'm sure they were not the most efficient, because they weren't very thick. I only had a couple of the glass units out, and didn't study them closely.

[brent stanley]

The Anderson ones I was talking about were nothing but glass. The edges were rounded, and slightly irregular. There appeared to be nothing but glass in the structure, but there is a space between two "panes". I'm sure they were not the most efficient, because they weren't very thick. I only had a couple of the glass units out, and didn't study them closely.

I actually did some looking around and found one dissected. The margins were quite rounded. I also heard about some of them failing with too much differential pressure between inside and outside.

[Warren Lake]

I bought a morso chopper years back from a family that made doors and windows for at least 35 years. Family bus, day I went to pick the machine I spent hours hanging out and helping them clean the factory. Wife cried as they raised their kids there. Then they ordered Pizza and Beer.

They had a room where they made their own thermalpane windows. There is a door sitting beside me as i picked what sitting outside that I could stuff in the Wallywagon and think a second trip. Door is probably 2 1/4' or more thick. Pine Stave core with those interlocking joints forgot the name and then covered in pine either 1/4" or 3/8". Too lazy to get up to look close. The glass assembled was thick. The room was a clean room. This door has 15 panes in it. They did nice work and historic to match what was there but updated from how it was done way back.

[Richard Coers]

How does a thermo-pane window work when there is no thermal break between the two panes. Seems to me it would not be better than 2 panes of glass with no seal at all.

[Warren Lake]

maybe the wrong term, two pieces of glass with the spacer between. Not sure what the space was between the pieces of glass should have taken a sample any left over was going into the bin anyway. My parents had 50 year pine windows with the storm that goes on in the fall. Big air space with those. Got new windows at one point and my mother thought it was colder with the new ones. Maybe the big air space with the old windows was a good thing.

[brent stanley]

How does a thermo-pane window work when there is no thermal break between the two panes. Seems to me it would not be better than 2 panes of glass with no seal at all.

The panes are separated from each other like a double pane unit, except instead of having argon or xenon between them, the air is sucked out so there is a vacuum in the space. The lack of anything at all there makes a better thermal break than air or argon.

[Warren Lake]

that well may be what TWP did. I cant remember what I saw in that room equipment wise just it was sectioned off from the shop to keep it dust free.

[Joe Calhoon]

I remember reading about the vacuum technology a few years back. If I remember correctly a couple PHDs came up with the concept. Looks like it is developing and would be a dream come true if it works out. Fenesterbau in Germany was canceled when Covid started and postponed till summer this year. Hopefully it will happen and might see this technology there.
IG has come a ways now and is lasting longer but still leaves a lot to be desired. In North America there are a few good producers but where I live I have to go to either coast to get good units. I am double cursed having a shop at 8000 feet and some jobs as high as 10,000 foot elevation. Adding breather tubes to IG adds another risk of failure. A different vacuum technology is used in Europe to suck air out of the sealed units that are going to altitude to eliminate the tubes. In general the IG over there is better than what’s made here. Window makers there now expect the units to last 50 years. The triple units in my house have been in 20 years now and still OK. Way back the first double units I used failed after 10 years. A lot of IG failures can be attributed to improper installation.

For historical work Green Mountain glass has been my go to with their clean 1/4” sight lines. They were bought by a custom window company but think they still produce for other customers. Grids in the glass unit if they are done accurately work pretty well for historic work with SDL. Finding accuracy in this is another issue also. Another interesting technology in glass is Heat Mirror. They had a lot of failures starting out but think it is better now.

[Kevin Jenness]

For historical work Green Mountain glass has been my go to with their clean 1/4” sight lines. They were bought by a custom window company but think they still produce for other customers.

Green Mountain Glass does still do custom IGUs. I haven't ordered from them since the sale, but the owner stayed on for a while and the new owner has a reputation for high quality millwork, so I expect they are still making a good product.

I've never understood why their level of competence is so rare in the industry. The shop I used to work at has a graveyard of faulty IGUs from other manufacturers - wrong size, grids misplaced or the wrong color, trapped hairs, etc. If a millwork shop had their failure rate they wouldn't be in business long.

[Jim Becker]

I've seen some of those Euro style window systems in various videos on the 'Tube and they are intriguing, especially those that open multiple ways.

[brent stanley]

I've seen some of those Euro style window systems in various videos on the 'Tube and they are intriguing, especially those that open multiple ways.

They are very cool, with double and triple glazing an option now. Joe offers courses in how to make those styles of windows that are well regarded.

I have a tooling set coming for triple pane, casement style that offers Passivehaus-grade U-Values that I'm excited to try out. It's worth more than my truck but the windows it produces are very expensive traditionally too.

[brent stanley]

I remember reading about the vacuum technology a few years back. If I remember correctly a couple PHDs came up with the concept. Looks like it is developing and would be a dream come true if it works out. Fenesterbau in Germany was canceled when Covid started and postponed till summer this year. Hopefully it will happen and might see this technology there.
IG has come a ways now and is lasting longer but still leaves a lot to be desired. In North America there are a few good producers but where I live I have to go to either coast to get good units. I am double cursed having a shop at 8000 feet and some jobs as high as 10,000 foot elevation. Adding breather tubes to IG adds another risk of failure. A different vacuum technology is used in Europe to suck air out of the sealed units that are going to altitude to eliminate the tubes. In general the IG over there is better than what’s made here. Window makers there now expect the units to last 50 years. The triple units in my house have been in 20 years now and still OK. Way back the first double units I used failed after 10 years. A lot of IG failures can be attributed to improper installation.

For historical work Green Mountain glass has been my go to with their clean 1/4” sight lines. They were bought by a custom window company but think they still produce for other customers. Grids in the glass unit if they are done accurately work pretty well for historic work with SDL. Finding accuracy in this is another issue also. Another interesting technology in glass is Heat Mirror. They had a lot of failures starting out but think it is better now.

Thanks Joe, I was hoping you'd have some background there. I will look up the heat mirror product too, thanks for the info.

The little dots and the valve/nipple will always turn some customers off of the vacuum units, but for those that aren't bothered by it, they really could open up some doors for making windows that really look old school and period appropriate. I know so many people around me and where I grew up who are replacing perfectly functioning, but poor performing single pane, TDLs with vinyl atrocities just to get the performance upgrade. It's quite a blight on the face of historical buildings.

[Frederick Skelly]

I hadnt heard of the heat mirror product, but ran across this company site that describes it. Thought Id post it as just FYI for those not familiar, like me. LINK (https://longhomeproducts.com/blog/heat-mirror-windows-right-move-smart-homeowners/#:~:text=Heat%20Mirror%20windows%20are%20an,to%20a s%20%E2%80%9Cinsulating%20chambers.%E2%80%9D)

[Tom M King]

We have one heat mirror window, and it works great. The afternoon Sun can be shining directly on it, hold your hand against the inside glass, and can feel zero heat.

It's a big circle top window. The glass was sent to one of my neighbors as a replacement, but they sent the wrong size, and didn't want it back. I bought it for $15, and built the jamb for it. They had sent the inside curved stop along with the glass. The glass was 9' tall, and four feet wide.

I have one picture in the gallery here, but it only shows the top of that window. That was our weight room, but my almost 106 year old Mother is using it for a bedroom these days.

It works nicely.

[Joe Calhoon]

I've never understood why their level of competence is so rare in the industry. The shop I used to work at has a graveyard of faulty IGUs from other manufacturers - wrong size, grids misplaced or the wrong color, trapped hairs, etc. If a millwork shop had their failure rate they wouldn't be in business long.

Me neither Kevin. When I have to order Colorado made made IG through the local glass shops I always warn the customers it may not be without faults. I can send back anything I don’t like but after 2 or 3 times with the same thing I tend to give up. Ordering glass long distance can work if the quantities are large enough.
I have one of those graveyards myself! Some with my mistakes.:D

[Joe Calhoon]

Here is a picture of a Heat Mirror sample in a 92mm thick tilt turn sash. We were supposed to use this on a job several years ago but Alpen was going through a reorganization at the time and could not deliver. I think they are doing pretty well with it now.
473834

[Kevin Jenness]

I can send back anything I don’t like but after 2 or 3 times with the same thing I tend to give up.
��

Once we sent back a unit with a hair in it and got a "replacement" with the same hair. I guess they have the same policy.

[Warren Lake]

waiter what is that fly doing in my soup? " I think the back stroke"

Sad thing about service at times.

[Warren Lake]

Asked one of the past employees and he said they had a set up with a maxim size of their press, 4 x 4. Larger were ordered. Said they did use gas wasnt sure thought maybe Argon. I said that isnt that for Tig welding and he just could not remember. Had it set up that the gas went in and pushed the air out the other side.