The missus has got big plans for the breatheeasy manor extension which seems to involve replacing the entire rear wall with glass sliding doors.

To add to the moon on a stick requirements when I suggested that everyone and their cat would be able to see into the rear of the house and curtains/blinds would be a bit impractical shes invented some sort of science fiction system whereby the windows can be darkened/frosted at a flick of a switch.

Googling this seems to suggest this might even actually be possible with electrochromic (smart) glass.

Anyone had any experience? Just want to stop the expensive juggernaut in its tracks before it gains too much momentum if it’s not feasible.

Systems like that are available, seen ’em on that Kevin McCloud show…I have no idea about price, but I’m going to hazard a guess that its not often specified at the budget end of the market.

I’ve seen a couple of installations through my work as a district surveyor, & whilst they can have the “wow factor” when you flick the switch, I should think that would soon wear off but, more importantly I thought the glazing, when switched off, was optically very poor & was vaguely opaque. Also v expensive.

I’ve visited a couple of offices that had it in internal windows (to close off meeting rooms etc)
bit of a gimic but it worked quite well.

Why not go for units that contain the Venetian blind in the air gap between the glass panes which are opened/closed with a magnet

IIRC smart glass runs from a few hundred/m2 to over a 1K/m2. As above double glazed units with blinds integrated may(?) be a bit cheaper and more practical for your situation

I thought the glazing, when switched off, was optically very poor & was vaguely opaque.

This, the one time I’ve seen it I thought it was like looking through safety glasses or a motorbike helmet, it’s like glass, but not quite.

That and I guess it doesn’t have the insulating proerties of curtains so might be colder?

I’ve only ever seen it used on internal walls though (like the meeting room example) so I guess it’s there to let natural light in rather than provide a view.

Why not go for units that contain the Venetian blind in the air gap between the glass panes which are opened/closed with a magnet

Or put the shading outside where it’ll work properly. With that amount of glass you’re surely going to see a huge increase in fuel bills, no?

With that amount of glass you’re surely going to see a huge increase in fuel bills, no?

+1 Our conservatory is not a good place to be on a frosty night.

We stayed at a holiday home a while back that had them in one room. As above the glass had an odd look to it as if it was lined with plastic. Not actually that noticeable but something like that tends to attract close scrutiny like the machining on a Hope brake for example

The tinted effect was not particularly even either. Effective but not even.

IIRC smart glass runs from a few hundred/m2 to over a 1K/m2.

Maybe smart casual glass is a bit cheaper?

igmc.

Priva-lite

As above glass is slightly milky and its very expensive. Not really used in domestic situations, normally for meeting rooms etc. What direction does the rear of the house face as if its south you will definately want some decent blinds or preferably a brise soleil to stop you cooking in the summer.
If you want your house to look like an office you could have internal venetian blinds in the glass. Shouldn’t have much of a problem being cold in winter as the building control spec for glazing is so much higher than a few years ago.

sounds expensive- the wife as well as the windows 😯

or preferably a brise soleil to stop you cooking in the summer.

Does this Brise Soliel prevent heat loss in the winter?

With that amount of glass you’re surely going to see a huge increase in fuel bills

Depends very much on the windows. High end triple glazed (often no extra charge on European windows as pretty much standard there now) folding sliding doors can get to a u value of about 1. A solid brick wall is around 2 for comparison – in an old uninsulated house it might improve things.

Which way will it face?

IIRC – its natural state is opaque and when the elastictrickery is turned ‘on’ thats when it goes clear…….so constant electric usage when its in the clear state

You could have electronic blinds?

A solid brick wall is around 2 for comparison – in an old uninsulated house it might improve things.

If that’s the case I’d be looking to reduce this figure before spending on flashy windows. 😀

Privalite is circa £1k/m2. Also with a fold sliding door, not entirely sure how the wiring would work.

If you want something cheaper (but still expensive) check out interstitial blinds. They sit inside the double glazed unit, look fancy and are nearly as good a way spend money as ‘smart’ glass.

Brise soleil is solar shading, so won’t keep any heat in during the winter.

Slack man the clue to that is in the name. Well done. What will keep the heat in is enough insulation to meet building regs in the extension and glass of required u value. It’s not like this kind of extension is anything unusual. Although saying that building orientation is important. You wouldn’t put loads of glass on a northern elevation.

We could do something but damn we’d be expensive with that! 5m folding door sets are fairly normal for us, but with that glass you are looking at the £1k/m2 plus the joinery plus the electrical connections plus the installation. Roughly, I’d be surprised if its less than 20k for a reasonable size. Cheaper to get a new wife?

Cheaper to get a new wife?

or shutters?

What will keep the heat in is enough insulation to meet building regs in the extension and glass of required u value.

I could stand corrected on this, but isn’t the maximum permitted u-value for windows something ridiculous like 1.8W/m²k in order to satisfy building regs? That’s poor.

Just want to stop the expensive juggernaut in its tracks before it gains too much momentum if it’s not feasible.

I think the moment you said ‘I do’ was when that engine started 😀

Give us a bit more detail on this plan then.

We have bifold doors the full width of our kitchen, which overlooks open country. Having nothing at night feels uncomfortable because it’s a big area of blackness and you can’t help feeling exposed. I wouldn’t want the self-darkening liquid crystal glass because it’s black and probably damned expensive and would take a long time to get a unit replaced whereas with plain DG units any glazier can make them up and fit them. We have radio-controlled Somfy blinds, which roll down and give us a relective white surface at night and keep the sun out in summer (it faces west so the solar gain is huge).

The Somfy blinds are battery-powered and the batteries last about 2 years with twice or thrice daily use, we have now replaced the battery wands (which are just a stack of 8 AA batteries in a cardboard tube giving 12 volts) with refillable wands, where you can buy AAs from Maplin and refill them yourself. You can get mains-powered blinds but the programming of the individual blinds is apparently much more difficult thanks to the common supply.

Yes, you can also get the DG units with blinds inside but interior Somfy roller blinds are much cheaper.

You cant make it out brilliantly from the photo but this south facing barn opening is fitted with double glazing with blinds integrated in the void between the panes. They are each controlled (tilt and lift) by a magnetically actuated wheel in the top.

They have been excellent in use. By tilting the blinds upwards we can minimise sunlight in summer, but allowing some privacy, and then in winter tilt them down to maximise solar gain on the stone floor from what sunlight we can capture.

However, a number of the units have “Blown”. The manufacturer has come out and agreed that the problem is in fabrication and has replaced one of the units as an experiment. If it’s still fine by spring he will remake the others too.

The difference in price for each panel (there are eight on this side with blinds in) was £50 versus £290. Its quite a bit more, but it means never having to clean the blinds and also blinds/drapes not acting as radiators being hit by sunlight in summer. By intercepting the sunlight inside the glazing unit it minimises the conversion of that light to heat on the inside of the glass. The eight panels on the opposite north facing opening dont have blinds fitted as they arent needed.

Cheers globalti and Stoner, thats useful information.

I suspected the problems with the fancy window idea would be price and getting them to work on bifold doors.

Give us a bit more detail on this plan then.

And I blame Sarah Beaney on this one – single floor rear extension – basically the kitchen, dining room and utility room all sit side by side at the back of the house. We’re thinking of pushing out the back the full 4m, taking out the old rear walls for those three rooms (but leaving the side walls if that makes sense) so that they all basically merge into this one big area. And bifold doors across the whole of the back feeding into the garden. And pitched roof of course…

So there’s gonna be a massive expanse of glass at the back we’d just like to put a bit of privacy on. Internal blinds seem to be the saner solution at the moment.

Cheaper to get a new wife?

Ha, ha, I should have know a lot earlier after seeing the engagement/wedding rings she picked… 😯

The difference in price for each panel (there are eight on this side with blinds in) was £50 versus £290.

Would it be rude to ask how much these blinds work out to per m²?

dj,
£270 for 850mm x 1307mm
£290 for 850mm x 1804mm

Both those sizes were £48 for no-blind versions.

M

Wow! That’s seriously expensive. 😯
Thanks.

if you were trying to extrapolate on a sqm basis then yes. The incremental cost is only £20 for an extra 0.4m2 so I imagine its £200 a unit + something for glass and scale.

I also imagine they’re starting from a minimum order size of maybe 1,5m² and knocking a bit off to look good. 😉
Be interesting to see the price list though.

and how much are you shutters per unit then dj? 😉

Insulated alu shutter with concealed box and guides and manual operation will come out at £150 per m² and a motor would set you back another, let’s say, £150, to be on the safe side, obviously this depends on shutter size. Same functions and more for less money. Not sure where you’d get hold of them at that price mind. 😉
EDIT: I imagine that price would include delivery to site too.

Four Somfy radio-controlled blinds, floor to ceiling and each 840mm wide, cost about £400 including a measuring visit then professional installation and programming.

dj – so £170ish for each of those panels.
Compared to £270 average for integrated blinds.

Do your shutters louvre for a combination of light & privacy?
Do they need cleaning?
Are they not goppingly ugly externally hung things?

didnt think so, I can live with the extra £100 😉 😛

Do your shutters louvre for a combination of light & privacy?
Do they need cleaning?
Are they not goppingly ugly externally hung things?

Lolz.
I think the perforations will give you the light and privacy that you’re looking for.
Of course they will need cleaning, but if this is important we can sacrifice some of the performance and install them internally.
If you’re worried about gopping ugly externally hung things, we could discuss in detail the hidden boxes and hidden guides. If you still think they’re gopping, I’ll have to learn to live with the fact that we don’t all like the same things. 😀
Gopping is making the decision very personal and while there are people who think they’re gopping, there are people who think that the fact that these internal blinds make the home look like an office makes them equally gopping. There are some who believe that not only are these shutters beneficial in performance levels, but also add to the aesthetic of the building. A question of taste, innit?
The fact we have different tastes is what makes my job so enjoyable. 😉