Energy efficiency of these bulbs?

[JohnW2]

I must admit lazy both opening and drawing curtains ....

You don't need to be lazy about both - if you don't do one, you don't need to do the other

Kind Regards, John

 

[ericmark]

I have considered automating curtains, mainly as summer sun when we get some, can over heat the room, so it is too hot when we come to use it, not to save walking to curtains, but when we are not there.

The curtains are on a pull cord, but wonder if it should be some external blind?

Also K glass™ may be an option. I think it acts as a one way valve, but which way, can it be reversed summer and winter, so in winter it lets the heat in and not out, and in summer lets heat out and not in?

I don't really understand how it works but remember some problems when installed wrong way around. There is also add on films which I know work, as seen it used on a batching plant cabin where the sun was making it very hot, often referred to as one way film, as it can stop one seeing what people behind the glass are doing, definitely needs to be right way around in a bathroom, if some one thinks it is a mirror they could give a good display.

But the problem in the UK is Summer and Winter what we want reverses, so maybe triple glazing, however it seems Everest who were best know for triple glazing have been caught out with some dirty tricks, including going into administration so they do not honour warranties.

I idea of replacing the third glass in summer for a fly screen seems good, but where do you put the glass? The French seemed to have a good idea with the shutters, but never been in a French home with them closed, it must be very dark?

 

[Harry Bloomfield]

I idea of replacing the third glass in summer for a fly screen seems good, but where do you put the glass? The French seemed to have a good idea with the shutters, but never been in a French home with them closed, it must be very dark?

When I was working in Italy, the hotel I stayed in, had wooden lath roller shutters at the window on the outside, operated by a strap through the wall to the inside. the laths had gaps between them, so you could close it so it just touched down, with the gaps letting some light it, or all the way down and no light getting in. They were quite common fitment in the area.

In the UK, I have seen shades fitted to modern buildings, in the form of slats fitted to brackets above windows. When the sun shines near straight down, it gets to shine on the ground, but the slats limited the sun from shining in through the windows.

 

[RandomGrinch]

In the UK, I have seen shades fitted to modern buildings, in the form of slats fitted to brackets above windows. When the sun shines near straight down, it gets to shine on the ground, but the slats limited the sun from shining in thr

"Brise soleil" - they work absolutely brilliantly, it made a huge difference installed on the south facing, four storey lab block where I work.
I would love a couple on my rear windows, but the problem for me is they are only available commercially - DIY options don't seem to be available in the UK.
I am going to settle for a cheap roll down awning for now - hopefully options will improve in the future.

 

[JohnW2]

Also K glass™ may be an option. I think it acts as a one way valve, but which way, can it be reversed summer and winter, so in winter it lets the heat in and not out, and in summer lets heat out and not in?

I don't know what "K glass" is, but I'll try to find out when I have some moments. However, as I and others have told you, any sort of glass (at least, any sort I know of) will exhibit the 'greenhouse effect' - i.e. it will let in enough UVA that sunlight will be able to warm the inside of a building, but will prevent heat (IR) escape by radiation through the window (but some heat may go through by conduction, if it's cold outside).

I suppose one could put a UV-reflective coating on the glass to prevent the inside being heated by sunlight, but I don't think you could do anything about the fact that IR can't get out of the room through glass - so I find it hard to see how it could be particularly 'reversible'.

If I discover more, I'll let you know!

Kind Regards, John

 

[RandomGrinch]

I don't know what "K glass" is

I presume he means 'Pilkington K' glass?:

Pilkington K Glass™ | Trusted Low‑E Thermal Insulation Glass

Pilkington K Glass™ is the original hard‑coated, low‑emissivity glass trusted across the UK for over 20 years. Designed for energy-efficient IGUs, it reflects heat back into the room while allowing solar gain | helping achieve top Window Energy Ratings and reduce heating bills

www.pilkington.com

 

[JohnW2]

I presume he means 'Pilkington K' glass?:

Pilkington K Glass™ | Trusted Low‑E Thermal Insulation Glass

Pilkington K Glass™ is the original hard‑coated, low‑emissivity glass trusted across the UK for over 20 years. Designed for energy-efficient IGUs, it reflects heat back into the room while allowing solar gain | helping achieve top Window Energy Ratings and reduce heating bills

www.pilkington.com

Thanks. The description seems to suggest that it reduces even further the transparency of glass to IR but, since I thought that was pretty low in the first place (with 'ordinary' glass) I wonder how much benefit it actually provides?

... or is there perhaps more to it than that?

Kind Regards, John