How to make single glazed windows more energy efficient?

[fadetoblack]

Hi All, 
I recently bought an old town house with predominantly west facing single-glazed windows and am now looking at adding an extra glaze to the windows to make it more energy efficient. 

Due to budget constraints, I'm looking at a DIY project using either acrylic and/or polycarbonate materials for the second glaze. 

I'm just writing to see if anyone has any recommendations on using the two materials?
Can both materials be pre-treated – maybe with a tint?– to block UV and mitigate direct sun?
Also, for the sake of better security, is it possible to install the polycarbonate panels on the outside (first floor anyway) effectively? 

Any tips on the subject would greatly appreciated. 

Thanks in advance, 

[fadetoblack]

Thanks so much Richard.
May I ask why you used the corrugated polycarbonate instead of the flat version which is closer to a window pane? 

[EricL]

Hello @fadetoblack 

Thank you for posting those extra pictures. It looks like @RichardC used Suntuf Sunlite 8mm x 610mm x 3.0m Clear Twinwall Polycarbonate Roofing and at certain angles it does look like corrugated polycarbonate. But let's wait for Richard's confirmation on what product they used. 

In regards to your own project, using the twin wall would be a much better option as it is light weight, easy to cut and install when compared to Perspex. If you are not bothered with the reduction of visibility, installing the twin wall on either the inside or outside should not be an issue.

My best advice is to make sure that the twin wall polycarbonate does not get in the way of the operation of the window. I strongly advise testing it first just to be sure.

If you have any other questions we can help with, please let us know.

Eric

[RichardC]

Hi fadetoblack & Eric,

You're right Eric, I used the Sunfuf clear twin wall polycarbonate, not corrugated.

As we know, trapped air is a pretty good insulator so by sealing off the cut ends I trapped air in each tube so that is what makes it work.

Regards,

Richard

[EricL]

Hi @RichardC 

Thanks for confirming that, I'll tag @fadetoblack to make sure they see your response.

Eric

[RichardC]

Eric, you're a Bunnings employee.

Hard work & dedication are one thing, but you shouldn't be replying to work emails, ie working at 10pm!

Regards,

Richard

[EricL]

Hi @RichardC 

It's all part of the service, I'm happy to help.

Eric

[fadetoblack]

Thanks for this, I really appreciate it. 
clear visibility is important for us, so I think we'll just use the clear, single walled I guess, sheets.

[RichardC]

Hi fadetoblack,

Very sensible. The stuff works, but you'd be silly to put it where visibility is important. A single clear sheet on the outside, preferably trapping a layer of air would have to help moderate the temperature of the glass.

It is a lot more work & expense, but if your windows are timber framed, it should also be possible to remove the glass, increase the depth of the rebate & then fit custom made double glazed units. The internal gap between the panes of glass will probably be less than optimal, but it works. The double glazed unit does of course add a fair bit of extra weight. That wasn't a big issue when I did it to a couple of french doors, but I did have to upgrade the springs when I did it to a double hung window. Doing this improved thermal performance, whilst enabling me to preserve the fabric & appearance of my heritage building.

Good luck!

Richard

[fadetoblack]

Thanks Richards, 
This is beginning to sound a bit more complex than I thought, I may look to get a professional in.
I initially saw this video, this video, and this thought I might be able to do it on the outside for security reasons. 
I'm now starting think high quality smash-resistant and solar reduction film might be the way to go instead. 

Once again, thanks so much for all your tips!

[RichardC]

Hi fadetoblack,

Yes, no easy/obvious solutions I'm afraid!

Obviously you need to be careful not to solve one problem whilst unwittingly creating another, eg a heat reflecting film may be good in the middle of Summer, but may make your place colder in the Winter!

If the main issue you're wishing to address is unwanted heat gain in the Summer, perhaps some way of keeping the sun off the glass, like retractable awnings on the outside could be an option worth exploring? 

Improving ventilation can also do a lot to help cool a house. As we know, hot air rises, so perhaps you could add an opening skylight to let that air out whilst drawing in cooler/fresh air from the cooler/shady side of the house?

Good luck!

Richard