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