Insulating single glazed windows

[Cofty]

Hi. Anyone know how best to insulate a single glazed window? I don't mean the frame, more the air travelling through the single glass layer.
Obviously secondary glazing is an option, but too expensive. The windows in question are not used / opened, so perhaps some kind of film, or thick plastic cover with magnet strips to add a second layer?
Any help or best practice advice would be great.
Cofty

 

[^woody^]

more the air travelling through the single glass layer.

That's not glass, its mesh!

Any sort of secondary glazing will still tend to allow condensation to form on the external glass

Film is crap. Acrylic or polycarbonate sheet or better still glass in a secondary frame would be a better option

 

[ajrobb]

Condensation can be a problem if you don't seal the cavity from the room and don't ventilate it to outside. I have just used uPVC edging as a spacer and fitted second panes of glass (360x520 mm) held in place with silicone sealant and some uPVC quadrant. I drilled 3x6mm holes through the bottom of the frame for external ventilation and plugged them with glass wool to discourage insects. These line up with 3x3mm holes drilled through the bottom spacer. I was pleased to see the slight condensation in the second window begin to clear in the first hour.

This is intended to be a 'permanent' solution to condensation after replacing the rest of the windows with uPVC DG (with frame vents). These last windows are too small for thick uPVC double glazing frames. To call them windows is a bit of an overstatement; they are small holes in the wall lined with 2x2 and glazed.

The living room was painted with emulsion 2 days ago. The house is currently empty but heated to 18°C and the trickle vents are open. After the cold snap last night, I was disappointed to see condensation on these windows this morning, so decided to 'fix' them. We used a similar technique to double glaze wooden French windows years ago and never had a condensation problem.

My parents-in-law had secondary acrylic glazing fitted to draughty sash windows. There was plenty of ventilation to the outside and a reasonable seal from the room. They had no problem with condensation last winter.