My wife tells me it has charm - charm is the opposite of insulation.
This weekend I have been attending to the glazing. My house has painted uPVC single leaded glazing. It must have been special order as I've never seen it anywhere else; we inherited it with the house. It has none of the good bits of uPVC, no sound deadening, no heat insulation and it needs regular maintenance thanks to the paint, nice.
To keep the house habitable, every year I trot to B and Q and buy 35 sq m of ultra-thin polyethylene terephthalate sheet. This is stuck onto the window frames on the inside with double sided tape and shrunk till taught using a hair dryer. The result is unbelievable.
Without this secondary glazing, the house is freezing. I know if you do all the heat losse calculations, this does not look like it could be true, but trust me single glazing leaves a steady cold draft pouring off every window in the house, meaning only the middle of the room is warm. On paper, the payback of double glazing might be centuries, but who can measure the payback for comfort?
Here is a simple bit of payback maths for this technology - cost of sheeting £35, cost of fitting £0... I did it myself. Cost of not doing it, 1 x unhappy wife. You do the maths.
As far as the Green Deal is concerned I could not be bothered to apply, at £35 a year this is the best money I have ever spent.
Once I get my RHI for my heat pump I might even buy some proper double or triple glazing... bring on the money.