Starting to feel the chill of winters approach

So my young grandkids are staying in a cold rental house, it's got the minuim legal requirements (underfloor and ceiling insulation and 1 heat pump in the living room). The house also has ill fitting single glaze aluminuim framed windows that the cold wind whistles through.

Being a rental, absolutely no holes allowed in anything and not allowed to mark the bad interior paint work, so how can I do some sort of double glazing???

Perhaps twinwall polycarb, with an interferance fit into the frame might be the answer?

A test at my house (with heater on) had a 10 degree difference between the glass and the plastic - 9 degree C for the glass, 19 for the plastic. 

So today I go to the supplier dressed in jeans and strippy jumper to get a couple of large sheets before visiting the mall.

Around lunch time, it was getting a bit warm, so I swapped my jumper for a cardigan and decided to visit a cute cafe for Devonshire tea.

On the way home I had to pick up wifes medication and get a couple of items from the supermarket (milk, makeup remover wipe etc).

Eventually I had to change into boy mode, and install the twinwall polycarb (because my car is very cramped with the sheets in it so I'm not waiting until next weekend). Just got to wait a day or two to find out how it's changed the rooms temperature.

UPDATE - getting lots of thanks from family only hours after installing the twinwall, toes not frozen and granddad is a great engineer 😀