What is the best method to add extra insulation to the window?

the first ting to do is caulk where glass wood meet. then caulk any gaps in the window trim. as far as i know...you cant over caulk. i like using the rope style calking its not messy and it handles like clay or play dough. if it gets dropped on the floor no bi deal pitch and start again. that will stop a good bit of cold air coming in.

when the gaps are taken care of wash the window and trim. then then fun stuff. bubble wrap on windows, and then shrink wrap...the kind you hit with a hair dryer. i read that a very leaky spot is the glides the thing that the window go up and down on.- covered those with bubble wrap too.

now lets talk drapes. all insulated drapes are not created equal. some have a foam backing...as it wears, the backing flakes off. the heaver the material the denser it should be. let it puddle on the floor. hot air rises, cold air sinks.

You should be able to buy insulating film at your local home center. It looks like a clear plastic film, and you press it against the window and then use a blow dryer to help seal it onto the window and the frame. It seals all the edges and keeps drafts out.

Have you considered installing window blinds? They give extra insulation winter and summer against cold and hot sun. I have them at every window in my house except where I had glass block installed.

Those honeycomb blinds are insulating.... http://www.brylanehome.com/decor/Honeycomb-Cellular-Pleated-Shade.aspx?PfId=402572&DeptId=15287&ProductTypeId=1&ppos=2&Splt=1&StyleNo=5996

id love to have honey.Comb blinds but my 50’s fixer is a bit quirky

Three M window insulation kits available at Home Improvement stores

Your window sounds like this one we have in a room that is not our living room (we call it the "blue room") I bought these cotton blue and white striped curtains at a yard sale. I hung blue flannel light weight sheets from the same hooks (or maybe I pinned them on to the regular drapery) anyway that works well . Now we use the window for plants so I just have a blue and white striped Roman shade that I found for free, we drop that down. Inexpensive fleece blankets make great insulators for regular curtains. I just use t pins to fasten them in.

How about hanging various throws, tapestry drapery material, or tablecloths between the windows and the drapes? It could be like a textile art gallery. 😇

take A candel or better yet an incense stick.....hold it near the window. That’s closed. Does it flutter? Does the smoke go one way or the other.

That’s one way to tell if cold air is getting in. If cold air come in hot air can get out. I like hot air.

Hi,

You could use Polythene sheet across windows or Clingfilm, or Polystyrene sheet, or you could have heavy winter drapes with blanket or thermal interlining. You could have Thermal Film applied to your windows. Best wishes.