My house is insulated pretty well. Cavity insulation and rigid board insulation throughout. A real weak spot is the kitchen bifold doors. Not much room for blinds/curtains. I wondered if anyone had any ideas to help reduce heat loss?

Tape many fluffy kittens to them to keep in the heat

Last week we rented a very old flat and it has sash windows. In addition to curtains, it had fold out wood panels that were recessed into the side wall. These could fold out and cover the whole window. They actually very effective for both heat loss and noise. Since it's really the winter months that heat loss is a problem. Maybe you could have a temporary thing that clips on etc. that could give additional insulation and remove them in the summer so you can open the doors if needed? You might also have old seals that are drafty and could just be replaced.

[Edited on 4/11/22 by Mr Whippy]

Some years back living in a rented flat with bay / sash windows they had the same as Mr Whippy describes. Living on a busy road they certainly helped reduce the noise. They had been built into the window frames when the place was built (the whole bulding had them).

Forget the company name, but there's advertes on TV at the moment for thermal roller blinds. No doubt they cost a bit and it would take a while to recoup the money, but it might be a way to go if you have limited installation space.

Probably the most costly solution would be to replace the actual glazing units with triple glazed units. Pricey though! One of those how long are you going to be there questions for you.

[Edited on 4/11/22 by nick205]

Do any of them work very well? They strike me as the kind of thing destined to fail and then be leaky mal-adjusted frustrations forever more.

The U-value of 28mm double glazing is around 1.2, so you're effectively replacing a cavity wall that has a U-value of 0.3 with something that won't also leak/bypass.

Genuine question by the way, as I've pondered putting some in myself.

Screw fix sell silver foil insulation that could be fitted to the windows with tape
to help heat loss
Graham

there are clip in thermal blinds that are available - they are made from multiple layer fabrics and can have a thermal lining - try blinds to go or similar. Once easy to clip in or out and they add additional insulation and remain smart looking

HTH