Draughty Cat Flap!

[MagicKingdom17]

No, it’s not a euphemism .
We recently had a cat flap installed into our utility door for our cats. It obviously lets in a draught and makes the whole kitchen chilly.
Does anyone have any tips to cut down on the draught?

Put a shower cap over it, my cat has learnt to remove it when she wants to go out. It makes a hell of difference .

My cat would be so traumatised by a shower cap that she’d never use the cat flap again.
We stuck draught-proofing all round the flap bit. It needs replacing often but helps.

Curtain in front of door? The cat just goes behind the curtain to go out.