Taking up curtains. Help!

I'd say it depends on which is more important to you, the look of the curtains (how nicely they hang) or the heat.

If the heat is more important I'd say shorten them so that they will just tuck behind the radiator when drawn, then all the heat will come into the room. If you want them to hang nicely, then I'd suggest windowsill length.

I had this dilemma. I don’t like short curtains and like you I thought the heart would just go behind the curtain anyway. In the end I bought blinds for the windows with thermal lining and left the curtains open. Sorry that’s probably not much help ?

Agree with Septimia, however my Mother used to teach home furnishings at College /night school.
She always said if you need to take curtains up do at the top not bottom. Unpick the heading of you want to use again or buy new. Correct the size from the top, sew on new heading tape, but you will need a sewing machine to make it easier.
The hem stays perfect.
Good luck

Just another thought... how about leaving the curtains full-length, but fitting a thermal blind inside the window recess and using that when the heating is on instead of closing the curtains?
You could close the curtains when the radiator is off so you'd still have that "look" then.

Polarbear2 crossed posts!

V3ra and Polarbear2 my thoughts exactly. I’m doing that in one room where the window sill length curtains are very fine and the heat from the radiator just goes up behind them. I usually keep them open as we aren’t overlooked.

Thank you for all your great suggestions and good advice. I'm going to investigate the thermal blind option which I hadn't thought about before. That's my homework for today.