There are all kinds of gadgets for animals. We were tempted to try the Radiator Bed for cat on radiator.
Here is the report:
Tested in a house with 2 cats, it was quickly adopted (10 min after installation) by one of the cats. It is used by the cat only in heating season and very regularly.

Constraints :gripette
Not suitable for all models of radiators because if too deep the hammock becomes bent; Thin models such as French 2 or 3 columns do well.
Also, the radiator should not be too high for the cat to climb.

The original fabric ends up stretching and the hammock becomes deep but the cat continues to go anyway. Modifying the attachment to the frame would be fine.

Finding: it is still a good product and is well liked by some cats!
7/10 bought on ebay