Installing Underfloor Heating in an exisiting concrete floor

[BillBags]

Currently have a solid floor in my kitchen and I am extending the kitchen out by 2 meters. Hence I have no issues with installing underfloor heating in the new area but would also like to install it in the current part of the kitchen that has a solid floor.

What involved in doing this? i.e. how much of the concrete floor needs to be dug out?

Pro and cons?

or am I mad going down this route :-)